Struct clap::Arg

pub struct Arg { /* private fields */ }

The abstract representation of a command line argument. Used to set all the options and relationships that define a valid argument for the program.

There are two methods for constructing Args, using the builder pattern and setting options manually, or using a usage string which is far less verbose but has fewer options. You can also use a combination of the two methods to achieve the best of both worlds.

• Basic API
• Value Handling
• Help
• Advanced Argument Relations
• Reflection

Examples

// Using the traditional builder pattern and setting each option manually
let cfg = Arg::new("config")
      .short('c')
      .long("config")
      .action(ArgAction::Set)
      .value_name("FILE")
      .help("Provides a config file to myprog");
// Using a usage string (setting a similar argument to the one above)
let input = arg!(-i --input <FILE> "Provides an input file to the program");

Implementations

impl Arg

Basic API

pub fn new(id: impl Into<Id>) -> Self

Create a new Arg with a unique name.

The name is used to check whether or not the argument was used at runtime, get values, set relationships with other args, etc..

NOTE: In the case of arguments that take values (i.e. Arg::action(ArgAction::Set)) and positional arguments (i.e. those without a preceding - or --) the name will also be displayed when the user prints the usage/help information of the program.

Examples

Arg::new("config")

Examples found in repository

src/builder/command.rs (line 4240)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn id(self, id: impl Into<Id>) -> Self

Set the identifier used for referencing this argument in the clap API.

See Arg::new for more details.

Examples found in repository

src/builder/arg.rs (line 108)

    pub fn new(id: impl Into<Id>) -> Self {
        Arg::default().id(id)
    }

pub fn short(self, s: impl IntoResettable<char>) -> Self

Sets the short version of the argument without the preceding -.

By default V and h are used by the auto-generated version and help arguments, respectively. You will need to disable the auto-generated flags (disable_help_flag, disable_version_flag) and define your own.

Examples

When calling short, use a single valid UTF-8 character which will allow using the argument via a single hyphen (-) such as -c:

let m = Command::new("prog")
    .arg(Arg::new("config")
        .short('c')
        .action(ArgAction::Set))
    .get_matches_from(vec![
        "prog", "-c", "file.toml"
    ]);

assert_eq!(m.get_one::<String>("config").map(String::as_str), Some("file.toml"));

To use -h for your own flag and still have help:

let m = Command::new("prog")
    .disable_help_flag(true)
    .arg(Arg::new("host")
        .short('h')
        .long("host"))
    .arg(Arg::new("help")
        .long("help")
        .global(true)
        .action(ArgAction::Help))
    .get_matches_from(vec![
        "prog", "-h", "wikipedia.org"
    ]);

assert_eq!(m.get_one::<String>("host").map(String::as_str), Some("wikipedia.org"));

Examples found in repository

src/builder/command.rs (line 4241)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn long(self, l: impl IntoResettable<Str>) -> Self

Sets the long version of the argument without the preceding --.

By default version and help are used by the auto-generated version and help arguments, respectively. You may use the word version or help for the long form of your own arguments, in which case clap simply will not assign those to the auto-generated version or help arguments.

NOTE: Any leading - characters will be stripped

Examples

To set long use a word containing valid UTF-8. If you supply a double leading -- such as --config they will be stripped. Hyphens in the middle of the word, however, will not be stripped (i.e. config-file is allowed).

Setting long allows using the argument via a double hyphen (--) such as --config

let m = Command::new("prog")
    .arg(Arg::new("cfg")
        .long("config")
        .action(ArgAction::Set))
    .get_matches_from(vec![
        "prog", "--config", "file.toml"
    ]);

assert_eq!(m.get_one::<String>("cfg").map(String::as_str), Some("file.toml"));

Examples found in repository

src/builder/command.rs (line 4242)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn alias(self, name: impl IntoResettable<Str>) -> Self

Add an alias, which functions as a hidden long flag.

This is more efficient, and easier than creating multiple hidden arguments as one only needs to check for the existence of this command, and not all variants.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
            .long("test")
            .alias("alias")
            .action(ArgAction::Set))
       .get_matches_from(vec![
            "prog", "--alias", "cool"
        ]);
assert_eq!(m.get_one::<String>("test").unwrap(), "cool");

pub fn short_alias(self, name: impl IntoResettable<char>) -> Self

Add an alias, which functions as a hidden short flag.

This is more efficient, and easier than creating multiple hidden arguments as one only needs to check for the existence of this command, and not all variants.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
            .short('t')
            .short_alias('e')
            .action(ArgAction::Set))
       .get_matches_from(vec![
            "prog", "-e", "cool"
        ]);
assert_eq!(m.get_one::<String>("test").unwrap(), "cool");

pub fn aliases(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self

Add aliases, which function as hidden long flags.

This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                    .long("test")
                    .aliases(["do-stuff", "do-tests", "tests"])
                    .action(ArgAction::SetTrue)
                    .help("the file to add")
                    .required(false))
            .get_matches_from(vec![
                "prog", "--do-tests"
            ]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);

pub fn short_aliases(self, names: impl IntoIterator<Item = char>) -> Self

Add aliases, which functions as a hidden short flag.

This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                    .short('t')
                    .short_aliases(['e', 's'])
                    .action(ArgAction::SetTrue)
                    .help("the file to add")
                    .required(false))
            .get_matches_from(vec![
                "prog", "-s"
            ]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);

pub fn visible_alias(self, name: impl IntoResettable<Str>) -> Self

Add an alias, which functions as a visible long flag.

Like Arg::alias, except that they are visible inside the help message.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                .visible_alias("something-awesome")
                .long("test")
                .action(ArgAction::Set))
       .get_matches_from(vec![
            "prog", "--something-awesome", "coffee"
        ]);
assert_eq!(m.get_one::<String>("test").unwrap(), "coffee");

pub fn visible_short_alias(self, name: impl IntoResettable<char>) -> Self

Add an alias, which functions as a visible short flag.

Like Arg::short_alias, except that they are visible inside the help message.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                .long("test")
                .visible_short_alias('t')
                .action(ArgAction::Set))
       .get_matches_from(vec![
            "prog", "-t", "coffee"
        ]);
assert_eq!(m.get_one::<String>("test").unwrap(), "coffee");

pub fn visible_aliases(
    self,
    names: impl IntoIterator<Item = impl Into<Str>>
) -> Self

Add aliases, which function as visible long flags.

Like Arg::aliases, except that they are visible inside the help message.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                .long("test")
                .action(ArgAction::SetTrue)
                .visible_aliases(["something", "awesome", "cool"]))
       .get_matches_from(vec![
            "prog", "--awesome"
        ]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);

pub fn visible_short_aliases(self, names: impl IntoIterator<Item = char>) -> Self

Add aliases, which function as visible short flags.

Like Arg::short_aliases, except that they are visible inside the help message.

Examples

let m = Command::new("prog")
            .arg(Arg::new("test")
                .long("test")
                .action(ArgAction::SetTrue)
                .visible_short_aliases(['t', 'e']))
       .get_matches_from(vec![
            "prog", "-t"
        ]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);

pub fn index(self, idx: impl IntoResettable<usize>) -> Self

Specifies the index of a positional argument starting at 1.

NOTE: The index refers to position according to other positional argument. It does not define position in the argument list as a whole.

NOTE: You can optionally leave off the index method, and the index will be assigned in order of evaluation. Utilizing the index method allows for setting indexes out of order

NOTE: This is only meant to be used for positional arguments and shouldn’t to be used with Arg::short or Arg::long.

NOTE: When utilized with [Arg::num_args(1..)], only the last positional argument may be defined as having a variable number of arguments (i.e. with the highest index)

Panics

Command will panic! if indexes are skipped (such as defining index(1) and index(3) but not index(2), or a positional argument is defined as multiple and is not the highest index

Examples

Arg::new("config")
    .index(1)

let m = Command::new("prog")
    .arg(Arg::new("mode")
        .index(1))
    .arg(Arg::new("debug")
        .long("debug")
        .action(ArgAction::SetTrue))
    .get_matches_from(vec![
        "prog", "--debug", "fast"
    ]);

assert!(m.contains_id("mode"));
assert_eq!(m.get_one::<String>("mode").unwrap(), "fast"); // notice index(1) means "first positional"
                                                          // *not* first argument

pub fn trailing_var_arg(self, yes: bool) -> Self

This is a “VarArg” and everything that follows should be captured by it, as if the user had used a --.

NOTE: To start the trailing “VarArg” on unknown flags (and not just a positional value), set allow_hyphen_values. Either way, users still have the option to explicitly escape ambiguous arguments with --.

NOTE: Arg::value_delimiter still applies if set.

NOTE: Setting this requires Arg::num_args(..).

Examples

let m = Command::new("myprog")
    .arg(arg!(<cmd> ... "commands to run").trailing_var_arg(true))
    .get_matches_from(vec!["myprog", "arg1", "-r", "val1"]);

let trail: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
assert_eq!(trail, ["arg1", "-r", "val1"]);

pub fn last(self, yes: bool) -> Self

This arg is the last, or final, positional argument (i.e. has the highest index) and is only able to be accessed via the -- syntax (i.e. $ prog args -- last_arg).

Even, if no other arguments are left to parse, if the user omits the -- syntax they will receive an UnknownArgument error. Setting an argument to .last(true) also allows one to access this arg early using the -- syntax. Accessing an arg early, even with the -- syntax is otherwise not possible.

NOTE: This will change the usage string to look like $ prog [OPTIONS] [-- <ARG>] if ARG is marked as .last(true).

NOTE: This setting will imply crate::Command::dont_collapse_args_in_usage because failing to set this can make the usage string very confusing.

NOTE: This setting only applies to positional arguments, and has no effect on OPTIONS

NOTE: Setting this requires taking values

CAUTION: Using this setting and having child subcommands is not recommended with the exception of also using crate::Command::args_conflicts_with_subcommands (or crate::Command::subcommand_negates_reqs if the argument marked Last is also marked Arg::required)

Examples

Arg::new("args")
    .action(ArgAction::Set)
    .last(true)

Setting last ensures the arg has the highest index of all positional args and requires that the -- syntax be used to access it early.

let res = Command::new("prog")
    .arg(Arg::new("first"))
    .arg(Arg::new("second"))
    .arg(Arg::new("third")
        .action(ArgAction::Set)
        .last(true))
    .try_get_matches_from(vec![
        "prog", "one", "--", "three"
    ]);

assert!(res.is_ok());
let m = res.unwrap();
assert_eq!(m.get_one::<String>("third").unwrap(), "three");
assert_eq!(m.get_one::<String>("second"), None);

Even if the positional argument marked Last is the only argument left to parse, failing to use the -- syntax results in an error.

let res = Command::new("prog")
    .arg(Arg::new("first"))
    .arg(Arg::new("second"))
    .arg(Arg::new("third")
        .action(ArgAction::Set)
        .last(true))
    .try_get_matches_from(vec![
        "prog", "one", "two", "three"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);

Examples found in repository

src/builder/arg.rs (line 1587)

    pub fn raw(mut self, yes: bool) -> Self {
        if yes {
            self.num_vals.get_or_insert_with(|| (1..).into());
        }
        self.allow_hyphen_values(yes).last(yes)
    }

pub fn required(self, yes: bool) -> Self

Specifies that the argument must be present.

Required by default means it is required, when no other conflicting rules or overrides have been evaluated. Conflicting rules take precedence over being required.

Pro tip: Flags (i.e. not positional, or arguments that take values) shouldn’t be required by default. This is because if a flag were to be required, it should simply be implied. No additional information is required from user. Flags by their very nature are simply boolean on/off switches. The only time a user should be required to use a flag is if the operation is destructive in nature, and the user is essentially proving to you, “Yes, I know what I’m doing.”

Examples

Arg::new("config")
    .required(true)

Setting required requires that the argument be used at runtime.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required(true)
        .action(ArgAction::Set)
        .long("config"))
    .try_get_matches_from(vec![
        "prog", "--config", "file.conf",
    ]);

assert!(res.is_ok());

Setting required and then not supplying that argument at runtime is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required(true)
        .action(ArgAction::Set)
        .long("config"))
    .try_get_matches_from(vec![
        "prog"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn requires(self, arg_id: impl IntoResettable<Id>) -> Self

Sets an argument that is required when this one is present

i.e. when using this argument, the following argument must be present.

NOTE: Conflicting rules and override rules take precedence over being required

Examples

Arg::new("config")
    .requires("input")

Setting Arg::requires(name) requires that the argument be used at runtime if the defining argument is used. If the defining argument isn’t used, the other argument isn’t required

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires("input")
        .long("config"))
    .arg(Arg::new("input"))
    .try_get_matches_from(vec![
        "prog"
    ]);

assert!(res.is_ok()); // We didn't use cfg, so input wasn't required

Setting Arg::requires(name) and not supplying that argument is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires("input")
        .long("config"))
    .arg(Arg::new("input"))
    .try_get_matches_from(vec![
        "prog", "--config", "file.conf"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn exclusive(self, yes: bool) -> Self

This argument must be passed alone; it conflicts with all other arguments.

Examples

Arg::new("config")
    .exclusive(true)

Setting an exclusive argument and having any other arguments present at runtime is an error.

let res = Command::new("prog")
    .arg(Arg::new("exclusive")
        .action(ArgAction::Set)
        .exclusive(true)
        .long("exclusive"))
    .arg(Arg::new("debug")
        .long("debug"))
    .arg(Arg::new("input"))
    .try_get_matches_from(vec![
        "prog", "--exclusive", "file.conf", "file.txt"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);

pub fn global(self, yes: bool) -> Self

Specifies that an argument can be matched to all child Subcommands.

NOTE: Global arguments only propagate down, not up (to parent commands), however their values once a user uses them will be propagated back up to parents. In effect, this means one should define all global arguments at the top level, however it doesn’t matter where the user uses the global argument.

Examples

Assume an application with two subcommands, and you’d like to define a --verbose flag that can be called on any of the subcommands and parent, but you don’t want to clutter the source with three duplicate Arg definitions.

let m = Command::new("prog")
    .arg(Arg::new("verb")
        .long("verbose")
        .short('v')
        .action(ArgAction::SetTrue)
        .global(true))
    .subcommand(Command::new("test"))
    .subcommand(Command::new("do-stuff"))
    .get_matches_from(vec![
        "prog", "do-stuff", "--verbose"
    ]);

assert_eq!(m.subcommand_name(), Some("do-stuff"));
let sub_m = m.subcommand_matches("do-stuff").unwrap();
assert_eq!(*sub_m.get_one::<bool>("verb").expect("defaulted by clap"), true);

impl Arg

Value Handling

pub fn action(self, action: impl IntoResettable<ArgAction>) -> Self

Specify how to react to an argument when parsing it.

ArgAction controls things like

• Overwriting previous values with new ones
• Appending new values to all previous ones
• Counting how many times a flag occurs

The default action is ArgAction::Set

Examples

let cmd = Command::new("mycmd")
    .arg(
        Arg::new("flag")
            .long("flag")
            .action(clap::ArgAction::Append)
    );

let matches = cmd.try_get_matches_from(["mycmd", "--flag", "value"]).unwrap();
assert!(matches.contains_id("flag"));
assert_eq!(
    matches.get_many::<String>("flag").unwrap_or_default().map(|v| v.as_str()).collect::<Vec<_>>(),
    vec!["value"]
);

Examples found in repository

src/builder/command.rs (line 4243)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn value_parser(self, parser: impl IntoResettable<ValueParser>) -> Self

Specify the typed behavior of the argument.

This allows parsing and validating a value before storing it into ArgMatches as the given type.

Possible value parsers include:

• value_parser!(T) for auto-selecting a value parser for a given type
  • Or range expressions like 0..=1 as a shorthand for RangedI64ValueParser
• Fn(&str) -> Result<T, E>
• [&str] and PossibleValuesParser for static enumerated values
• BoolishValueParser, and FalseyValueParser for alternative bool implementations
• NonEmptyStringValueParser for basic validation for strings
• or any other TypedValueParser implementation

The default value is ValueParser::string.

let mut cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("color")
            .long("color")
            .value_parser(["always", "auto", "never"])
            .default_value("auto")
    )
    .arg(
        clap::Arg::new("hostname")
            .long("hostname")
            .value_parser(clap::builder::NonEmptyStringValueParser::new())
            .action(ArgAction::Set)
            .required(true)
    )
    .arg(
        clap::Arg::new("port")
            .long("port")
            .value_parser(clap::value_parser!(u16).range(3000..))
            .action(ArgAction::Set)
            .required(true)
    );

let m = cmd.try_get_matches_from_mut(
    ["cmd", "--hostname", "rust-lang.org", "--port", "3001"]
).unwrap();

let color: &String = m.get_one("color")
    .expect("default");
assert_eq!(color, "auto");

let hostname: &String = m.get_one("hostname")
    .expect("required");
assert_eq!(hostname, "rust-lang.org");

let port: u16 = *m.get_one("port")
    .expect("required");
assert_eq!(port, 3001);

pub fn num_args(self, qty: impl IntoResettable<ValueRange>) -> Self

Specifies the number of arguments parsed per occurrence

For example, if you had a -f <file> argument where you wanted exactly 3 ‘files’ you would set .num_args(3), and this argument wouldn’t be satisfied unless the user provided 3 and only 3 values.

Users may specify values for arguments in any of the following methods

• Using a space such as -o value or --option value
• Using an equals and no space such as -o=value or --option=value
• Use a short and no space such as -ovalue

WARNING:

Setting a variable number of values (e.g. 1..=10) for an argument without other details can be dangerous in some circumstances. Because multiple values are allowed, --option val1 val2 val3 is perfectly valid. Be careful when designing a CLI where positional arguments or subcommands are also expected as clap will continue parsing values until one of the following happens:

• It reaches the maximum number of values
• It reaches a specific number of values
• It finds another flag or option (i.e. something that starts with a -)
• It reaches the Arg::value_terminator if set

Alternatively,

• Use a delimiter between values with Arg::value_delimiter
• Require a flag occurrence per value with ArgAction::Append
• Require positional arguments to appear after -- with Arg::last

Examples

Option:

let m = Command::new("prog")
    .arg(Arg::new("mode")
        .long("mode")
        .num_args(1))
    .get_matches_from(vec![
        "prog", "--mode", "fast"
    ]);

assert_eq!(m.get_one::<String>("mode").unwrap(), "fast");

Flag/option hybrid (see also default_missing_value)

let cmd = Command::new("prog")
    .arg(Arg::new("mode")
        .long("mode")
        .default_missing_value("slow")
        .default_value("plaid")
        .num_args(0..=1));

let m = cmd.clone()
    .get_matches_from(vec![
        "prog", "--mode", "fast"
    ]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "fast");

let m = cmd.clone()
    .get_matches_from(vec![
        "prog", "--mode",
    ]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "slow");

let m = cmd.clone()
    .get_matches_from(vec![
        "prog",
    ]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "plaid");

Tuples

let cmd = Command::new("prog")
    .arg(Arg::new("file")
        .action(ArgAction::Set)
        .num_args(2)
        .short('F'));

let m = cmd.clone()
    .get_matches_from(vec![
        "prog", "-F", "in-file", "out-file"
    ]);
assert_eq!(
    m.get_many::<String>("file").unwrap_or_default().map(|v| v.as_str()).collect::<Vec<_>>(),
    vec!["in-file", "out-file"]
);

let res = cmd.clone()
    .try_get_matches_from(vec![
        "prog", "-F", "file1"
    ]);
assert_eq!(res.unwrap_err().kind(), ErrorKind::WrongNumberOfValues);

A common mistake is to define an option which allows multiple values and a positional argument.

let cmd = Command::new("prog")
    .arg(Arg::new("file")
        .action(ArgAction::Set)
        .num_args(0..)
        .short('F'))
    .arg(Arg::new("word"));

let m = cmd.clone().get_matches_from(vec![
    "prog", "-F", "file1", "file2", "file3", "word"
]);
let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3", "word"]); // wait...what?!
assert!(!m.contains_id("word")); // but we clearly used word!

// but this works
let m = cmd.clone().get_matches_from(vec![
    "prog", "word", "-F", "file1", "file2", "file3",
]);
let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3"]);
assert_eq!(m.get_one::<String>("word").unwrap(), "word");

The problem is clap doesn’t know when to stop parsing values for “file”.

A solution for the example above is to limit how many values with a maximum, or specific number, or to say ArgAction::Append is ok, but multiple values are not.

let m = Command::new("prog")
    .arg(Arg::new("file")
        .action(ArgAction::Append)
        .short('F'))
    .arg(Arg::new("word"))
    .get_matches_from(vec![
        "prog", "-F", "file1", "-F", "file2", "-F", "file3", "word"
    ]);

let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3"]);
assert_eq!(m.get_one::<String>("word").unwrap(), "word");

Examples found in repository

src/builder/arg.rs (line 1106)

    pub fn number_of_values(self, qty: usize) -> Self {
        self.num_args(qty)
    }

src/builder/command.rs (line 4290)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn value_name(self, name: impl IntoResettable<Str>) -> Self

Placeholder for the argument’s value in the help message / usage.

This name is cosmetic only; the name is not used to access arguments. This setting can be very helpful when describing the type of input the user should be using, such as FILE, INTERFACE, etc. Although not required, it’s somewhat convention to use all capital letters for the value name.

NOTE: implicitly sets Arg::action(ArgAction::Set)

Examples

Arg::new("cfg")
    .long("config")
    .value_name("FILE")

let m = Command::new("prog")
   .arg(Arg::new("config")
       .long("config")
       .value_name("FILE")
       .help("Some help text"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

Running the above program produces the following output

valnames

Usage: valnames [OPTIONS]

Options:
    --config <FILE>     Some help text
    -h, --help          Print help information
    -V, --version       Print version information

Examples found in repository

src/builder/command.rs (line 4291)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn value_names(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self

Placeholders for the argument’s values in the help message / usage.

These names are cosmetic only, used for help and usage strings only. The names are not used to access arguments. The values of the arguments are accessed in numeric order (i.e. if you specify two names one and two one will be the first matched value, two will be the second).

This setting can be very helpful when describing the type of input the user should be using, such as FILE, INTERFACE, etc. Although not required, it’s somewhat convention to use all capital letters for the value name.

Pro Tip: It may help to use Arg::next_line_help(true) if there are long, or multiple value names in order to not throw off the help text alignment of all options.

NOTE: implicitly sets Arg::action(ArgAction::Set) and Arg::num_args(1..).

Examples

Arg::new("speed")
    .short('s')
    .value_names(["fast", "slow"]);

let m = Command::new("prog")
   .arg(Arg::new("io")
       .long("io-files")
       .value_names(["INFILE", "OUTFILE"]))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

Running the above program produces the following output

valnames

Usage: valnames [OPTIONS]

Options:
    -h, --help                       Print help information
    --io-files <INFILE> <OUTFILE>    Some help text
    -V, --version                    Print version information

Examples found in repository

src/builder/arg.rs (line 1158)

    pub fn value_name(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.value_names([name])
        } else {
            self.val_names.clear();
            self
        }
    }

pub fn value_hint(self, value_hint: impl IntoResettable<ValueHint>) -> Self

Provide the shell a hint about how to complete this argument.

See ValueHint for more information.

NOTE: implicitly sets [Arg::action(ArgAction::Set)].

For example, to take a username as argument:

Arg::new("user")
    .short('u')
    .long("user")
    .value_hint(ValueHint::Username);

To take a full command line and its arguments (for example, when writing a command wrapper):

Command::new("prog")
    .trailing_var_arg(true)
    .arg(
        Arg::new("command")
            .action(ArgAction::Set)
            .num_args(1..)
            .value_hint(ValueHint::CommandWithArguments)
    );

pub fn ignore_case(self, yes: bool) -> Self

Match values against PossibleValuesParser without matching case.

When other arguments are conditionally required based on the value of a case-insensitive argument, the equality check done by Arg::required_if_eq, Arg::required_if_eq_any, or Arg::required_if_eq_all is case-insensitive.

NOTE: Setting this requires taking values

NOTE: To do unicode case folding, enable the unicode feature flag.

Examples

let m = Command::new("pv")
    .arg(Arg::new("option")
        .long("option")
        .action(ArgAction::Set)
        .ignore_case(true)
        .value_parser(["test123"]))
    .get_matches_from(vec![
        "pv", "--option", "TeSt123",
    ]);

assert!(m.get_one::<String>("option").unwrap().eq_ignore_ascii_case("test123"));

This setting also works when multiple values can be defined:

let m = Command::new("pv")
    .arg(Arg::new("option")
        .short('o')
        .long("option")
        .action(ArgAction::Set)
        .ignore_case(true)
        .num_args(1..)
        .value_parser(["test123", "test321"]))
    .get_matches_from(vec![
        "pv", "--option", "TeSt123", "teST123", "tESt321"
    ]);

let matched_vals = m.get_many::<String>("option").unwrap().collect::<Vec<_>>();
assert_eq!(&*matched_vals, &["TeSt123", "teST123", "tESt321"]);

pub fn allow_hyphen_values(self, yes: bool) -> Self

Allows values which start with a leading hyphen (-)

To limit values to just numbers, see allow_negative_numbers.

See also trailing_var_arg.

NOTE: Setting this requires taking values

WARNING: Prior arguments with allow_hyphen_values(true) get precedence over known flags but known flags get precedence over the next possible positional argument with allow_hyphen_values(true). When combined with [Arg::num_args(..)], Arg::value_terminator is one way to ensure processing stops.

WARNING: Take caution when using this setting combined with another argument using Arg::num_args, as this becomes ambiguous $ prog --arg -- -- val. All three --, --, val will be values when the user may have thought the second -- would constitute the normal, “Only positional args follow” idiom.

Examples

let m = Command::new("prog")
    .arg(Arg::new("pat")
        .action(ArgAction::Set)
        .allow_hyphen_values(true)
        .long("pattern"))
    .get_matches_from(vec![
        "prog", "--pattern", "-file"
    ]);

assert_eq!(m.get_one::<String>("pat").unwrap(), "-file");

Not setting Arg::allow_hyphen_values(true) and supplying a value which starts with a hyphen is an error.

let res = Command::new("prog")
    .arg(Arg::new("pat")
        .action(ArgAction::Set)
        .long("pattern"))
    .try_get_matches_from(vec![
        "prog", "--pattern", "-file"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);

Examples found in repository

src/builder/arg.rs (line 1587)

    pub fn raw(mut self, yes: bool) -> Self {
        if yes {
            self.num_vals.get_or_insert_with(|| (1..).into());
        }
        self.allow_hyphen_values(yes).last(yes)
    }

pub fn allow_negative_numbers(self, yes: bool) -> Self

Allows negative numbers to pass as values.

This is similar to Arg::allow_hyphen_values except that it only allows numbers, all other undefined leading hyphens will fail to parse.

NOTE: Setting this requires taking values

Examples

let res = Command::new("myprog")
    .arg(Arg::new("num").allow_negative_numbers(true))
    .try_get_matches_from(vec![
        "myprog", "-20"
    ]);
assert!(res.is_ok());
let m = res.unwrap();
assert_eq!(m.get_one::<String>("num").unwrap(), "-20");

pub fn require_equals(self, yes: bool) -> Self

Requires that options use the --option=val syntax

i.e. an equals between the option and associated value.

NOTE: Setting this requires taking values

Examples

Setting require_equals requires that the option have an equals sign between it and the associated value.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .require_equals(true)
        .long("config"))
    .try_get_matches_from(vec![
        "prog", "--config=file.conf"
    ]);

assert!(res.is_ok());

Setting require_equals and not supplying the equals will cause an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .require_equals(true)
        .long("config"))
    .try_get_matches_from(vec![
        "prog", "--config", "file.conf"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::NoEquals);

pub fn value_delimiter(self, d: impl IntoResettable<char>) -> Self

Allow grouping of multiple values via a delimiter.

i.e. should --option=val1,val2,val3 be parsed as three values (val1, val2, and val3) or as a single value (val1,val2,val3). Defaults to using , (comma) as the value delimiter for all arguments that accept values (options and positional arguments)

NOTE: implicitly sets Arg::action(ArgAction::Set)

Examples

let m = Command::new("prog")
    .arg(Arg::new("config")
        .short('c')
        .long("config")
        .value_delimiter(','))
    .get_matches_from(vec![
        "prog", "--config=val1,val2,val3"
    ]);

assert_eq!(m.get_many::<String>("config").unwrap().collect::<Vec<_>>(), ["val1", "val2", "val3"])

pub fn value_terminator(self, term: impl IntoResettable<Str>) -> Self

Sentinel to stop parsing multiple values of a given argument.

By default when one sets num_args(1..) on an argument, clap will continue parsing values for that argument until it reaches another valid argument, or one of the other more specific settings for multiple values is used (such as num_args).

NOTE: This setting only applies to options and positional arguments

NOTE: When the terminator is passed in on the command line, it is not stored as one of the values

Examples

Arg::new("vals")
    .action(ArgAction::Set)
    .num_args(1..)
    .value_terminator(";")

The following example uses two arguments, a sequence of commands, and the location in which to perform them

let m = Command::new("prog")
    .arg(Arg::new("cmds")
        .action(ArgAction::Set)
        .num_args(1..)
        .allow_hyphen_values(true)
        .value_terminator(";"))
    .arg(Arg::new("location"))
    .get_matches_from(vec![
        "prog", "find", "-type", "f", "-name", "special", ";", "/home/clap"
    ]);
let cmds: Vec<_> = m.get_many::<String>("cmds").unwrap().collect();
assert_eq!(&cmds, &["find", "-type", "f", "-name", "special"]);
assert_eq!(m.get_one::<String>("location").unwrap(), "/home/clap");

pub fn raw(self, yes: bool) -> Self

Consume all following arguments.

Do not be parse them individually, but rather pass them in entirety.

It is worth noting that setting this requires all values to come after a -- to indicate they should all be captured. For example:

--foo something -- -v -v -v -b -b -b --baz -q -u -x

Will result in everything after -- to be considered one raw argument. This behavior may not be exactly what you are expecting and using crate::Command::trailing_var_arg may be more appropriate.

NOTE: Implicitly sets Arg::action(ArgAction::Set) Arg::num_args(1..), Arg::allow_hyphen_values(true), and Arg::last(true) when set to true.

pub fn default_value(self, val: impl IntoResettable<OsStr>) -> Self

Value for the argument when not present.

NOTE: If the user does not use this argument at runtime ArgMatches::contains_id will still return true. If you wish to determine whether the argument was used at runtime or not, consider ArgMatches::value_source.

NOTE: This setting is perfectly compatible with Arg::default_value_if but slightly different. Arg::default_value only takes effect when the user has not provided this arg at runtime. Arg::default_value_if however only takes effect when the user has not provided a value at runtime and these other conditions are met as well. If you have set Arg::default_value and Arg::default_value_if, and the user did not provide this arg at runtime, nor were the conditions met for Arg::default_value_if, the Arg::default_value will be applied.

NOTE: This implicitly sets Arg::action(ArgAction::Set).

Examples

First we use the default value without providing any value at runtime.

let m = Command::new("prog")
    .arg(Arg::new("opt")
        .long("myopt")
        .default_value("myval"))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_one::<String>("opt").unwrap(), "myval");
assert!(m.contains_id("opt"));
assert_eq!(m.value_source("opt"), Some(ValueSource::DefaultValue));

Next we provide a value at runtime to override the default.

let m = Command::new("prog")
    .arg(Arg::new("opt")
        .long("myopt")
        .default_value("myval"))
    .get_matches_from(vec![
        "prog", "--myopt=non_default"
    ]);

assert_eq!(m.get_one::<String>("opt").unwrap(), "non_default");
assert!(m.contains_id("opt"));
assert_eq!(m.value_source("opt"), Some(ValueSource::CommandLine));

pub fn default_values(
    self,
    vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self

Value for the argument when not present.

See Arg::default_value.

Examples found in repository

src/builder/arg.rs (line 1648)

    pub fn default_value(mut self, val: impl IntoResettable<OsStr>) -> Self {
        if let Some(val) = val.into_resettable().into_option() {
            self.default_values([val])
        } else {
            self.default_vals.clear();
            self
        }
    }

    #[inline]
    #[must_use]
    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::default_value`")
    )]
    pub fn default_value_os(self, val: impl Into<OsStr>) -> Self {
        self.default_values([val])
    }

    /// Value for the argument when not present.
    ///
    /// See [`Arg::default_value`].
    ///
    /// [`Arg::default_value`]: Arg::default_value()
    #[inline]
    #[must_use]
    pub fn default_values(mut self, vals: impl IntoIterator<Item = impl Into<OsStr>>) -> Self {
        self.default_vals = vals.into_iter().map(|s| s.into()).collect();
        self
    }

    #[inline]
    #[must_use]
    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::default_values`")
    )]
    pub fn default_values_os(self, vals: impl IntoIterator<Item = impl Into<OsStr>>) -> Self {
        self.default_values(vals)
    }

pub fn default_missing_value(self, val: impl IntoResettable<OsStr>) -> Self

Value for the argument when the flag is present but no value is specified.

This configuration option is often used to give the user a shortcut and allow them to efficiently specify an option argument without requiring an explicitly value. The --color argument is a common example. By, supplying an default, such as default_missing_value("always"), the user can quickly just add --color to the command line to produce the desired color output.

NOTE: using this configuration option requires the use of the .num_args(0..N) and the .require_equals(true) configuration option. These are required in order to unambiguously determine what, if any, value was supplied for the argument.

Examples

For POSIX style --color:

fn cli() -> Command {
    Command::new("prog")
        .arg(Arg::new("color").long("color")
            .value_name("WHEN")
            .value_parser(["always", "auto", "never"])
            .default_value("auto")
            .num_args(0..=1)
            .require_equals(true)
            .default_missing_value("always")
            .help("Specify WHEN to colorize output.")
        )
}

// first, we'll provide no arguments
let m  = cli().get_matches_from(vec![
        "prog"
    ]);
assert_eq!(m.get_one::<String>("color").unwrap(), "auto");
assert_eq!(m.value_source("color"), Some(ValueSource::DefaultValue));

// next, we'll provide a runtime value to override the default (as usually done).
let m  = cli().get_matches_from(vec![
        "prog", "--color=never"
    ]);
assert_eq!(m.get_one::<String>("color").unwrap(), "never");
assert_eq!(m.value_source("color"), Some(ValueSource::CommandLine));

// finally, we will use the shortcut and only provide the argument without a value.
let m  = cli().get_matches_from(vec![
        "prog", "--color"
    ]);
assert_eq!(m.get_one::<String>("color").unwrap(), "always");
assert_eq!(m.value_source("color"), Some(ValueSource::CommandLine));

For bool literals:

fn cli() -> Command {
    Command::new("prog")
        .arg(Arg::new("create").long("create")
            .value_name("BOOL")
            .value_parser(value_parser!(bool))
            .num_args(0..=1)
            .require_equals(true)
            .default_missing_value("true")
        )
}

// first, we'll provide no arguments
let m  = cli().get_matches_from(vec![
        "prog"
    ]);
assert_eq!(m.get_one::<bool>("create").copied(), None);

// next, we'll provide a runtime value to override the default (as usually done).
let m  = cli().get_matches_from(vec![
        "prog", "--create=false"
    ]);
assert_eq!(m.get_one::<bool>("create").copied(), Some(false));
assert_eq!(m.value_source("create"), Some(ValueSource::CommandLine));

// finally, we will use the shortcut and only provide the argument without a value.
let m  = cli().get_matches_from(vec![
        "prog", "--create"
    ]);
assert_eq!(m.get_one::<bool>("create").copied(), Some(true));
assert_eq!(m.value_source("create"), Some(ValueSource::CommandLine));

pub fn default_missing_value_os(self, val: impl Into<OsStr>) -> Self

Value for the argument when the flag is present but no value is specified.

See Arg::default_missing_value.

pub fn default_missing_values(
    self,
    vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self

Value for the argument when the flag is present but no value is specified.

See Arg::default_missing_value.

pub fn default_missing_values_os(
    self,
    vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self

Value for the argument when the flag is present but no value is specified.

See Arg::default_missing_values.

Examples found in repository

src/builder/arg.rs (line 1782)

    pub fn default_missing_value(mut self, val: impl IntoResettable<OsStr>) -> Self {
        if let Some(val) = val.into_resettable().into_option() {
            self.default_missing_values_os([val])
        } else {
            self.default_missing_vals.clear();
            self
        }
    }

    /// Value for the argument when the flag is present but no value is specified.
    ///
    /// See [`Arg::default_missing_value`].
    ///
    /// [`Arg::default_missing_value`]: Arg::default_missing_value()
    /// [`OsStr`]: std::ffi::OsStr
    #[inline]
    #[must_use]
    pub fn default_missing_value_os(self, val: impl Into<OsStr>) -> Self {
        self.default_missing_values_os([val])
    }

    /// Value for the argument when the flag is present but no value is specified.
    ///
    /// See [`Arg::default_missing_value`].
    ///
    /// [`Arg::default_missing_value`]: Arg::default_missing_value()
    #[inline]
    #[must_use]
    pub fn default_missing_values(self, vals: impl IntoIterator<Item = impl Into<OsStr>>) -> Self {
        self.default_missing_values_os(vals)
    }

pub fn env(self, name: impl IntoResettable<OsStr>) -> Self

Available on crate feature env only.

Read from name environment variable when argument is not present.

If it is not present in the environment, then default rules will apply.

If user sets the argument in the environment:

• When Arg::action(ArgAction::Set) is not set, the flag is considered raised.
• When Arg::action(ArgAction::Set) is set, ArgMatches::get_one will return value of the environment variable.

If user doesn’t set the argument in the environment:

• When Arg::action(ArgAction::Set) is not set, the flag is considered off.
• When Arg::action(ArgAction::Set) is set, ArgMatches::get_one will return the default specified.

Examples

In this example, we show the variable coming from the environment:

env::set_var("MY_FLAG", "env");

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .env("MY_FLAG")
        .action(ArgAction::Set))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_one::<String>("flag").unwrap(), "env");

In this example, because prog is a flag that accepts an optional, case-insensitive boolean literal.

Note that the value parser controls how flags are parsed. In this case we’ve selected FalseyValueParser. A false literal is n, no, f, false, off or 0. An absent environment variable will also be considered as false. Anything else will considered as true.

env::set_var("TRUE_FLAG", "true");
env::set_var("FALSE_FLAG", "0");

let m = Command::new("prog")
    .arg(Arg::new("true_flag")
        .long("true_flag")
        .action(ArgAction::SetTrue)
        .value_parser(FalseyValueParser::new())
        .env("TRUE_FLAG"))
    .arg(Arg::new("false_flag")
        .long("false_flag")
        .action(ArgAction::SetTrue)
        .value_parser(FalseyValueParser::new())
        .env("FALSE_FLAG"))
    .arg(Arg::new("absent_flag")
        .long("absent_flag")
        .action(ArgAction::SetTrue)
        .value_parser(FalseyValueParser::new())
        .env("ABSENT_FLAG"))
    .get_matches_from(vec![
        "prog"
    ]);

assert!(*m.get_one::<bool>("true_flag").unwrap());
assert!(!*m.get_one::<bool>("false_flag").unwrap());
assert!(!*m.get_one::<bool>("absent_flag").unwrap());

In this example, we show the variable coming from an option on the CLI:

env::set_var("MY_FLAG", "env");

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .env("MY_FLAG")
        .action(ArgAction::Set))
    .get_matches_from(vec![
        "prog", "--flag", "opt"
    ]);

assert_eq!(m.get_one::<String>("flag").unwrap(), "opt");

In this example, we show the variable coming from the environment even with the presence of a default:

env::set_var("MY_FLAG", "env");

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .env("MY_FLAG")
        .action(ArgAction::Set)
        .default_value("default"))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_one::<String>("flag").unwrap(), "env");

In this example, we show the use of multiple values in a single environment variable:

env::set_var("MY_FLAG_MULTI", "env1,env2");

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .env("MY_FLAG_MULTI")
        .action(ArgAction::Set)
        .num_args(1..)
        .value_delimiter(','))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_many::<String>("flag").unwrap().collect::<Vec<_>>(), vec!["env1", "env2"]);

Examples found in repository

src/builder/arg.rs (line 1993)

    pub fn env_os(self, name: impl Into<OsStr>) -> Self {
        self.env(name)
    }

impl Arg

Help

pub fn help(self, h: impl IntoResettable<StyledStr>) -> Self

Sets the description of the argument for short help (-h).

Typically, this is a short (one line) description of the arg.

If Arg::long_help is not specified, this message will be displayed for --help.

NOTE: Only Arg::help is used in completion script generation in order to be concise

Examples

Any valid UTF-8 is allowed in the help text. The one exception is when one wishes to include a newline in the help text and have the following text be properly aligned with all the other help text.

Setting help displays a short message to the side of the argument when the user passes -h or --help (by default).

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays

helptest

Usage: helptest [OPTIONS]

Options:
    --config     Some help text describing the --config arg
-h, --help       Print help information
-V, --version    Print version information

Examples found in repository

src/builder/command.rs (line 4246)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn long_help(self, h: impl IntoResettable<StyledStr>) -> Self

Sets the description of the argument for long help (--help).

Typically this a more detailed (multi-line) message that describes the arg.

If Arg::help is not specified, this message will be displayed for -h.

NOTE: Only Arg::help is used in completion script generation in order to be concise

Examples

Any valid UTF-8 is allowed in the help text. The one exception is when one wishes to include a newline in the help text and have the following text be properly aligned with all the other help text.

Setting help displays a short message to the side of the argument when the user passes -h or --help (by default).

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .long_help(
"The config file used by the myprog must be in JSON format
with only valid keys and may not contain other nonsense
that cannot be read by this program. Obviously I'm going on
and on, so I'll stop now."))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays

prog

Usage: prog [OPTIONS]

Options:
        --config
            The config file used by the myprog must be in JSON format
            with only valid keys and may not contain other nonsense
            that cannot be read by this program. Obviously I'm going on
            and on, so I'll stop now.

    -h, --help
            Print help information

    -V, --version
            Print version information

Examples found in repository

src/builder/command.rs (line 4247)

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

pub fn display_order(self, ord: impl IntoResettable<usize>) -> Self

Allows custom ordering of args within the help message.

Args with a lower value will be displayed first in the help message. This is helpful when one would like to emphasise frequently used args, or prioritize those towards the top of the list. Args with duplicate display orders will be displayed in alphabetical order.

NOTE: The default is 999 for all arguments.

NOTE: This setting is ignored for positional arguments which are always displayed in index order.

Examples

let m = Command::new("prog")
   .arg(Arg::new("a") // Typically args are grouped alphabetically by name.
                            // Args without a display_order have a value of 999 and are
                            // displayed alphabetically with all other 999 valued args.
       .long("long-option")
       .short('o')
       .action(ArgAction::Set)
       .help("Some help and text"))
   .arg(Arg::new("b")
       .long("other-option")
       .short('O')
       .action(ArgAction::Set)
       .display_order(1)   // In order to force this arg to appear *first*
                           // all we have to do is give it a value lower than 999.
                           // Any other args with a value of 1 will be displayed
                           // alphabetically with this one...then 2 values, then 3, etc.
       .help("I should be first!"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays the following help message

cust-ord

Usage: cust-ord [OPTIONS]

Options:
    -h, --help                Print help information
    -V, --version             Print version information
    -O, --other-option <b>    I should be first!
    -o, --long-option <a>     Some help and text

pub fn help_heading(self, heading: impl IntoResettable<Str>) -> Self

Override the current help section.

pub fn next_line_help(self, yes: bool) -> Self

Render the help on the line after the argument.

This can be helpful for arguments with very long or complex help messages. This can also be helpful for arguments with very long flag names, or many/long value names.

NOTE: To apply this setting to all arguments and subcommands, consider using crate::Command::next_line_help

Examples

let m = Command::new("prog")
   .arg(Arg::new("opt")
       .long("long-option-flag")
       .short('o')
       .action(ArgAction::Set)
       .next_line_help(true)
       .value_names(["value1", "value2"])
       .help("Some really long help and complex\n\
              help that makes more sense to be\n\
              on a line after the option"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays the following help message

nlh

Usage: nlh [OPTIONS]

Options:
    -h, --help       Print help information
    -V, --version    Print version information
    -o, --long-option-flag <value1> <value2>
        Some really long help and complex
        help that makes more sense to be
        on a line after the option

pub fn hide(self, yes: bool) -> Self

Do not display the argument in help message.

NOTE: This does not hide the argument from usage strings on error

Examples

Setting Hidden will hide the argument when displaying help text

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .hide(true)
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays

helptest

Usage: helptest [OPTIONS]

Options:
-h, --help       Print help information
-V, --version    Print version information

pub fn hide_possible_values(self, yes: bool) -> Self

Do not display the possible values in the help message.

This is useful for args with many values, or ones which are explained elsewhere in the help text.

NOTE: Setting this requires taking values

To set this for all arguments, see Command::hide_possible_values.

Examples

let m = Command::new("prog")
    .arg(Arg::new("mode")
        .long("mode")
        .value_parser(["fast", "slow"])
        .action(ArgAction::Set)
        .hide_possible_values(true));

If we were to run the above program with --help the [values: fast, slow] portion of the help text would be omitted.

pub fn hide_default_value(self, yes: bool) -> Self

Do not display the default value of the argument in the help message.

This is useful when default behavior of an arg is explained elsewhere in the help text.

NOTE: Setting this requires taking values

Examples

let m = Command::new("connect")
    .arg(Arg::new("host")
        .long("host")
        .default_value("localhost")
        .action(ArgAction::Set)
        .hide_default_value(true));

If we were to run the above program with --help the [default: localhost] portion of the help text would be omitted.

pub fn hide_env(self, yes: bool) -> Self

Available on crate feature env only.

Do not display in help the environment variable name.

This is useful when the variable option is explained elsewhere in the help text.

Examples

let m = Command::new("prog")
    .arg(Arg::new("mode")
        .long("mode")
        .env("MODE")
        .action(ArgAction::Set)
        .hide_env(true));

If we were to run the above program with --help the [env: MODE] portion of the help text would be omitted.

pub fn hide_env_values(self, yes: bool) -> Self

Available on crate feature env only.

Do not display in help any values inside the associated ENV variables for the argument.

This is useful when ENV vars contain sensitive values.

Examples

let m = Command::new("connect")
    .arg(Arg::new("host")
        .long("host")
        .env("CONNECT")
        .action(ArgAction::Set)
        .hide_env_values(true));

If we were to run the above program with $ CONNECT=super_secret connect --help the [default: CONNECT=super_secret] portion of the help text would be omitted.

pub fn hide_short_help(self, yes: bool) -> Self

Hides an argument from short help (-h).

NOTE: This does not hide the argument from usage strings on error

NOTE: Setting this option will cause next-line-help output style to be used when long help (--help) is called.

Examples

Arg::new("debug")
    .hide_short_help(true);

Setting hide_short_help(true) will hide the argument when displaying short help text

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .hide_short_help(true)
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "-h"
   ]);

The above example displays

helptest

Usage: helptest [OPTIONS]

Options:
-h, --help       Print help information
-V, --version    Print version information

However, when –help is called

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .hide_short_help(true)
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

Then the following would be displayed

helptest

Usage: helptest [OPTIONS]

Options:
    --config     Some help text describing the --config arg
-h, --help       Print help information
-V, --version    Print version information

pub fn hide_long_help(self, yes: bool) -> Self

Hides an argument from long help (--help).

NOTE: This does not hide the argument from usage strings on error

NOTE: Setting this option will cause next-line-help output style to be used when long help (--help) is called.

Examples

Setting hide_long_help(true) will hide the argument when displaying long help text

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .hide_long_help(true)
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "--help"
   ]);

The above example displays

helptest

Usage: helptest [OPTIONS]

Options:
-h, --help       Print help information
-V, --version    Print version information

However, when -h is called

let m = Command::new("prog")
   .arg(Arg::new("cfg")
       .long("config")
       .hide_long_help(true)
       .help("Some help text describing the --config arg"))
   .get_matches_from(vec![
       "prog", "-h"
   ]);

Then the following would be displayed

helptest

Usage: helptest [OPTIONS]

OPTIONS:
    --config     Some help text describing the --config arg
-h, --help       Print help information
-V, --version    Print version information

impl Arg

Advanced Argument Relations

pub fn group(self, group_id: impl IntoResettable<Id>) -> Self

The name of the ArgGroup the argument belongs to.

Examples

Arg::new("debug")
    .long("debug")
    .action(ArgAction::SetTrue)
    .group("mode")

Multiple arguments can be a member of a single group and then the group checked as if it was one of said arguments.

let m = Command::new("prog")
    .arg(Arg::new("debug")
        .long("debug")
        .action(ArgAction::SetTrue)
        .group("mode"))
    .arg(Arg::new("verbose")
        .long("verbose")
        .action(ArgAction::SetTrue)
        .group("mode"))
    .get_matches_from(vec![
        "prog", "--debug"
    ]);
assert!(m.contains_id("mode"));

pub fn groups(self, group_ids: impl IntoIterator<Item = impl Into<Id>>) -> Self

The names of ArgGroup’s the argument belongs to.

Examples

Arg::new("debug")
    .long("debug")
    .action(ArgAction::SetTrue)
    .groups(["mode", "verbosity"])

Arguments can be members of multiple groups and then the group checked as if it was one of said arguments.

let m = Command::new("prog")
    .arg(Arg::new("debug")
        .long("debug")
        .action(ArgAction::SetTrue)
        .groups(["mode", "verbosity"]))
    .arg(Arg::new("verbose")
        .long("verbose")
        .action(ArgAction::SetTrue)
        .groups(["mode", "verbosity"]))
    .get_matches_from(vec![
        "prog", "--debug"
    ]);
assert!(m.contains_id("mode"));
assert!(m.contains_id("verbosity"));

pub fn default_value_if(
    self,
    arg_id: impl Into<Id>,
    predicate: impl Into<ArgPredicate>,
    default: impl IntoResettable<OsStr>
) -> Self

Specifies the value of the argument if arg has been used at runtime.

If default is set to None, default_value will be removed.

NOTE: This setting is perfectly compatible with Arg::default_value but slightly different. Arg::default_value only takes effect when the user has not provided this arg at runtime. This setting however only takes effect when the user has not provided a value at runtime and these other conditions are met as well. If you have set Arg::default_value and Arg::default_value_if, and the user did not provide this arg at runtime, nor were the conditions met for Arg::default_value_if, the Arg::default_value will be applied.

NOTE: This implicitly sets Arg::action(ArgAction::Set).

Examples

First we use the default value only if another arg is present at runtime.

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("other")
        .long("other")
        .default_value_if("flag", ArgPredicate::IsPresent, Some("default")))
    .get_matches_from(vec![
        "prog", "--flag"
    ]);

assert_eq!(m.get_one::<String>("other").unwrap(), "default");

Next we run the same test, but without providing --flag.

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("other")
        .long("other")
        .default_value_if("flag", "true", Some("default")))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_one::<String>("other"), None);

Now lets only use the default value if --opt contains the value special.

let m = Command::new("prog")
    .arg(Arg::new("opt")
        .action(ArgAction::Set)
        .long("opt"))
    .arg(Arg::new("other")
        .long("other")
        .default_value_if("opt", "special", Some("default")))
    .get_matches_from(vec![
        "prog", "--opt", "special"
    ]);

assert_eq!(m.get_one::<String>("other").unwrap(), "default");

We can run the same test and provide any value other than special and we won’t get a default value.

let m = Command::new("prog")
    .arg(Arg::new("opt")
        .action(ArgAction::Set)
        .long("opt"))
    .arg(Arg::new("other")
        .long("other")
        .default_value_if("opt", "special", Some("default")))
    .get_matches_from(vec![
        "prog", "--opt", "hahaha"
    ]);

assert_eq!(m.get_one::<String>("other"), None);

If we want to unset the default value for an Arg based on the presence or value of some other Arg.

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("other")
        .long("other")
        .default_value("default")
        .default_value_if("flag", "true", None))
    .get_matches_from(vec![
        "prog", "--flag"
    ]);

assert_eq!(m.get_one::<String>("other"), None);

Examples found in repository

src/builder/arg.rs (line 2775)

    pub fn default_value_if_os(
        self,
        arg_id: impl Into<Id>,
        predicate: impl Into<ArgPredicate>,
        default: impl IntoResettable<OsStr>,
    ) -> Self {
        self.default_value_if(arg_id, predicate, default)
    }

    /// Specifies multiple values and conditions in the same manner as [`Arg::default_value_if`].
    ///
    /// The method takes a slice of tuples in the `(arg, predicate, default)` format.
    ///
    /// **NOTE**: The conditions are stored in order and evaluated in the same order. I.e. the first
    /// if multiple conditions are true, the first one found will be applied and the ultimate value.
    ///
    /// # Examples
    ///
    /// First we use the default value only if another arg is present at runtime.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("prog")
    ///     .arg(Arg::new("flag")
    ///         .long("flag")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("opt")
    ///         .long("opt")
    ///         .action(ArgAction::Set))
    ///     .arg(Arg::new("other")
    ///         .long("other")
    ///         .default_value_ifs([
    ///             ("flag", "true", Some("default")),
    ///             ("opt", "channal", Some("chan")),
    ///         ]))
    ///     .get_matches_from(vec![
    ///         "prog", "--opt", "channal"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("other").unwrap(), "chan");
    /// ```
    ///
    /// Next we run the same test, but without providing `--flag`.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("prog")
    ///     .arg(Arg::new("flag")
    ///         .long("flag")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("other")
    ///         .long("other")
    ///         .default_value_ifs([
    ///             ("flag", "true", Some("default")),
    ///             ("opt", "channal", Some("chan")),
    ///         ]))
    ///     .get_matches_from(vec![
    ///         "prog"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("other"), None);
    /// ```
    ///
    /// We can also see that these values are applied in order, and if more than one condition is
    /// true, only the first evaluated "wins"
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// # use clap::builder::ArgPredicate;
    /// let m = Command::new("prog")
    ///     .arg(Arg::new("flag")
    ///         .long("flag")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("opt")
    ///         .long("opt")
    ///         .action(ArgAction::Set))
    ///     .arg(Arg::new("other")
    ///         .long("other")
    ///         .default_value_ifs([
    ///             ("flag", ArgPredicate::IsPresent, Some("default")),
    ///             ("opt", ArgPredicate::Equals("channal".into()), Some("chan")),
    ///         ]))
    ///     .get_matches_from(vec![
    ///         "prog", "--opt", "channal", "--flag"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("other").unwrap(), "default");
    /// ```
    /// [`Arg::action(ArgAction::Set)`]: Arg::action()
    /// [`Arg::default_value_if`]: Arg::default_value_if()
    #[must_use]
    pub fn default_value_ifs(
        mut self,
        ifs: impl IntoIterator<
            Item = (
                impl Into<Id>,
                impl Into<ArgPredicate>,
                impl IntoResettable<OsStr>,
            ),
        >,
    ) -> Self {
        for (arg, predicate, default) in ifs {
            self = self.default_value_if(arg, predicate, default);
        }
        self
    }

pub fn default_value_ifs(
    self,
    ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<ArgPredicate>, impl IntoResettable<OsStr>)>
) -> Self

Specifies multiple values and conditions in the same manner as Arg::default_value_if.

The method takes a slice of tuples in the (arg, predicate, default) format.

NOTE: The conditions are stored in order and evaluated in the same order. I.e. the first if multiple conditions are true, the first one found will be applied and the ultimate value.

Examples

First we use the default value only if another arg is present at runtime.

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("opt")
        .long("opt")
        .action(ArgAction::Set))
    .arg(Arg::new("other")
        .long("other")
        .default_value_ifs([
            ("flag", "true", Some("default")),
            ("opt", "channal", Some("chan")),
        ]))
    .get_matches_from(vec![
        "prog", "--opt", "channal"
    ]);

assert_eq!(m.get_one::<String>("other").unwrap(), "chan");

Next we run the same test, but without providing --flag.

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("other")
        .long("other")
        .default_value_ifs([
            ("flag", "true", Some("default")),
            ("opt", "channal", Some("chan")),
        ]))
    .get_matches_from(vec![
        "prog"
    ]);

assert_eq!(m.get_one::<String>("other"), None);

We can also see that these values are applied in order, and if more than one condition is true, only the first evaluated “wins”

let m = Command::new("prog")
    .arg(Arg::new("flag")
        .long("flag")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("opt")
        .long("opt")
        .action(ArgAction::Set))
    .arg(Arg::new("other")
        .long("other")
        .default_value_ifs([
            ("flag", ArgPredicate::IsPresent, Some("default")),
            ("opt", ArgPredicate::Equals("channal".into()), Some("chan")),
        ]))
    .get_matches_from(vec![
        "prog", "--opt", "channal", "--flag"
    ]);

assert_eq!(m.get_one::<String>("other").unwrap(), "default");

Examples found in repository

src/builder/arg.rs (line 2892)

    pub fn default_value_ifs_os(
        self,
        ifs: impl IntoIterator<
            Item = (
                impl Into<Id>,
                impl Into<ArgPredicate>,
                impl IntoResettable<OsStr>,
            ),
        >,
    ) -> Self {
        self.default_value_ifs(ifs)
    }

pub fn required_unless_present(self, arg_id: impl IntoResettable<Id>) -> Self

Set this arg as required as long as the specified argument is not present at runtime.

Pro Tip: Using Arg::required_unless_present implies Arg::required and is therefore not mandatory to also set.

Examples

Arg::new("config")
    .required_unless_present("debug")

In the following example, the required argument is not provided, but it’s not an error because the unless arg has been supplied.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present("dbg")
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug")
        .action(ArgAction::SetTrue))
    .try_get_matches_from(vec![
        "prog", "--debug"
    ]);

assert!(res.is_ok());

Setting Arg::required_unless_present(name) and not supplying name or this arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present("dbg")
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug"))
    .try_get_matches_from(vec![
        "prog"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn required_unless_present_all(
    self,
    names: impl IntoIterator<Item = impl Into<Id>>
) -> Self

Sets this arg as required unless all of the specified arguments are present at runtime.

In other words, parsing will succeed only if user either

• supplies the self arg.
• supplies all of the names arguments.

NOTE: If you wish for this argument to only be required unless any of these args are present see Arg::required_unless_present_any

Examples

Arg::new("config")
    .required_unless_present_all(["cfg", "dbg"])

In the following example, the required argument is not provided, but it’s not an error because all of the names args have been supplied.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present_all(["dbg", "infile"])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("infile")
        .short('i')
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--debug", "-i", "file"
    ]);

assert!(res.is_ok());

Setting Arg::required_unless_present_all(names) and not supplying either all of unless args or the self arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present_all(["dbg", "infile"])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("infile")
        .short('i')
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn required_unless_present_any(
    self,
    names: impl IntoIterator<Item = impl Into<Id>>
) -> Self

Sets this arg as required unless any of the specified arguments are present at runtime.

In other words, parsing will succeed only if user either

• supplies the self arg.
• supplies one or more of the unless arguments.

NOTE: If you wish for this argument to be required unless all of these args are present see Arg::required_unless_present_all

Examples

Arg::new("config")
    .required_unless_present_any(["cfg", "dbg"])

Setting Arg::required_unless_present_any(names) requires that the argument be used at runtime unless at least one of the args in names are present. In the following example, the required argument is not provided, but it’s not an error because one the unless args have been supplied.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present_any(["dbg", "infile"])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("infile")
        .short('i')
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--debug"
    ]);

assert!(res.is_ok());

Setting Arg::required_unless_present_any(names) and not supplying at least one of names or this arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_unless_present_any(["dbg", "infile"])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("dbg")
        .long("debug")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("infile")
        .short('i')
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn required_if_eq(self, arg_id: impl Into<Id>, val: impl Into<OsStr>) -> Self

This argument is required only if the specified arg is present at runtime and its value equals val.

Examples

Arg::new("config")
    .required_if_eq("other_arg", "value")

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .required_if_eq("other", "special")
        .long("config"))
    .arg(Arg::new("other")
        .long("other")
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--other", "not-special"
    ]);

assert!(res.is_ok()); // We didn't use --other=special, so "cfg" wasn't required

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .required_if_eq("other", "special")
        .long("config"))
    .arg(Arg::new("other")
        .long("other")
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--other", "special"
    ]);

// We did use --other=special so "cfg" had become required but was missing.
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .required_if_eq("other", "special")
        .long("config"))
    .arg(Arg::new("other")
        .long("other")
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--other", "SPECIAL"
    ]);

// By default, the comparison is case-sensitive, so "cfg" wasn't required
assert!(res.is_ok());

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .required_if_eq("other", "special")
        .long("config"))
    .arg(Arg::new("other")
        .long("other")
        .ignore_case(true)
        .action(ArgAction::Set))
    .try_get_matches_from(vec![
        "prog", "--other", "SPECIAL"
    ]);

// However, case-insensitive comparisons can be enabled.  This typically occurs when using Arg::possible_values().
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn required_if_eq_any(
    self,
    ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self

Specify this argument is required based on multiple conditions.

The conditions are set up in a (arg, val) style tuple. The requirement will only become valid if one of the specified arg’s value equals its corresponding val.

Examples

Arg::new("config")
    .required_if_eq_any([
        ("extra", "val"),
        ("option", "spec")
    ])

Setting Arg::required_if_eq_any([(arg, val)]) makes this arg required if any of the args are used at runtime and it’s corresponding value is equal to val. If the arg’s value is anything other than val, this argument isn’t required.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_if_eq_any([
            ("extra", "val"),
            ("option", "spec")
        ])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("extra")
        .action(ArgAction::Set)
        .long("extra"))
    .arg(Arg::new("option")
        .action(ArgAction::Set)
        .long("option"))
    .try_get_matches_from(vec![
        "prog", "--option", "other"
    ]);

assert!(res.is_ok()); // We didn't use --option=spec, or --extra=val so "cfg" isn't required

Setting Arg::required_if_eq_any([(arg, val)]) and having any of the args used with its value of val but not using this arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_if_eq_any([
            ("extra", "val"),
            ("option", "spec")
        ])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("extra")
        .action(ArgAction::Set)
        .long("extra"))
    .arg(Arg::new("option")
        .action(ArgAction::Set)
        .long("option"))
    .try_get_matches_from(vec![
        "prog", "--option", "spec"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn required_if_eq_all(
    self,
    ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self

Specify this argument is required based on multiple conditions.

The conditions are set up in a (arg, val) style tuple. The requirement will only become valid if every one of the specified arg’s value equals its corresponding val.

Examples

Arg::new("config")
    .required_if_eq_all([
        ("extra", "val"),
        ("option", "spec")
    ])

Setting Arg::required_if_eq_all([(arg, val)]) makes this arg required if all of the args are used at runtime and every value is equal to its corresponding val. If the arg’s value is anything other than val, this argument isn’t required.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_if_eq_all([
            ("extra", "val"),
            ("option", "spec")
        ])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("extra")
        .action(ArgAction::Set)
        .long("extra"))
    .arg(Arg::new("option")
        .action(ArgAction::Set)
        .long("option"))
    .try_get_matches_from(vec![
        "prog", "--option", "spec"
    ]);

assert!(res.is_ok()); // We didn't use --option=spec --extra=val so "cfg" isn't required

Setting Arg::required_if_eq_all([(arg, val)]) and having all of the args used with its value of val but not using this arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .required_if_eq_all([
            ("extra", "val"),
            ("option", "spec")
        ])
        .action(ArgAction::Set)
        .long("config"))
    .arg(Arg::new("extra")
        .action(ArgAction::Set)
        .long("extra"))
    .arg(Arg::new("option")
        .action(ArgAction::Set)
        .long("option"))
    .try_get_matches_from(vec![
        "prog", "--extra", "val", "--option", "spec"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn requires_if(
    self,
    val: impl Into<ArgPredicate>,
    arg_id: impl Into<Id>
) -> Self

Require another argument if this arg matches the ArgPredicate

This method takes value, another_arg pair. At runtime, clap will check if this arg (self) matches the ArgPredicate. If it does, another_arg will be marked as required.

Examples

Arg::new("config")
    .requires_if("val", "arg")

Setting Arg::requires_if(val, arg) requires that the arg be used at runtime if the defining argument’s value is equal to val. If the defining argument is anything other than val, the other argument isn’t required.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires_if("my.cfg", "other")
        .long("config"))
    .arg(Arg::new("other"))
    .try_get_matches_from(vec![
        "prog", "--config", "some.cfg"
    ]);

assert!(res.is_ok()); // We didn't use --config=my.cfg, so other wasn't required

Setting Arg::requires_if(val, arg) and setting the value to val but not supplying arg is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires_if("my.cfg", "input")
        .long("config"))
    .arg(Arg::new("input"))
    .try_get_matches_from(vec![
        "prog", "--config", "my.cfg"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

pub fn requires_ifs(
    self,
    ifs: impl IntoIterator<Item = (impl Into<ArgPredicate>, impl Into<Id>)>
) -> Self

Allows multiple conditional requirements.

The requirement will only become valid if this arg’s value matches the ArgPredicate.

Examples

Arg::new("config")
    .requires_ifs([
        ("val", "arg"),
        ("other_val", "arg2"),
    ])

Setting Arg::requires_ifs(["val", "arg"]) requires that the arg be used at runtime if the defining argument’s value is equal to val. If the defining argument’s value is anything other than val, arg isn’t required.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires_ifs([
            ("special.conf", "opt"),
            ("other.conf", "other"),
        ])
        .long("config"))
    .arg(Arg::new("opt")
        .long("option")
        .action(ArgAction::Set))
    .arg(Arg::new("other"))
    .try_get_matches_from(vec![
        "prog", "--config", "special.conf"
    ]);

assert!(res.is_err()); // We  used --config=special.conf so --option <val> is required
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

Setting Arg::requires_ifs with ArgPredicate::IsPresent and not supplying all the arguments is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .requires_ifs([
            (ArgPredicate::IsPresent, "input"),
            (ArgPredicate::IsPresent, "output"),
        ])
        .long("config"))
    .arg(Arg::new("input"))
    .arg(Arg::new("output"))
    .try_get_matches_from(vec![
        "prog", "--config", "file.conf", "in.txt"
    ]);

assert!(res.is_err());
// We didn't use output
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

Examples found in repository

src/builder/arg.rs (line 3508)

    pub fn requires_all(self, ids: impl IntoIterator<Item = impl Into<Id>>) -> Self {
        self.requires_ifs(ids.into_iter().map(|id| (ArgPredicate::IsPresent, id)))
    }

pub fn conflicts_with(self, arg_id: impl IntoResettable<Id>) -> Self

This argument is mutually exclusive with the specified argument.

NOTE: Conflicting rules take precedence over being required by default. Conflict rules only need to be set for one of the two arguments, they do not need to be set for each.

NOTE: Defining a conflict is two-way, but does not need to defined for both arguments (i.e. if A conflicts with B, defining A.conflicts_with(B) is sufficient. You do not need to also do B.conflicts_with(A))

NOTE: Arg::conflicts_with_all(names) allows specifying an argument which conflicts with more than one argument.

NOTE Arg::exclusive(true) allows specifying an argument which conflicts with every other argument.

NOTE: All arguments implicitly conflict with themselves.

Examples

Arg::new("config")
    .conflicts_with("debug")

Setting conflicting argument, and having both arguments present at runtime is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .conflicts_with("debug")
        .long("config"))
    .arg(Arg::new("debug")
        .long("debug")
        .action(ArgAction::SetTrue))
    .try_get_matches_from(vec![
        "prog", "--debug", "--config", "file.conf"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);

pub fn conflicts_with_all(
    self,
    names: impl IntoIterator<Item = impl Into<Id>>
) -> Self

This argument is mutually exclusive with the specified arguments.

See Arg::conflicts_with.

NOTE: Conflicting rules take precedence over being required by default. Conflict rules only need to be set for one of the two arguments, they do not need to be set for each.

NOTE: Defining a conflict is two-way, but does not need to defined for both arguments (i.e. if A conflicts with B, defining A.conflicts_with(B) is sufficient. You do not need need to also do B.conflicts_with(A))

NOTE: Arg::exclusive(true) allows specifying an argument which conflicts with every other argument.

Examples

Arg::new("config")
    .conflicts_with_all(["debug", "input"])

Setting conflicting argument, and having any of the arguments present at runtime with a conflicting argument is an error.

let res = Command::new("prog")
    .arg(Arg::new("cfg")
        .action(ArgAction::Set)
        .conflicts_with_all(["debug", "input"])
        .long("config"))
    .arg(Arg::new("debug")
        .long("debug"))
    .arg(Arg::new("input"))
    .try_get_matches_from(vec![
        "prog", "--config", "file.conf", "file.txt"
    ]);

assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);

pub fn overrides_with(self, arg_id: impl IntoResettable<Id>) -> Self

Sets an overridable argument.

i.e. this argument and the following argument will override each other in POSIX style (whichever argument was specified at runtime last “wins”)

NOTE: When an argument is overridden it is essentially as if it never was used, any conflicts, requirements, etc. are evaluated after all “overrides” have been removed

NOTE: Overriding an argument implies they conflict.

Examples

let m = Command::new("prog")
    .arg(arg!(-f --flag "some flag")
        .conflicts_with("debug"))
    .arg(arg!(-d --debug "other flag"))
    .arg(arg!(-c --color "third flag")
        .overrides_with("flag"))
    .get_matches_from(vec![
        "prog", "-f", "-d", "-c"]);
            //    ^~~~~~~~~~~~^~~~~ flag is overridden by color

assert!(*m.get_one::<bool>("color").unwrap());
assert!(*m.get_one::<bool>("debug").unwrap()); // even though flag conflicts with debug, it's as if flag
                                // was never used because it was overridden with color
assert!(!*m.get_one::<bool>("flag").unwrap());

pub fn overrides_with_all(
    self,
    names: impl IntoIterator<Item = impl Into<Id>>
) -> Self

Sets multiple mutually overridable arguments by name.

i.e. this argument and the following argument will override each other in POSIX style (whichever argument was specified at runtime last “wins”)

NOTE: When an argument is overridden it is essentially as if it never was used, any conflicts, requirements, etc. are evaluated after all “overrides” have been removed

NOTE: Overriding an argument implies they conflict.

Examples

let m = Command::new("prog")
    .arg(arg!(-f --flag "some flag")
        .conflicts_with("color"))
    .arg(arg!(-d --debug "other flag"))
    .arg(arg!(-c --color "third flag")
        .overrides_with_all(["flag", "debug"]))
    .get_matches_from(vec![
        "prog", "-f", "-d", "-c"]);
            //    ^~~~~~^~~~~~~~~ flag and debug are overridden by color

assert!(*m.get_one::<bool>("color").unwrap()); // even though flag conflicts with color, it's as if flag
                                // and debug were never used because they were overridden
                                // with color
assert!(!*m.get_one::<bool>("debug").unwrap());
assert!(!*m.get_one::<bool>("flag").unwrap());

impl Arg

Reflection

pub fn get_id(&self) -> &Id

Get the name of the argument

Examples found in repository

src/parser/arg_matcher.rs (line 28)

    pub(crate) fn new(_cmd: &Command) -> Self {
        ArgMatcher {
            matches: ArgMatches {
                #[cfg(debug_assertions)]
                valid_args: {
                    let args = _cmd.get_arguments().map(|a| a.get_id().clone());
                    let groups = _cmd.get_groups().map(|g| g.get_id().clone());
                    args.chain(groups).collect()
                },
                #[cfg(debug_assertions)]
                valid_subcommands: _cmd
                    .get_subcommands()
                    .map(|sc| sc.get_name_str().clone())
                    .collect(),
                ..Default::default()
            },
            pending: None,
        }
    }

    pub(crate) fn into_inner(self) -> ArgMatches {
        self.matches
    }

    pub(crate) fn propagate_globals(&mut self, global_arg_vec: &[Id]) {
        debug!(
            "ArgMatcher::get_global_values: global_arg_vec={:?}",
            global_arg_vec
        );
        let mut vals_map = FlatMap::new();
        self.fill_in_global_values(global_arg_vec, &mut vals_map);
    }

    fn fill_in_global_values(
        &mut self,
        global_arg_vec: &[Id],
        vals_map: &mut FlatMap<Id, MatchedArg>,
    ) {
        for global_arg in global_arg_vec {
            if let Some(ma) = self.get(global_arg) {
                // We have to check if the parent's global arg wasn't used but still exists
                // such as from a default value.
                //
                // For example, `myprog subcommand --global-arg=value` where `--global-arg` defines
                // a default value of `other` myprog would have an existing MatchedArg for
                // `--global-arg` where the value is `other`
                let to_update = if let Some(parent_ma) = vals_map.get(global_arg) {
                    if parent_ma.source() > ma.source() {
                        parent_ma
                    } else {
                        ma
                    }
                } else {
                    ma
                }
                .clone();
                vals_map.insert(global_arg.clone(), to_update);
            }
        }
        if let Some(ref mut sc) = self.matches.subcommand {
            let mut am = ArgMatcher {
                matches: mem::take(&mut sc.matches),
                pending: None,
            };
            am.fill_in_global_values(global_arg_vec, vals_map);
            mem::swap(&mut am.matches, &mut sc.matches);
        }

        for (name, matched_arg) in vals_map.iter_mut() {
            self.matches.args.insert(name.clone(), matched_arg.clone());
        }
    }

    pub(crate) fn get(&self, arg: &Id) -> Option<&MatchedArg> {
        self.matches.args.get(arg)
    }

    pub(crate) fn get_mut(&mut self, arg: &Id) -> Option<&mut MatchedArg> {
        self.matches.args.get_mut(arg)
    }

    pub(crate) fn remove(&mut self, arg: &Id) -> bool {
        self.matches.args.remove(arg).is_some()
    }

    pub(crate) fn contains(&self, arg: &Id) -> bool {
        self.matches.args.contains_key(arg)
    }

    pub(crate) fn arg_ids(&self) -> std::slice::Iter<'_, Id> {
        self.matches.args.keys()
    }

    pub(crate) fn entry(&mut self, arg: Id) -> crate::util::Entry<Id, MatchedArg> {
        self.matches.args.entry(arg)
    }

    pub(crate) fn subcommand(&mut self, sc: SubCommand) {
        self.matches.subcommand = Some(Box::new(sc));
    }

    pub(crate) fn subcommand_name(&self) -> Option<&str> {
        self.matches.subcommand_name()
    }

    pub(crate) fn check_explicit(&self, arg: &Id, predicate: &ArgPredicate) -> bool {
        self.get(arg).map_or(false, |a| a.check_explicit(predicate))
    }

    pub(crate) fn start_custom_arg(&mut self, arg: &Arg, source: ValueSource) {
        let id = arg.get_id().clone();
        debug!(
            "ArgMatcher::start_custom_arg: id={:?}, source={:?}",
            id, source
        );
        let ma = self.entry(id).or_insert(MatchedArg::new_arg(arg));
        debug_assert_eq!(ma.type_id(), Some(arg.get_value_parser().type_id()));
        ma.set_source(source);
        ma.new_val_group();
    }

    pub(crate) fn start_custom_group(&mut self, id: Id, source: ValueSource) {
        debug!(
            "ArgMatcher::start_custom_arg: id={:?}, source={:?}",
            id, source
        );
        let ma = self.entry(id).or_insert(MatchedArg::new_group());
        debug_assert_eq!(ma.type_id(), None);
        ma.set_source(source);
        ma.new_val_group();
    }

    pub(crate) fn start_occurrence_of_external(&mut self, cmd: &crate::Command) {
        let id = Id::from_static_ref(Id::EXTERNAL);
        debug!("ArgMatcher::start_occurrence_of_external: id={:?}", id,);
        let ma = self.entry(id).or_insert(MatchedArg::new_external(cmd));
        debug_assert_eq!(
            ma.type_id(),
            Some(
                cmd.get_external_subcommand_value_parser()
                    .expect(INTERNAL_ERROR_MSG)
                    .type_id()
            )
        );
        ma.set_source(ValueSource::CommandLine);
        ma.new_val_group();
    }

    pub(crate) fn add_val_to(&mut self, arg: &Id, val: AnyValue, raw_val: OsString) {
        let ma = self.get_mut(arg).expect(INTERNAL_ERROR_MSG);
        ma.append_val(val, raw_val);
    }

    pub(crate) fn add_index_to(&mut self, arg: &Id, idx: usize) {
        let ma = self.get_mut(arg).expect(INTERNAL_ERROR_MSG);
        ma.push_index(idx);
    }

    pub(crate) fn needs_more_vals(&self, o: &Arg) -> bool {
        let num_pending = self
            .pending
            .as_ref()
            .and_then(|p| (p.id == *o.get_id()).then(|| p.raw_vals.len()))
            .unwrap_or(0);
        debug!(
            "ArgMatcher::needs_more_vals: o={}, pending={}",
            o.get_id(),
            num_pending
        );
        let expected = o.get_num_args().expect(INTERNAL_ERROR_MSG);
        debug!(
            "ArgMatcher::needs_more_vals: expected={}, actual={}",
            expected, num_pending
        );
        expected.accepts_more(num_pending)
    }

src/builder/command.rs (line 3523)

    fn get_global_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        arg.blacklist
            .iter()
            .map(|id| {
                self.args
                    .args()
                    .chain(
                        self.get_subcommands_containing(arg)
                            .iter()
                            .flat_map(|x| x.args.args()),
                    )
                    .find(|arg| arg.get_id() == id)
                    .expect(
                        "Command::get_arg_conflicts_with: \
                    The passed arg conflicts with an arg unknown to the cmd",
                    )
            })
            .collect()
    }

    // Get a list of subcommands which contain the provided Argument
    //
    // This command will only include subcommands in its list for which the subcommands
    // parent also contains the Argument.
    //
    // This search follows the propagation rules of global arguments.
    // It is useful to finding subcommands, that have inherited a global argument.
    //
    // **NOTE:** In this case only Sucommand_1 will be included
    //   Subcommand_1 (contains Arg)
    //     Subcommand_1.1 (doesn't contain Arg)
    //       Subcommand_1.1.1 (contains Arg)
    //
    fn get_subcommands_containing(&self, arg: &Arg) -> Vec<&Self> {
        let mut vec = std::vec::Vec::new();
        for idx in 0..self.subcommands.len() {
            if self.subcommands[idx]
                .args
                .args()
                .any(|ar| ar.get_id() == arg.get_id())
            {
                vec.push(&self.subcommands[idx]);
                vec.append(&mut self.subcommands[idx].get_subcommands_containing(arg));
            }
        }
        vec
    }

    /// Report whether [`Command::no_binary_name`] is set
    pub fn is_no_binary_name_set(&self) -> bool {
        self.is_set(AppSettings::NoBinaryName)
    }

    /// Report whether [`Command::ignore_errors`] is set
    pub(crate) fn is_ignore_errors_set(&self) -> bool {
        self.is_set(AppSettings::IgnoreErrors)
    }

    /// Report whether [`Command::dont_delimit_trailing_values`] is set
    pub fn is_dont_delimit_trailing_values_set(&self) -> bool {
        self.is_set(AppSettings::DontDelimitTrailingValues)
    }

    /// Report whether [`Command::disable_version_flag`] is set
    pub fn is_disable_version_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableVersionFlag)
            || (self.version.is_none() && self.long_version.is_none())
    }

    /// Report whether [`Command::propagate_version`] is set
    pub fn is_propagate_version_set(&self) -> bool {
        self.is_set(AppSettings::PropagateVersion)
    }

    /// Report whether [`Command::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(AppSettings::NextLineHelp)
    }

    /// Report whether [`Command::disable_help_flag`] is set
    pub fn is_disable_help_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpFlag)
    }

    /// Report whether [`Command::disable_help_subcommand`] is set
    pub fn is_disable_help_subcommand_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpSubcommand)
    }

    /// Report whether [`Command::disable_colored_help`] is set
    pub fn is_disable_colored_help_set(&self) -> bool {
        self.is_set(AppSettings::DisableColoredHelp)
    }

    /// Report whether [`Command::help_expected`] is set
    #[cfg(debug_assertions)]
    pub(crate) fn is_help_expected_set(&self) -> bool {
        self.is_set(AppSettings::HelpExpected)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn is_dont_collapse_args_in_usage_set(&self) -> bool {
        true
    }

    /// Report whether [`Command::infer_long_args`] is set
    pub(crate) fn is_infer_long_args_set(&self) -> bool {
        self.is_set(AppSettings::InferLongArgs)
    }

    /// Report whether [`Command::infer_subcommands`] is set
    pub(crate) fn is_infer_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::InferSubcommands)
    }

    /// Report whether [`Command::arg_required_else_help`] is set
    pub fn is_arg_required_else_help_set(&self) -> bool {
        self.is_set(AppSettings::ArgRequiredElseHelp)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_hyphen_values_set`"
        )
    )]
    pub(crate) fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(AppSettings::AllowHyphenValues)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_negative_numbers_set`"
        )
    )]
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(AppSettings::AllowNegativeNumbers)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::is_trailing_var_arg_set`")
    )]
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(AppSettings::TrailingVarArg)
    }

    /// Report whether [`Command::allow_missing_positional`] is set
    pub fn is_allow_missing_positional_set(&self) -> bool {
        self.is_set(AppSettings::AllowMissingPositional)
    }

    /// Report whether [`Command::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(AppSettings::Hidden)
    }

    /// Report whether [`Command::subcommand_required`] is set
    pub fn is_subcommand_required_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandRequired)
    }

    /// Report whether [`Command::allow_external_subcommands`] is set
    pub fn is_allow_external_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::AllowExternalSubcommands)
    }

    /// Configured parser for values passed to an external subcommand
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .external_subcommand_value_parser(clap::value_parser!(String));
    /// let value_parser = cmd.get_external_subcommand_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_external_subcommand_value_parser(&self) -> Option<&super::ValueParser> {
        if !self.is_allow_external_subcommands_set() {
            None
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::os_string();
            Some(self.external_value_parser.as_ref().unwrap_or(&DEFAULT))
        }
    }

    /// Report whether [`Command::args_conflicts_with_subcommands`] is set
    pub fn is_args_conflicts_with_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::ArgsNegateSubcommands)
    }

    #[doc(hidden)]
    pub fn is_args_override_self(&self) -> bool {
        self.is_set(AppSettings::AllArgsOverrideSelf)
    }

    /// Report whether [`Command::subcommand_precedence_over_arg`] is set
    pub fn is_subcommand_precedence_over_arg_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandPrecedenceOverArg)
    }

    /// Report whether [`Command::subcommand_negates_reqs`] is set
    pub fn is_subcommand_negates_reqs_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandsNegateReqs)
    }

    /// Report whether [`Command::multicall`] is set
    pub fn is_multicall_set(&self) -> bool {
        self.is_set(AppSettings::Multicall)
    }
}

// Internally used only
impl Command {
    pub(crate) fn get_override_usage(&self) -> Option<&StyledStr> {
        self.usage_str.as_ref()
    }

    pub(crate) fn get_override_help(&self) -> Option<&StyledStr> {
        self.help_str.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_help_template(&self) -> Option<&StyledStr> {
        self.template.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_term_width(&self) -> Option<usize> {
        self.term_w
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_max_term_width(&self) -> Option<usize> {
        self.max_w
    }

    pub(crate) fn get_replacement(&self, key: &str) -> Option<&[Str]> {
        self.replacers.get(key).map(|v| v.as_slice())
    }

    pub(crate) fn get_keymap(&self) -> &MKeyMap {
        &self.args
    }

    fn get_used_global_args(&self, matches: &ArgMatches, global_arg_vec: &mut Vec<Id>) {
        global_arg_vec.extend(
            self.args
                .args()
                .filter(|a| a.is_global_set())
                .map(|ga| ga.id.clone()),
        );
        if let Some((id, matches)) = matches.subcommand() {
            if let Some(used_sub) = self.find_subcommand(id) {
                used_sub.get_used_global_args(matches, global_arg_vec);
            }
        }
    }

    fn _do_parse(
        &mut self,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<ArgMatches> {
        debug!("Command::_do_parse");

        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing in case we run into a subcommand
        self._build_self(false);

        let mut matcher = ArgMatcher::new(self);

        // do the real parsing
        let mut parser = Parser::new(self);
        if let Err(error) = parser.get_matches_with(&mut matcher, raw_args, args_cursor) {
            if self.is_set(AppSettings::IgnoreErrors) {
                debug!("Command::_do_parse: ignoring error: {}", error);
            } else {
                return Err(error);
            }
        }

        let mut global_arg_vec = Default::default();
        self.get_used_global_args(&matcher, &mut global_arg_vec);

        matcher.propagate_globals(&global_arg_vec);

        Ok(matcher.into_inner())
    }

    /// Prepare for introspecting on all included [`Command`]s
    ///
    /// Call this on the top-level [`Command`] when done building and before reading state for
    /// cases like completions, custom help output, etc.
    pub fn build(&mut self) {
        self._build_recursive(true);
        self._build_bin_names_internal();
    }

    pub(crate) fn _build_recursive(&mut self, expand_help_tree: bool) {
        self._build_self(expand_help_tree);
        for subcmd in self.get_subcommands_mut() {
            subcmd._build_recursive(expand_help_tree);
        }
    }

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

    pub(crate) fn _build_subcommand(&mut self, name: &str) -> Option<&mut Self> {
        use std::fmt::Write;

        let mut mid_string = String::from(" ");
        #[cfg(feature = "usage")]
        if !self.is_subcommand_negates_reqs_set() && !self.is_args_conflicts_with_subcommands_set()
        {
            let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

            for s in &reqs {
                mid_string.push_str(&s.to_string());
                mid_string.push(' ');
            }
        }
        let is_multicall_set = self.is_multicall_set();

        let sc = some!(self.subcommands.iter_mut().find(|s| s.name == name));

        // Display subcommand name, short and long in usage
        let mut sc_names = String::new();
        sc_names.push_str(sc.name.as_str());
        let mut flag_subcmd = false;
        if let Some(l) = sc.get_long_flag() {
            write!(sc_names, "|--{}", l).unwrap();
            flag_subcmd = true;
        }
        if let Some(s) = sc.get_short_flag() {
            write!(sc_names, "|-{}", s).unwrap();
            flag_subcmd = true;
        }

        if flag_subcmd {
            sc_names = format!("{{{}}}", sc_names);
        }

        let usage_name = self
            .bin_name
            .as_ref()
            .map(|bin_name| format!("{}{}{}", bin_name, mid_string, sc_names))
            .unwrap_or(sc_names);
        sc.usage_name = Some(usage_name);

        // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
        // a space
        let bin_name = format!(
            "{}{}{}",
            self.bin_name.as_deref().unwrap_or_default(),
            if self.bin_name.is_some() { " " } else { "" },
            &*sc.name
        );
        debug!(
            "Command::_build_subcommand Setting bin_name of {} to {:?}",
            sc.name, bin_name
        );
        sc.bin_name = Some(bin_name);

        if sc.display_name.is_none() {
            let self_display_name = if is_multicall_set {
                self.display_name.as_deref().unwrap_or("")
            } else {
                self.display_name.as_deref().unwrap_or(&self.name)
            };
            let display_name = format!(
                "{}{}{}",
                self_display_name,
                if !self_display_name.is_empty() {
                    "-"
                } else {
                    ""
                },
                &*sc.name
            );
            debug!(
                "Command::_build_subcommand Setting display_name of {} to {:?}",
                sc.name, display_name
            );
            sc.display_name = Some(display_name);
        }

        // Ensure all args are built and ready to parse
        sc._build_self(false);

        Some(sc)
    }

    fn _build_bin_names_internal(&mut self) {
        debug!("Command::_build_bin_names");

        if !self.is_set(AppSettings::BinNameBuilt) {
            let mut mid_string = String::from(" ");
            #[cfg(feature = "usage")]
            if !self.is_subcommand_negates_reqs_set()
                && !self.is_args_conflicts_with_subcommands_set()
            {
                let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

                for s in &reqs {
                    mid_string.push_str(&s.to_string());
                    mid_string.push(' ');
                }
            }
            let is_multicall_set = self.is_multicall_set();

            let self_bin_name = if is_multicall_set {
                self.bin_name.as_deref().unwrap_or("")
            } else {
                self.bin_name.as_deref().unwrap_or(&self.name)
            }
            .to_owned();

            for mut sc in &mut self.subcommands {
                debug!("Command::_build_bin_names:iter: bin_name set...");

                if sc.usage_name.is_none() {
                    use std::fmt::Write;
                    // Display subcommand name, short and long in usage
                    let mut sc_names = String::new();
                    sc_names.push_str(sc.name.as_str());
                    let mut flag_subcmd = false;
                    if let Some(l) = sc.get_long_flag() {
                        write!(sc_names, "|--{}", l).unwrap();
                        flag_subcmd = true;
                    }
                    if let Some(s) = sc.get_short_flag() {
                        write!(sc_names, "|-{}", s).unwrap();
                        flag_subcmd = true;
                    }

                    if flag_subcmd {
                        sc_names = format!("{{{}}}", sc_names);
                    }

                    let usage_name = format!("{}{}{}", self_bin_name, mid_string, sc_names);
                    debug!(
                        "Command::_build_bin_names:iter: Setting usage_name of {} to {:?}",
                        sc.name, usage_name
                    );
                    sc.usage_name = Some(usage_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing usage_name of {} ({:?})",
                        sc.name, sc.usage_name
                    );
                }

                if sc.bin_name.is_none() {
                    let bin_name = format!(
                        "{}{}{}",
                        self_bin_name,
                        if !self_bin_name.is_empty() { " " } else { "" },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting bin_name of {} to {:?}",
                        sc.name, bin_name
                    );
                    sc.bin_name = Some(bin_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing bin_name of {} ({:?})",
                        sc.name, sc.bin_name
                    );
                }

                if sc.display_name.is_none() {
                    let self_display_name = if is_multicall_set {
                        self.display_name.as_deref().unwrap_or("")
                    } else {
                        self.display_name.as_deref().unwrap_or(&self.name)
                    };
                    let display_name = format!(
                        "{}{}{}",
                        self_display_name,
                        if !self_display_name.is_empty() {
                            "-"
                        } else {
                            ""
                        },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting display_name of {} to {:?}",
                        sc.name, display_name
                    );
                    sc.display_name = Some(display_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing display_name of {} ({:?})",
                        sc.name, sc.display_name
                    );
                }

                sc._build_bin_names_internal();
            }
            self.set(AppSettings::BinNameBuilt);
        } else {
            debug!("Command::_build_bin_names: already built");
        }
    }

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

    /// Propagate settings
    pub(crate) fn _propagate(&mut self) {
        debug!("Command::_propagate:{}", self.name);
        let mut subcommands = std::mem::take(&mut self.subcommands);
        for sc in &mut subcommands {
            self._propagate_subcommand(sc);
        }
        self.subcommands = subcommands;
    }

    fn _propagate_subcommand(&self, sc: &mut Self) {
        // We have to create a new scope in order to tell rustc the borrow of `sc` is
        // done and to recursively call this method
        {
            if self.settings.is_set(AppSettings::PropagateVersion) {
                if let Some(version) = self.version.as_ref() {
                    sc.version.get_or_insert_with(|| version.clone());
                }
                if let Some(long_version) = self.long_version.as_ref() {
                    sc.long_version.get_or_insert_with(|| long_version.clone());
                }
            }

            sc.settings = sc.settings | self.g_settings;
            sc.g_settings = sc.g_settings | self.g_settings;
            sc.term_w = self.term_w;
            sc.max_w = self.max_w;
        }
    }

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

    pub(crate) fn _render_version(&self, use_long: bool) -> String {
        debug!("Command::_render_version");

        let ver = if use_long {
            self.long_version
                .as_deref()
                .or(self.version.as_deref())
                .unwrap_or_default()
        } else {
            self.version
                .as_deref()
                .or(self.long_version.as_deref())
                .unwrap_or_default()
        };
        let display_name = self.get_display_name().unwrap_or_else(|| self.get_name());
        format!("{} {}\n", display_name, ver)
    }

    pub(crate) fn format_group(&self, g: &Id) -> StyledStr {
        let g_string = self
            .unroll_args_in_group(g)
            .iter()
            .filter_map(|x| self.find(x))
            .map(|x| {
                if x.is_positional() {
                    // Print val_name for positional arguments. e.g. <file_name>
                    x.name_no_brackets()
                } else {
                    // Print usage string for flags arguments, e.g. <--help>
                    x.to_string()
                }
            })
            .collect::<Vec<_>>()
            .join("|");
        let mut styled = StyledStr::new();
        styled.none("<");
        styled.none(g_string);
        styled.none(">");
        styled
    }
}

/// A workaround:
/// <https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999>
pub(crate) trait Captures<'a> {}
impl<'a, T> Captures<'a> for T {}

// Internal Query Methods
impl Command {
    /// Iterate through the *flags* & *options* arguments.
    #[cfg(any(feature = "usage", feature = "help"))]
    pub(crate) fn get_non_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| !a.is_positional())
    }

    pub(crate) fn find(&self, arg_id: &Id) -> Option<&Arg> {
        self.args.args().find(|a| a.get_id() == arg_id)
    }

    #[inline]
    pub(crate) fn contains_short(&self, s: char) -> bool {
        debug_assert!(
            self.is_set(AppSettings::Built),
            "If Command::_build hasn't been called, manually search through Arg shorts"
        );

        self.args.contains(s)
    }

    #[inline]
    pub(crate) fn set(&mut self, s: AppSettings) {
        self.settings.set(s)
    }

    #[inline]
    pub(crate) fn has_positionals(&self) -> bool {
        self.get_positionals().next().is_some()
    }

    #[cfg(any(feature = "usage", feature = "help"))]
    pub(crate) fn has_visible_subcommands(&self) -> bool {
        self.subcommands
            .iter()
            .any(|sc| sc.name != "help" && !sc.is_set(AppSettings::Hidden))
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this subcommand or is one of its aliases.
    #[inline]
    pub(crate) fn aliases_to(&self, name: impl AsRef<std::ffi::OsStr>) -> bool {
        let name = name.as_ref();
        self.get_name() == name || self.get_all_aliases().any(|alias| alias == name)
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this short flag subcommand or is one of its short flag aliases.
    #[inline]
    pub(crate) fn short_flag_aliases_to(&self, flag: char) -> bool {
        Some(flag) == self.short_flag
            || self.get_all_short_flag_aliases().any(|alias| flag == alias)
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this long flag subcommand or is one of its long flag aliases.
    #[inline]
    pub(crate) fn long_flag_aliases_to(&self, flag: &str) -> bool {
        match self.long_flag.as_ref() {
            Some(long_flag) => {
                long_flag == flag || self.get_all_long_flag_aliases().any(|alias| alias == flag)
            }
            None => self.get_all_long_flag_aliases().any(|alias| alias == flag),
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn id_exists(&self, id: &Id) -> bool {
        self.args.args().any(|x| x.get_id() == id) || self.groups.iter().any(|x| x.id == *id)
    }

    /// Iterate through the groups this arg is member of.
    pub(crate) fn groups_for_arg<'a>(&'a self, arg: &Id) -> impl Iterator<Item = Id> + 'a {
        debug!("Command::groups_for_arg: id={:?}", arg);
        let arg = arg.clone();
        self.groups
            .iter()
            .filter(move |grp| grp.args.iter().any(|a| a == &arg))
            .map(|grp| grp.id.clone())
    }

    pub(crate) fn find_group(&self, group_id: &Id) -> Option<&ArgGroup> {
        self.groups.iter().find(|g| g.id == *group_id)
    }

    /// Iterate through all the names of all subcommands (not recursively), including aliases.
    /// Used for suggestions.
    pub(crate) fn all_subcommand_names(&self) -> impl Iterator<Item = &str> + Captures {
        self.get_subcommands().flat_map(|sc| {
            let name = sc.get_name();
            let aliases = sc.get_all_aliases();
            std::iter::once(name).chain(aliases)
        })
    }

    pub(crate) fn required_graph(&self) -> ChildGraph<Id> {
        let mut reqs = ChildGraph::with_capacity(5);
        for a in self.args.args().filter(|a| a.is_required_set()) {
            reqs.insert(a.get_id().clone());
        }
        for group in &self.groups {
            if group.required {
                let idx = reqs.insert(group.id.clone());
                for a in &group.requires {
                    reqs.insert_child(idx, a.clone());
                }
            }
        }

        reqs
    }

    pub(crate) fn unroll_args_in_group(&self, group: &Id) -> Vec<Id> {
        debug!("Command::unroll_args_in_group: group={:?}", group);
        let mut g_vec = vec![group];
        let mut args = vec![];

        while let Some(g) = g_vec.pop() {
            for n in self
                .groups
                .iter()
                .find(|grp| grp.id == *g)
                .expect(INTERNAL_ERROR_MSG)
                .args
                .iter()
            {
                debug!("Command::unroll_args_in_group:iter: entity={:?}", n);
                if !args.contains(n) {
                    if self.find(n).is_some() {
                        debug!("Command::unroll_args_in_group:iter: this is an arg");
                        args.push(n.clone())
                    } else {
                        debug!("Command::unroll_args_in_group:iter: this is a group");
                        g_vec.push(n);
                    }
                }
            }
        }

        args
    }

    pub(crate) fn unroll_arg_requires<F>(&self, func: F, arg: &Id) -> Vec<Id>
    where
        F: Fn(&(ArgPredicate, Id)) -> Option<Id>,
    {
        let mut processed = vec![];
        let mut r_vec = vec![arg];
        let mut args = vec![];

        while let Some(a) = r_vec.pop() {
            if processed.contains(&a) {
                continue;
            }

            processed.push(a);

            if let Some(arg) = self.find(a) {
                for r in arg.requires.iter().filter_map(&func) {
                    if let Some(req) = self.find(&r) {
                        if !req.requires.is_empty() {
                            r_vec.push(req.get_id())
                        }
                    }
                    args.push(r);
                }
            }
        }

        args
    }

src/builder/arg.rs (line 4130)

    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

    /// Write the values such as <name1> <name2>
    fn render_arg_val(&self, required: bool) -> String {
        let mut rendered = String::new();

        let num_vals = self.get_num_args().unwrap_or_else(|| 1.into());

        let mut val_names = if self.val_names.is_empty() {
            vec![self.id.as_internal_str().to_owned()]
        } else {
            self.val_names.clone()
        };
        if val_names.len() == 1 {
            let min = num_vals.min_values().max(1);
            let val_name = val_names.pop().unwrap();
            val_names = vec![val_name; min];
        }

        debug_assert!(self.is_takes_value_set());
        for (n, val_name) in val_names.iter().enumerate() {
            let arg_name = if self.is_positional() && (num_vals.min_values() == 0 || !required) {
                format!("[{}]", val_name)
            } else {
                format!("<{}>", val_name)
            };

            if n != 0 {
                rendered.push(' ');
            }
            rendered.push_str(&arg_name);
        }

        let mut extra_values = false;
        extra_values |= val_names.len() < num_vals.max_values();
        if self.is_positional() && matches!(*self.get_action(), ArgAction::Append) {
            extra_values = true;
        }
        if extra_values {
            rendered.push_str("...");
        }

        rendered
    }

    /// Either multiple values or occurrences
    pub(crate) fn is_multiple(&self) -> bool {
        self.is_multiple_values_set() || matches!(*self.get_action(), ArgAction::Append)
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_display_order(&self) -> usize {
        self.disp_ord.unwrap_or(999)
    }
}

impl From<&'_ Arg> for Arg {
    fn from(a: &Arg) -> Self {
        a.clone()
    }
}

impl PartialEq for Arg {
    fn eq(&self, other: &Arg) -> bool {
        self.get_id() == other.get_id()
    }
}

impl PartialOrd for Arg {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for Arg {
    fn cmp(&self, other: &Arg) -> Ordering {
        self.get_id().cmp(other.get_id())
    }

src/output/help_template.rs (line 976)

fn option_sort_key(arg: &Arg) -> (usize, String) {
    // Formatting key like this to ensure that:
    // 1. Argument has long flags are printed just after short flags.
    // 2. For two args both have short flags like `-c` and `-C`, the
    //    `-C` arg is printed just after the `-c` arg
    // 3. For args without short or long flag, print them at last(sorted
    //    by arg name).
    // Example order: -a, -b, -B, -s, --select-file, --select-folder, -x

    let key = if let Some(x) = arg.get_short() {
        let mut s = x.to_ascii_lowercase().to_string();
        s.push(if x.is_ascii_lowercase() { '0' } else { '1' });
        s
    } else if let Some(x) = arg.get_long() {
        x.to_string()
    } else {
        let mut s = '{'.to_string();
        s.push_str(arg.get_id().as_str());
        s
    };
    (arg.get_display_order(), key)
}

src/output/usage.rs (line 173)

    fn needs_options_tag(&self) -> bool {
        debug!("Usage::needs_options_tag");
        'outer: for f in self.cmd.get_non_positionals() {
            debug!("Usage::needs_options_tag:iter: f={}", f.get_id());

            // Don't print `[OPTIONS]` just for help or version
            if f.get_long() == Some("help") || f.get_long() == Some("version") {
                debug!("Usage::needs_options_tag:iter Option is built-in");
                continue;
            }

            if f.is_hide_set() {
                debug!("Usage::needs_options_tag:iter Option is hidden");
                continue;
            }
            if f.is_required_set() {
                debug!("Usage::needs_options_tag:iter Option is required");
                continue;
            }
            for grp_s in self.cmd.groups_for_arg(f.get_id()) {
                debug!("Usage::needs_options_tag:iter:iter: grp_s={:?}", grp_s);
                if self.cmd.get_groups().any(|g| g.id == grp_s && g.required) {
                    debug!("Usage::needs_options_tag:iter:iter: Group is required");
                    continue 'outer;
                }
            }

            debug!("Usage::needs_options_tag:iter: [OPTIONS] required");
            return true;
        }

        debug!("Usage::needs_options_tag: [OPTIONS] not required");
        false
    }

    // Returns the required args in usage string form by fully unrolling all groups
    pub(crate) fn write_args(&self, incls: &[Id], force_optional: bool, styled: &mut StyledStr) {
        for required in self.get_args(incls, force_optional) {
            styled.none(" ");
            styled.extend(required.into_iter());
        }
    }

    pub(crate) fn get_args(&self, incls: &[Id], force_optional: bool) -> Vec<StyledStr> {
        debug!("Usage::get_args: incls={:?}", incls,);

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => false,
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!("Usage::get_args: unrolled_reqs={:?}", unrolled_reqs);

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let stylized = arg.stylized(Some(!force_optional));
                if let Some(index) = arg.get_index() {
                    let new_len = index + 1;
                    if required_positionals.len() < new_len {
                        required_positionals.resize(new_len, None);
                    }
                    required_positionals[index] = Some(stylized);
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        for pos in self.cmd.get_positionals() {
            if pos.is_hide_set() {
                continue;
            }
            if required_groups_members.contains(pos.get_id()) {
                continue;
            }

            let index = pos.get_index().unwrap();
            let new_len = index + 1;
            if required_positionals.len() < new_len {
                required_positionals.resize(new_len, None);
            }
            if required_positionals[index].is_some() {
                if pos.is_last_set() {
                    let styled = required_positionals[index].take().unwrap();
                    let mut new = StyledStr::new();
                    new.literal("-- ");
                    new.extend(styled.into_iter());
                    required_positionals[index] = Some(new);
                }
            } else {
                let mut styled;
                if pos.is_last_set() {
                    styled = StyledStr::new();
                    styled.literal("[-- ");
                    styled.extend(pos.stylized(Some(true)).into_iter());
                    styled.literal("]");
                } else {
                    styled = pos.stylized(Some(false));
                }
                required_positionals[index] = Some(styled);
            }
            if pos.is_last_set() && force_optional {
                required_positionals[index] = None;
            }
        }

        let mut ret_val = Vec::new();
        if !force_optional {
            ret_val.extend(required_opts);
            ret_val.extend(required_groups);
        }
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_args: ret_val={:?}", ret_val);
        ret_val
    }

    pub(crate) fn get_required_usage_from(
        &self,
        incls: &[Id],
        matcher: Option<&ArgMatcher>,
        incl_last: bool,
    ) -> Vec<StyledStr> {
        debug!(
            "Usage::get_required_usage_from: incls={:?}, matcher={:?}, incl_last={:?}",
            incls,
            matcher.is_some(),
            incl_last
        );

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => {
                        if let Some(matcher) = matcher {
                            matcher.check_explicit(a, val)
                        } else {
                            false
                        }
                    }
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!(
            "Usage::get_required_usage_from: unrolled_reqs={:?}",
            unrolled_reqs
        );

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let is_present = matcher
                    .map(|m| {
                        group_members
                            .iter()
                            .any(|arg| m.check_explicit(arg, &ArgPredicate::IsPresent))
                    })
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} group is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let is_present = matcher
                    .map(|m| m.check_explicit(req, &ArgPredicate::IsPresent))
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} arg is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let stylized = arg.stylized(Some(true));
                if let Some(index) = arg.get_index() {
                    if !arg.is_last_set() || incl_last {
                        let new_len = index + 1;
                        if required_positionals.len() < new_len {
                            required_positionals.resize(new_len, None);
                        }
                        required_positionals[index] = Some(stylized);
                    }
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        let mut ret_val = Vec::new();
        ret_val.extend(required_opts);
        ret_val.extend(required_groups);
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_required_usage_from: ret_val={:?}", ret_val);
        ret_val
    }

src/parser/validator.rs (line 37)

    pub(crate) fn validate(
        &mut self,
        parse_state: ParseState,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<()> {
        debug!("Validator::validate");
        let mut conflicts = Conflicts::new();
        let has_subcmd = matcher.subcommand_name().is_some();

        if let ParseState::Opt(a) = parse_state {
            debug!("Validator::validate: needs_val_of={:?}", a);

            let o = &self.cmd[&a];
            let should_err = if let Some(v) = matcher.args.get(o.get_id()) {
                v.all_val_groups_empty() && o.get_min_vals() != 0
            } else {
                true
            };
            if should_err {
                return Err(Error::empty_value(
                    self.cmd,
                    &get_possible_values_cli(o)
                        .iter()
                        .filter(|pv| !pv.is_hide_set())
                        .map(|n| n.get_name().to_owned())
                        .collect::<Vec<_>>(),
                    o.to_string(),
                ));
            }
        }

        if !has_subcmd && self.cmd.is_arg_required_else_help_set() {
            let num_user_values = matcher
                .arg_ids()
                .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
                .count();
            if num_user_values == 0 {
                let message = self.cmd.write_help_err(false);
                return Err(Error::display_help_error(self.cmd, message));
            }
        }
        if !has_subcmd && self.cmd.is_subcommand_required_set() {
            let bn = self
                .cmd
                .get_bin_name()
                .unwrap_or_else(|| self.cmd.get_name());
            return Err(Error::missing_subcommand(
                self.cmd,
                bn.to_string(),
                self.cmd
                    .all_subcommand_names()
                    .map(|s| s.to_owned())
                    .collect::<Vec<_>>(),
                Usage::new(self.cmd)
                    .required(&self.required)
                    .create_usage_with_title(&[]),
            ));
        }

        ok!(self.validate_conflicts(matcher, &mut conflicts));
        if !(self.cmd.is_subcommand_negates_reqs_set() && has_subcmd) {
            ok!(self.validate_required(matcher, &mut conflicts));
        }

        Ok(())
    }

    fn validate_conflicts(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_conflicts");

        ok!(self.validate_exclusive(matcher));

        for arg_id in matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .filter(|arg_id| self.cmd.find(arg_id).is_some())
        {
            debug!("Validator::validate_conflicts::iter: id={:?}", arg_id);
            let conflicts = conflicts.gather_conflicts(self.cmd, matcher, arg_id);
            ok!(self.build_conflict_err(arg_id, &conflicts, matcher));
        }

        Ok(())
    }

    fn validate_exclusive(&self, matcher: &ArgMatcher) -> ClapResult<()> {
        debug!("Validator::validate_exclusive");
        let args_count = matcher
            .arg_ids()
            .filter(|arg_id| {
                matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    // Avoid including our own groups by checking none of them.  If a group is present, the
                    // args for the group will be.
                    && self.cmd.find(arg_id).is_some()
            })
            .count();
        if args_count <= 1 {
            // Nothing present to conflict with
            return Ok(());
        }

        matcher
            .arg_ids()
            .filter(|arg_id| {
                matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
            })
            .filter_map(|name| {
                debug!("Validator::validate_exclusive:iter:{:?}", name);
                self.cmd
                    .find(name)
                    // Find `arg`s which are exclusive but also appear with other args.
                    .filter(|&arg| arg.is_exclusive_set() && args_count > 1)
            })
            // Throw an error for the first conflict found.
            .try_for_each(|arg| {
                Err(Error::argument_conflict(
                    self.cmd,
                    arg.to_string(),
                    Vec::new(),
                    Usage::new(self.cmd)
                        .required(&self.required)
                        .create_usage_with_title(&[]),
                ))
            })
    }

    fn build_conflict_err(
        &self,
        name: &Id,
        conflict_ids: &[Id],
        matcher: &ArgMatcher,
    ) -> ClapResult<()> {
        if conflict_ids.is_empty() {
            return Ok(());
        }

        debug!("Validator::build_conflict_err: name={:?}", name);
        let mut seen = FlatSet::new();
        let conflicts = conflict_ids
            .iter()
            .flat_map(|c_id| {
                if self.cmd.find_group(c_id).is_some() {
                    self.cmd.unroll_args_in_group(c_id)
                } else {
                    vec![c_id.clone()]
                }
            })
            .filter_map(|c_id| {
                seen.insert(c_id.clone()).then(|| {
                    let c_arg = self.cmd.find(&c_id).expect(INTERNAL_ERROR_MSG);
                    c_arg.to_string()
                })
            })
            .collect();

        let former_arg = self.cmd.find(name).expect(INTERNAL_ERROR_MSG);
        let usg = self.build_conflict_err_usage(matcher, conflict_ids);
        Err(Error::argument_conflict(
            self.cmd,
            former_arg.to_string(),
            conflicts,
            usg,
        ))
    }

    fn build_conflict_err_usage(
        &self,
        matcher: &ArgMatcher,
        conflicting_keys: &[Id],
    ) -> Option<StyledStr> {
        let used_filtered: Vec<Id> = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .filter(|n| {
                // Filter out the args we don't want to specify.
                self.cmd.find(n).map_or(false, |a| !a.is_hide_set())
            })
            .filter(|key| !conflicting_keys.contains(key))
            .cloned()
            .collect();
        let required: Vec<Id> = used_filtered
            .iter()
            .filter_map(|key| self.cmd.find(key))
            .flat_map(|arg| arg.requires.iter().map(|item| &item.1))
            .filter(|key| !used_filtered.contains(key) && !conflicting_keys.contains(key))
            .chain(used_filtered.iter())
            .cloned()
            .collect();
        Usage::new(self.cmd)
            .required(&self.required)
            .create_usage_with_title(&required)
    }

    fn gather_requires(&mut self, matcher: &ArgMatcher) {
        debug!("Validator::gather_requires");
        for name in matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
        {
            debug!("Validator::gather_requires:iter:{:?}", name);
            if let Some(arg) = self.cmd.find(name) {
                let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                    let required = matcher.check_explicit(arg.get_id(), val);
                    required.then(|| req_arg.clone())
                };

                for req in self.cmd.unroll_arg_requires(is_relevant, arg.get_id()) {
                    self.required.insert(req);
                }
            } else if let Some(g) = self.cmd.find_group(name) {
                debug!("Validator::gather_requires:iter:{:?}:group", name);
                for r in &g.requires {
                    self.required.insert(r.clone());
                }
            }
        }
    }

    fn validate_required(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_required: required={:?}", self.required);
        self.gather_requires(matcher);

        let mut missing_required = Vec::new();
        let mut highest_index = 0;

        let is_exclusive_present = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .any(|id| {
                self.cmd
                    .find(id)
                    .map(|arg| arg.is_exclusive_set())
                    .unwrap_or_default()
            });
        debug!(
            "Validator::validate_required: is_exclusive_present={}",
            is_exclusive_present
        );

        for arg_or_group in self
            .required
            .iter()
            .filter(|r| !matcher.check_explicit(r, &ArgPredicate::IsPresent))
        {
            debug!("Validator::validate_required:iter:aog={:?}", arg_or_group);
            if let Some(arg) = self.cmd.find(arg_or_group) {
                debug!("Validator::validate_required:iter: This is an arg");
                if !is_exclusive_present && !self.is_missing_required_ok(arg, matcher, conflicts) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        arg.get_id()
                    );
                    missing_required.push(arg.get_id().clone());
                    if !arg.is_last_set() {
                        highest_index = highest_index.max(arg.get_index().unwrap_or(0));
                    }
                }
            } else if let Some(group) = self.cmd.find_group(arg_or_group) {
                debug!("Validator::validate_required:iter: This is a group");
                if !self
                    .cmd
                    .unroll_args_in_group(&group.id)
                    .iter()
                    .any(|a| matcher.check_explicit(a, &ArgPredicate::IsPresent))
                {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        group.get_id()
                    );
                    missing_required.push(group.get_id().clone());
                }
            }
        }

        // Validate the conditionally required args
        for a in self
            .cmd
            .get_arguments()
            .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
        {
            let mut required = false;

            for (other, val) in &a.r_ifs {
                if matcher.check_explicit(other, &ArgPredicate::Equals(val.into())) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        a.get_id()
                    );
                    required = true;
                }
            }

            let match_all = a.r_ifs_all.iter().all(|(other, val)| {
                matcher.check_explicit(other, &ArgPredicate::Equals(val.into()))
            });
            if match_all && !a.r_ifs_all.is_empty() {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if (!a.r_unless.is_empty() || !a.r_unless_all.is_empty())
                && self.fails_arg_required_unless(a, matcher)
            {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if required {
                missing_required.push(a.get_id().clone());
                if !a.is_last_set() {
                    highest_index = highest_index.max(a.get_index().unwrap_or(0));
                }
            }
        }

        // For display purposes, include all of the preceding positional arguments
        if !self.cmd.is_allow_missing_positional_set() {
            for pos in self
                .cmd
                .get_positionals()
                .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
            {
                if pos.get_index() < Some(highest_index) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        pos.get_id()
                    );
                    missing_required.push(pos.get_id().clone());
                }
            }
        }

        if !missing_required.is_empty() {
            ok!(self.missing_required_error(matcher, missing_required));
        }

        Ok(())
    }

    fn is_missing_required_ok(
        &self,
        a: &Arg,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> bool {
        debug!("Validator::is_missing_required_ok: {}", a.get_id());
        let conflicts = conflicts.gather_conflicts(self.cmd, matcher, a.get_id());
        !conflicts.is_empty()
    }

Additional examples can be found in:

• src/builder/debug_asserts.rs
• src/parser/parser.rs

pub fn get_help(&self) -> Option<&StyledStr>

Get the help specified for this argument, if any

Examples found in repository

src/output/help_template.rs (line 471)

    fn write_arg(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        let spec_vals = &self.spec_vals(arg);

        self.none(TAB);
        self.short(arg);
        self.long(arg);
        self.writer.extend(arg.stylize_arg_suffix(None).into_iter());
        self.align_to_about(arg, next_line_help, longest);

        let about = if self.use_long {
            arg.get_long_help()
                .or_else(|| arg.get_help())
                .unwrap_or_default()
        } else {
            arg.get_help()
                .or_else(|| arg.get_long_help())
                .unwrap_or_default()
        };

        self.help(Some(arg), about, spec_vals, next_line_help, longest);
    }

    /// Writes argument's short command to the wrapped stream.
    fn short(&mut self, arg: &Arg) {
        debug!("HelpTemplate::short");

        if let Some(s) = arg.get_short() {
            self.literal(format!("-{}", s));
        } else if arg.get_long().is_some() {
            self.none("    ");
        }
    }

    /// Writes argument's long command to the wrapped stream.
    fn long(&mut self, arg: &Arg) {
        debug!("HelpTemplate::long");
        if let Some(long) = arg.get_long() {
            if arg.get_short().is_some() {
                self.none(", ");
            }
            self.literal(format!("--{}", long));
        }
    }

    /// Write alignment padding between arg's switches/values and its about message.
    fn align_to_about(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        debug!(
            "HelpTemplate::align_to_about: arg={}, next_line_help={}, longest={}",
            arg.get_id(),
            next_line_help,
            longest
        );
        if self.use_long || next_line_help {
            // long help prints messages on the next line so it doesn't need to align text
            debug!("HelpTemplate::align_to_about: printing long help so skip alignment");
        } else if !arg.is_positional() {
            let self_len = display_width(&arg.to_string());
            // Since we're writing spaces from the tab point we first need to know if we
            // had a long and short, or just short
            let padding = if arg.get_long().is_some() {
                // Only account 4 after the val
                TAB_WIDTH
            } else {
                // Only account for ', --' + 4 after the val
                TAB_WIDTH + 4
            };
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=false arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        } else {
            let self_len = display_width(&arg.to_string());
            let padding = TAB_WIDTH;
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=true arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        }
    }

    /// Writes argument's help to the wrapped stream.
    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

src/builder/command.rs (line 4132)

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

pub fn get_long_help(&self) -> Option<&StyledStr>

Get the long help specified for this argument, if any

Examples

let arg = Arg::new("foo").long_help("long help");
assert_eq!(Some("long help".to_owned()), arg.get_long_help().map(|s| s.to_string()));

Examples found in repository

src/output/help_template.rs (line 470)

    fn write_arg(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        let spec_vals = &self.spec_vals(arg);

        self.none(TAB);
        self.short(arg);
        self.long(arg);
        self.writer.extend(arg.stylize_arg_suffix(None).into_iter());
        self.align_to_about(arg, next_line_help, longest);

        let about = if self.use_long {
            arg.get_long_help()
                .or_else(|| arg.get_help())
                .unwrap_or_default()
        } else {
            arg.get_help()
                .or_else(|| arg.get_long_help())
                .unwrap_or_default()
        };

        self.help(Some(arg), about, spec_vals, next_line_help, longest);
    }

src/builder/command.rs (line 4132)

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

    /// Propagate settings
    pub(crate) fn _propagate(&mut self) {
        debug!("Command::_propagate:{}", self.name);
        let mut subcommands = std::mem::take(&mut self.subcommands);
        for sc in &mut subcommands {
            self._propagate_subcommand(sc);
        }
        self.subcommands = subcommands;
    }

    fn _propagate_subcommand(&self, sc: &mut Self) {
        // We have to create a new scope in order to tell rustc the borrow of `sc` is
        // done and to recursively call this method
        {
            if self.settings.is_set(AppSettings::PropagateVersion) {
                if let Some(version) = self.version.as_ref() {
                    sc.version.get_or_insert_with(|| version.clone());
                }
                if let Some(long_version) = self.long_version.as_ref() {
                    sc.long_version.get_or_insert_with(|| long_version.clone());
                }
            }

            sc.settings = sc.settings | self.g_settings;
            sc.g_settings = sc.g_settings | self.g_settings;
            sc.term_w = self.term_w;
            sc.max_w = self.max_w;
        }
    }

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

    pub(crate) fn _render_version(&self, use_long: bool) -> String {
        debug!("Command::_render_version");

        let ver = if use_long {
            self.long_version
                .as_deref()
                .or(self.version.as_deref())
                .unwrap_or_default()
        } else {
            self.version
                .as_deref()
                .or(self.long_version.as_deref())
                .unwrap_or_default()
        };
        let display_name = self.get_display_name().unwrap_or_else(|| self.get_name());
        format!("{} {}\n", display_name, ver)
    }

    pub(crate) fn format_group(&self, g: &Id) -> StyledStr {
        let g_string = self
            .unroll_args_in_group(g)
            .iter()
            .filter_map(|x| self.find(x))
            .map(|x| {
                if x.is_positional() {
                    // Print val_name for positional arguments. e.g. <file_name>
                    x.name_no_brackets()
                } else {
                    // Print usage string for flags arguments, e.g. <--help>
                    x.to_string()
                }
            })
            .collect::<Vec<_>>()
            .join("|");
        let mut styled = StyledStr::new();
        styled.none("<");
        styled.none(g_string);
        styled.none(">");
        styled
    }
}

/// A workaround:
/// <https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999>
pub(crate) trait Captures<'a> {}
impl<'a, T> Captures<'a> for T {}

// Internal Query Methods
impl Command {
    /// Iterate through the *flags* & *options* arguments.
    #[cfg(any(feature = "usage", feature = "help"))]
    pub(crate) fn get_non_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| !a.is_positional())
    }

    pub(crate) fn find(&self, arg_id: &Id) -> Option<&Arg> {
        self.args.args().find(|a| a.get_id() == arg_id)
    }

    #[inline]
    pub(crate) fn contains_short(&self, s: char) -> bool {
        debug_assert!(
            self.is_set(AppSettings::Built),
            "If Command::_build hasn't been called, manually search through Arg shorts"
        );

        self.args.contains(s)
    }

    #[inline]
    pub(crate) fn set(&mut self, s: AppSettings) {
        self.settings.set(s)
    }

    #[inline]
    pub(crate) fn has_positionals(&self) -> bool {
        self.get_positionals().next().is_some()
    }

    #[cfg(any(feature = "usage", feature = "help"))]
    pub(crate) fn has_visible_subcommands(&self) -> bool {
        self.subcommands
            .iter()
            .any(|sc| sc.name != "help" && !sc.is_set(AppSettings::Hidden))
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this subcommand or is one of its aliases.
    #[inline]
    pub(crate) fn aliases_to(&self, name: impl AsRef<std::ffi::OsStr>) -> bool {
        let name = name.as_ref();
        self.get_name() == name || self.get_all_aliases().any(|alias| alias == name)
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this short flag subcommand or is one of its short flag aliases.
    #[inline]
    pub(crate) fn short_flag_aliases_to(&self, flag: char) -> bool {
        Some(flag) == self.short_flag
            || self.get_all_short_flag_aliases().any(|alias| flag == alias)
    }

    /// Check if this subcommand can be referred to as `name`. In other words,
    /// check if `name` is the name of this long flag subcommand or is one of its long flag aliases.
    #[inline]
    pub(crate) fn long_flag_aliases_to(&self, flag: &str) -> bool {
        match self.long_flag.as_ref() {
            Some(long_flag) => {
                long_flag == flag || self.get_all_long_flag_aliases().any(|alias| alias == flag)
            }
            None => self.get_all_long_flag_aliases().any(|alias| alias == flag),
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn id_exists(&self, id: &Id) -> bool {
        self.args.args().any(|x| x.get_id() == id) || self.groups.iter().any(|x| x.id == *id)
    }

    /// Iterate through the groups this arg is member of.
    pub(crate) fn groups_for_arg<'a>(&'a self, arg: &Id) -> impl Iterator<Item = Id> + 'a {
        debug!("Command::groups_for_arg: id={:?}", arg);
        let arg = arg.clone();
        self.groups
            .iter()
            .filter(move |grp| grp.args.iter().any(|a| a == &arg))
            .map(|grp| grp.id.clone())
    }

    pub(crate) fn find_group(&self, group_id: &Id) -> Option<&ArgGroup> {
        self.groups.iter().find(|g| g.id == *group_id)
    }

    /// Iterate through all the names of all subcommands (not recursively), including aliases.
    /// Used for suggestions.
    pub(crate) fn all_subcommand_names(&self) -> impl Iterator<Item = &str> + Captures {
        self.get_subcommands().flat_map(|sc| {
            let name = sc.get_name();
            let aliases = sc.get_all_aliases();
            std::iter::once(name).chain(aliases)
        })
    }

    pub(crate) fn required_graph(&self) -> ChildGraph<Id> {
        let mut reqs = ChildGraph::with_capacity(5);
        for a in self.args.args().filter(|a| a.is_required_set()) {
            reqs.insert(a.get_id().clone());
        }
        for group in &self.groups {
            if group.required {
                let idx = reqs.insert(group.id.clone());
                for a in &group.requires {
                    reqs.insert_child(idx, a.clone());
                }
            }
        }

        reqs
    }

    pub(crate) fn unroll_args_in_group(&self, group: &Id) -> Vec<Id> {
        debug!("Command::unroll_args_in_group: group={:?}", group);
        let mut g_vec = vec![group];
        let mut args = vec![];

        while let Some(g) = g_vec.pop() {
            for n in self
                .groups
                .iter()
                .find(|grp| grp.id == *g)
                .expect(INTERNAL_ERROR_MSG)
                .args
                .iter()
            {
                debug!("Command::unroll_args_in_group:iter: entity={:?}", n);
                if !args.contains(n) {
                    if self.find(n).is_some() {
                        debug!("Command::unroll_args_in_group:iter: this is an arg");
                        args.push(n.clone())
                    } else {
                        debug!("Command::unroll_args_in_group:iter: this is a group");
                        g_vec.push(n);
                    }
                }
            }
        }

        args
    }

    pub(crate) fn unroll_arg_requires<F>(&self, func: F, arg: &Id) -> Vec<Id>
    where
        F: Fn(&(ArgPredicate, Id)) -> Option<Id>,
    {
        let mut processed = vec![];
        let mut r_vec = vec![arg];
        let mut args = vec![];

        while let Some(a) = r_vec.pop() {
            if processed.contains(&a) {
                continue;
            }

            processed.push(a);

            if let Some(arg) = self.find(a) {
                for r in arg.requires.iter().filter_map(&func) {
                    if let Some(req) = self.find(&r) {
                        if !req.requires.is_empty() {
                            r_vec.push(req.get_id())
                        }
                    }
                    args.push(r);
                }
            }
        }

        args
    }

    /// Find a flag subcommand name by short flag or an alias
    pub(crate) fn find_short_subcmd(&self, c: char) -> Option<&str> {
        self.get_subcommands()
            .find(|sc| sc.short_flag_aliases_to(c))
            .map(|sc| sc.get_name())
    }

    /// Find a flag subcommand name by long flag or an alias
    pub(crate) fn find_long_subcmd(&self, long: &str) -> Option<&str> {
        self.get_subcommands()
            .find(|sc| sc.long_flag_aliases_to(long))
            .map(|sc| sc.get_name())
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_display_order(&self) -> usize {
        self.disp_ord.unwrap_or(999)
    }

    pub(crate) fn write_help_err(&self, mut use_long: bool) -> StyledStr {
        debug!(
            "Command::write_help_err: {}, use_long={:?}",
            self.get_display_name().unwrap_or_else(|| self.get_name()),
            use_long && self.long_help_exists(),
        );

        use_long = use_long && self.long_help_exists();
        let usage = Usage::new(self);

        let mut styled = StyledStr::new();
        write_help(&mut styled, self, &usage, use_long);

        styled
    }

    pub(crate) fn write_version_err(&self, use_long: bool) -> StyledStr {
        let msg = self._render_version(use_long);
        let mut styled = StyledStr::new();
        styled.none(msg);
        styled
    }

    pub(crate) fn long_help_exists(&self) -> bool {
        debug!("Command::long_help_exists: {}", self.long_help_exists);
        self.long_help_exists
    }

    fn long_help_exists_(&self) -> bool {
        debug!("Command::long_help_exists");
        // In this case, both must be checked. This allows the retention of
        // original formatting, but also ensures that the actual -h or --help
        // specified by the user is sent through. If hide_short_help is not included,
        // then items specified with hidden_short_help will also be hidden.
        let should_long = |v: &Arg| {
            v.get_long_help().is_some()
                || v.is_hide_long_help_set()
                || v.is_hide_short_help_set()
                || v.get_possible_values()
                    .iter()
                    .any(PossibleValue::should_show_help)
        };

        // Subcommands aren't checked because we prefer short help for them, deferring to
        // `cmd subcmd --help` for more.
        self.get_long_about().is_some()
            || self.get_before_long_help().is_some()
            || self.get_after_long_help().is_some()
            || self.get_arguments().any(should_long)
    }

pub fn get_help_heading(&self) -> Option<&str>

Get the help heading specified for this argument, if any

Examples found in repository

src/output/help_template.rs (line 340)

    pub(crate) fn write_all_args(&mut self) {
        debug!("HelpTemplate::write_all_args");
        let pos = self
            .cmd
            .get_positionals()
            .filter(|a| a.get_help_heading().is_none())
            .filter(|arg| should_show_arg(self.use_long, arg))
            .collect::<Vec<_>>();
        let non_pos = self
            .cmd
            .get_non_positionals()
            .filter(|a| a.get_help_heading().is_none())
            .filter(|arg| should_show_arg(self.use_long, arg))
            .collect::<Vec<_>>();
        let subcmds = self.cmd.has_visible_subcommands();

        let custom_headings = self
            .cmd
            .get_arguments()
            .filter_map(|arg| arg.get_help_heading())
            .collect::<FlatSet<_>>();

        let mut first = true;

        if subcmds {
            if !first {
                self.none("\n\n");
            }
            first = false;
            let default_help_heading = Str::from("Commands");
            self.header(
                self.cmd
                    .get_subcommand_help_heading()
                    .unwrap_or(&default_help_heading),
            );
            self.header(":\n");

            self.write_subcommands(self.cmd);
        }

        if !pos.is_empty() {
            if !first {
                self.none("\n\n");
            }
            first = false;
            // Write positional args if any
            self.header("Arguments:\n");
            self.write_args(&pos, "Arguments", positional_sort_key);
        }

        if !non_pos.is_empty() {
            if !first {
                self.none("\n\n");
            }
            first = false;
            self.header("Options:\n");
            self.write_args(&non_pos, "Options", option_sort_key);
        }
        if !custom_headings.is_empty() {
            for heading in custom_headings {
                let args = self
                    .cmd
                    .get_arguments()
                    .filter(|a| {
                        if let Some(help_heading) = a.get_help_heading() {
                            return help_heading == heading;
                        }
                        false
                    })
                    .filter(|arg| should_show_arg(self.use_long, arg))
                    .collect::<Vec<_>>();

                if !args.is_empty() {
                    if !first {
                        self.none("\n\n");
                    }
                    first = false;
                    self.header(format!("{}:\n", heading));
                    self.write_args(&args, heading, option_sort_key);
                }
            }
        }
    }

pub fn get_short(&self) -> Option<char>

Get the short option name for this argument, if any

Examples found in repository

src/builder/arg.rs (line 3924)

    pub fn is_positional(&self) -> bool {
        self.get_long().is_none() && self.get_short().is_none()
    }

    /// Reports whether [`Arg::required`] is set
    pub fn is_required_set(&self) -> bool {
        self.is_set(ArgSettings::Required)
    }

    pub(crate) fn is_multiple_values_set(&self) -> bool {
        self.get_num_args().unwrap_or_default().is_multiple()
    }

    pub(crate) fn is_takes_value_set(&self) -> bool {
        self.get_action().takes_values()
    }

    /// Report whether [`Arg::allow_hyphen_values`] is set
    pub fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(ArgSettings::AllowHyphenValues)
    }

    /// Report whether [`Arg::allow_negative_numbers`] is set
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(ArgSettings::AllowNegativeNumbers)
    }

    /// Behavior when parsing the argument
    pub fn get_action(&self) -> &super::ArgAction {
        const DEFAULT: super::ArgAction = super::ArgAction::Set;
        self.action.as_ref().unwrap_or(&DEFAULT)
    }

    /// Configured parser for argument values
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .arg(
    ///         clap::Arg::new("port")
    ///             .value_parser(clap::value_parser!(usize))
    ///     );
    /// let value_parser = cmd.get_arguments()
    ///     .find(|a| a.get_id() == "port").unwrap()
    ///     .get_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_value_parser(&self) -> &super::ValueParser {
        if let Some(value_parser) = self.value_parser.as_ref() {
            value_parser
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::string();
            &DEFAULT
        }
    }

    /// Report whether [`Arg::global`] is set
    pub fn is_global_set(&self) -> bool {
        self.is_set(ArgSettings::Global)
    }

    /// Report whether [`Arg::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(ArgSettings::NextLineHelp)
    }

    /// Report whether [`Arg::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(ArgSettings::Hidden)
    }

    /// Report whether [`Arg::hide_default_value`] is set
    pub fn is_hide_default_value_set(&self) -> bool {
        self.is_set(ArgSettings::HideDefaultValue)
    }

    /// Report whether [`Arg::hide_possible_values`] is set
    pub fn is_hide_possible_values_set(&self) -> bool {
        self.is_set(ArgSettings::HidePossibleValues)
    }

    /// Report whether [`Arg::hide_env`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnv)
    }

    /// Report whether [`Arg::hide_env_values`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_values_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnvValues)
    }

    /// Report whether [`Arg::hide_short_help`] is set
    pub fn is_hide_short_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenShortHelp)
    }

    /// Report whether [`Arg::hide_long_help`] is set
    pub fn is_hide_long_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenLongHelp)
    }

    /// Report whether [`Arg::require_equals`] is set
    pub fn is_require_equals_set(&self) -> bool {
        self.is_set(ArgSettings::RequireEquals)
    }

    /// Reports whether [`Arg::exclusive`] is set
    pub fn is_exclusive_set(&self) -> bool {
        self.is_set(ArgSettings::Exclusive)
    }

    /// Report whether [`Arg::trailing_var_arg`] is set
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(ArgSettings::TrailingVarArg)
    }

    /// Reports whether [`Arg::last`] is set
    pub fn is_last_set(&self) -> bool {
        self.is_set(ArgSettings::Last)
    }

    /// Reports whether [`Arg::ignore_case`] is set
    pub fn is_ignore_case_set(&self) -> bool {
        self.is_set(ArgSettings::IgnoreCase)
    }
}

/// # Internally used only
impl Arg {
    pub(crate) fn _build(&mut self) {
        if self.action.is_none() {
            if self.num_vals == Some(ValueRange::EMPTY) {
                let action = super::ArgAction::SetTrue;
                self.action = Some(action);
            } else {
                let action =
                    if self.is_positional() && self.num_vals.unwrap_or_default().is_unbounded() {
                        // Allow collecting arguments interleaved with flags
                        //
                        // Bounded values are probably a group and the user should explicitly opt-in to
                        // Append
                        super::ArgAction::Append
                    } else {
                        super::ArgAction::Set
                    };
                self.action = Some(action);
            }
        }
        if let Some(action) = self.action.as_ref() {
            if let Some(default_value) = action.default_value() {
                if self.default_vals.is_empty() {
                    self.default_vals = vec![default_value.into()];
                }
            }
            if let Some(default_value) = action.default_missing_value() {
                if self.default_missing_vals.is_empty() {
                    self.default_missing_vals = vec![default_value.into()];
                }
            }
        }

        if self.value_parser.is_none() {
            if let Some(default) = self.action.as_ref().and_then(|a| a.default_value_parser()) {
                self.value_parser = Some(default);
            } else {
                self.value_parser = Some(super::ValueParser::string());
            }
        }

        let val_names_len = self.val_names.len();
        if val_names_len > 1 {
            self.num_vals.get_or_insert(val_names_len.into());
        } else {
            let nargs = if self.get_action().takes_values() {
                ValueRange::SINGLE
            } else {
                ValueRange::EMPTY
            };
            self.num_vals.get_or_insert(nargs);
        }
    }

    // Used for positionals when printing
    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

src/output/help_template.rs (line 486)

    fn short(&mut self, arg: &Arg) {
        debug!("HelpTemplate::short");

        if let Some(s) = arg.get_short() {
            self.literal(format!("-{}", s));
        } else if arg.get_long().is_some() {
            self.none("    ");
        }
    }

    /// Writes argument's long command to the wrapped stream.
    fn long(&mut self, arg: &Arg) {
        debug!("HelpTemplate::long");
        if let Some(long) = arg.get_long() {
            if arg.get_short().is_some() {
                self.none(", ");
            }
            self.literal(format!("--{}", long));
        }
    }

    /// Write alignment padding between arg's switches/values and its about message.
    fn align_to_about(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        debug!(
            "HelpTemplate::align_to_about: arg={}, next_line_help={}, longest={}",
            arg.get_id(),
            next_line_help,
            longest
        );
        if self.use_long || next_line_help {
            // long help prints messages on the next line so it doesn't need to align text
            debug!("HelpTemplate::align_to_about: printing long help so skip alignment");
        } else if !arg.is_positional() {
            let self_len = display_width(&arg.to_string());
            // Since we're writing spaces from the tab point we first need to know if we
            // had a long and short, or just short
            let padding = if arg.get_long().is_some() {
                // Only account 4 after the val
                TAB_WIDTH
            } else {
                // Only account for ', --' + 4 after the val
                TAB_WIDTH + 4
            };
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=false arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        } else {
            let self_len = display_width(&arg.to_string());
            let padding = TAB_WIDTH;
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=true arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        }
    }

    /// Writes argument's help to the wrapped stream.
    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

    fn header<T: Into<String>>(&mut self, msg: T) {
        self.writer.header(msg);
    }

    fn literal<T: Into<String>>(&mut self, msg: T) {
        self.writer.literal(msg);
    }

    fn none<T: Into<String>>(&mut self, msg: T) {
        self.writer.none(msg);
    }

    fn get_spaces(&self, n: usize) -> String {
        " ".repeat(n)
    }

    fn spaces(&mut self, n: usize) {
        self.none(self.get_spaces(n));
    }
}

/// Subcommand handling
impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
    /// Writes help for subcommands of a Parser Object to the wrapped stream.
    fn write_subcommands(&mut self, cmd: &Command) {
        debug!("HelpTemplate::write_subcommands");
        // The shortest an arg can legally be is 2 (i.e. '-x')
        let mut longest = 2;
        let mut ord_v = Vec::new();
        for subcommand in cmd
            .get_subcommands()
            .filter(|subcommand| should_show_subcommand(subcommand))
        {
            let mut styled = StyledStr::new();
            styled.literal(subcommand.get_name());
            if let Some(short) = subcommand.get_short_flag() {
                styled.none(", ");
                styled.literal(format!("-{}", short));
            }
            if let Some(long) = subcommand.get_long_flag() {
                styled.none(", ");
                styled.literal(format!("--{}", long));
            }
            longest = longest.max(styled.display_width());
            ord_v.push((subcommand.get_display_order(), styled, subcommand));
        }
        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));

        debug!("HelpTemplate::write_subcommands longest = {}", longest);

        let next_line_help = self.will_subcommands_wrap(cmd.get_subcommands(), longest);

        let mut first = true;
        for (_, sc_str, sc) in ord_v {
            if first {
                first = false;
            } else {
                self.none("\n");
            }
            self.write_subcommand(sc_str, sc, next_line_help, longest);
        }
    }

    /// Will use next line help on writing subcommands.
    fn will_subcommands_wrap<'a>(
        &self,
        subcommands: impl IntoIterator<Item = &'a Command>,
        longest: usize,
    ) -> bool {
        subcommands
            .into_iter()
            .filter(|&subcommand| should_show_subcommand(subcommand))
            .any(|subcommand| {
                let spec_vals = &self.sc_spec_vals(subcommand);
                self.subcommand_next_line_help(subcommand, spec_vals, longest)
            })
    }

    fn write_subcommand(
        &mut self,
        sc_str: StyledStr,
        cmd: &Command,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::write_subcommand");

        let spec_vals = &self.sc_spec_vals(cmd);

        let about = cmd
            .get_about()
            .or_else(|| cmd.get_long_about())
            .unwrap_or_default();

        self.subcmd(sc_str, next_line_help, longest);
        self.help(None, about, spec_vals, next_line_help, longest)
    }

    fn sc_spec_vals(&self, a: &Command) -> String {
        debug!("HelpTemplate::sc_spec_vals: a={}", a.get_name());
        let mut spec_vals = vec![];

        let mut short_als = a
            .get_visible_short_flag_aliases()
            .map(|a| format!("-{}", a))
            .collect::<Vec<_>>();
        let als = a.get_visible_aliases().map(|s| s.to_string());
        short_als.extend(als);
        let all_als = short_als.join(", ");
        if !all_als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found aliases...{:?}",
                a.get_all_aliases().collect::<Vec<_>>()
            );
            debug!(
                "HelpTemplate::spec_vals: Found short flag aliases...{:?}",
                a.get_all_short_flag_aliases().collect::<Vec<_>>()
            );
            spec_vals.push(format!("[aliases: {}]", all_als));
        }

        spec_vals.join(" ")
    }

    fn subcommand_next_line_help(&self, cmd: &Command, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help | self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = cmd.get_about().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = longest + TAB_WIDTH * 2;
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    /// Writes subcommand to the wrapped stream.
    fn subcmd(&mut self, sc_str: StyledStr, next_line_help: bool, longest: usize) {
        let width = sc_str.display_width();

        self.none(TAB);
        self.writer.extend(sc_str.into_iter());
        if !next_line_help {
            self.spaces(longest + TAB_WIDTH - width);
        }
    }
}

const NEXT_LINE_INDENT: &str = "        ";

type ArgSortKey = fn(arg: &Arg) -> (usize, String);

fn positional_sort_key(arg: &Arg) -> (usize, String) {
    (arg.get_index().unwrap_or(0), String::new())
}

fn option_sort_key(arg: &Arg) -> (usize, String) {
    // Formatting key like this to ensure that:
    // 1. Argument has long flags are printed just after short flags.
    // 2. For two args both have short flags like `-c` and `-C`, the
    //    `-C` arg is printed just after the `-c` arg
    // 3. For args without short or long flag, print them at last(sorted
    //    by arg name).
    // Example order: -a, -b, -B, -s, --select-file, --select-folder, -x

    let key = if let Some(x) = arg.get_short() {
        let mut s = x.to_ascii_lowercase().to_string();
        s.push(if x.is_ascii_lowercase() { '0' } else { '1' });
        s
    } else if let Some(x) = arg.get_long() {
        x.to_string()
    } else {
        let mut s = '{'.to_string();
        s.push_str(arg.get_id().as_str());
        s
    };
    (arg.get_display_order(), key)
}

pub(crate) fn dimensions() -> (Option<usize>, Option<usize>) {
    #[cfg(not(feature = "wrap_help"))]
    return (None, None);

    #[cfg(feature = "wrap_help")]
    terminal_size::terminal_size()
        .map(|(w, h)| (Some(w.0.into()), Some(h.0.into())))
        .unwrap_or_else(|| (parse_env("COLUMNS"), parse_env("LINES")))
}

#[cfg(feature = "wrap_help")]
fn parse_env(var: &str) -> Option<usize> {
    some!(some!(std::env::var_os(var)).to_str())
        .parse::<usize>()
        .ok()
}

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

fn should_show_subcommand(subcommand: &Command) -> bool {
    !subcommand.is_hide_set()
}

fn replace_newline_var(styled: &mut StyledStr) {
    for (_, content) in styled.iter_mut() {
        *content = content.replace("{n}", "\n");
    }
}

fn longest_filter(arg: &Arg) -> bool {
    arg.is_takes_value_set() || arg.get_long().is_some() || arg.get_short().is_none()
}

src/builder/debug_asserts.rs (line 70)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

pub fn get_visible_short_aliases(&self) -> Option<Vec<char>>

Get visible short aliases for this argument, if any

Examples found in repository

src/builder/arg.rs (line 3771)

    pub fn get_short_and_visible_aliases(&self) -> Option<Vec<char>> {
        let mut shorts = match self.short {
            Some(short) => vec![short],
            None => return None,
        };
        if let Some(aliases) = self.get_visible_short_aliases() {
            shorts.extend(aliases);
        }
        Some(shorts)
    }

pub fn get_all_short_aliases(&self) -> Option<Vec<char>>

Get all short aliases for this argument, if any, both visible and hidden.

pub fn get_short_and_visible_aliases(&self) -> Option<Vec<char>>

Get the short option name and its visible aliases, if any

pub fn get_long(&self) -> Option<&str>

Get the long option name for this argument, if any

Examples found in repository

src/output/help_template.rs (line 488)

    fn short(&mut self, arg: &Arg) {
        debug!("HelpTemplate::short");

        if let Some(s) = arg.get_short() {
            self.literal(format!("-{}", s));
        } else if arg.get_long().is_some() {
            self.none("    ");
        }
    }

    /// Writes argument's long command to the wrapped stream.
    fn long(&mut self, arg: &Arg) {
        debug!("HelpTemplate::long");
        if let Some(long) = arg.get_long() {
            if arg.get_short().is_some() {
                self.none(", ");
            }
            self.literal(format!("--{}", long));
        }
    }

    /// Write alignment padding between arg's switches/values and its about message.
    fn align_to_about(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        debug!(
            "HelpTemplate::align_to_about: arg={}, next_line_help={}, longest={}",
            arg.get_id(),
            next_line_help,
            longest
        );
        if self.use_long || next_line_help {
            // long help prints messages on the next line so it doesn't need to align text
            debug!("HelpTemplate::align_to_about: printing long help so skip alignment");
        } else if !arg.is_positional() {
            let self_len = display_width(&arg.to_string());
            // Since we're writing spaces from the tab point we first need to know if we
            // had a long and short, or just short
            let padding = if arg.get_long().is_some() {
                // Only account 4 after the val
                TAB_WIDTH
            } else {
                // Only account for ', --' + 4 after the val
                TAB_WIDTH + 4
            };
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=false arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        } else {
            let self_len = display_width(&arg.to_string());
            let padding = TAB_WIDTH;
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=true arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        }
    }

    /// Writes argument's help to the wrapped stream.
    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

    fn header<T: Into<String>>(&mut self, msg: T) {
        self.writer.header(msg);
    }

    fn literal<T: Into<String>>(&mut self, msg: T) {
        self.writer.literal(msg);
    }

    fn none<T: Into<String>>(&mut self, msg: T) {
        self.writer.none(msg);
    }

    fn get_spaces(&self, n: usize) -> String {
        " ".repeat(n)
    }

    fn spaces(&mut self, n: usize) {
        self.none(self.get_spaces(n));
    }
}

/// Subcommand handling
impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
    /// Writes help for subcommands of a Parser Object to the wrapped stream.
    fn write_subcommands(&mut self, cmd: &Command) {
        debug!("HelpTemplate::write_subcommands");
        // The shortest an arg can legally be is 2 (i.e. '-x')
        let mut longest = 2;
        let mut ord_v = Vec::new();
        for subcommand in cmd
            .get_subcommands()
            .filter(|subcommand| should_show_subcommand(subcommand))
        {
            let mut styled = StyledStr::new();
            styled.literal(subcommand.get_name());
            if let Some(short) = subcommand.get_short_flag() {
                styled.none(", ");
                styled.literal(format!("-{}", short));
            }
            if let Some(long) = subcommand.get_long_flag() {
                styled.none(", ");
                styled.literal(format!("--{}", long));
            }
            longest = longest.max(styled.display_width());
            ord_v.push((subcommand.get_display_order(), styled, subcommand));
        }
        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));

        debug!("HelpTemplate::write_subcommands longest = {}", longest);

        let next_line_help = self.will_subcommands_wrap(cmd.get_subcommands(), longest);

        let mut first = true;
        for (_, sc_str, sc) in ord_v {
            if first {
                first = false;
            } else {
                self.none("\n");
            }
            self.write_subcommand(sc_str, sc, next_line_help, longest);
        }
    }

    /// Will use next line help on writing subcommands.
    fn will_subcommands_wrap<'a>(
        &self,
        subcommands: impl IntoIterator<Item = &'a Command>,
        longest: usize,
    ) -> bool {
        subcommands
            .into_iter()
            .filter(|&subcommand| should_show_subcommand(subcommand))
            .any(|subcommand| {
                let spec_vals = &self.sc_spec_vals(subcommand);
                self.subcommand_next_line_help(subcommand, spec_vals, longest)
            })
    }

    fn write_subcommand(
        &mut self,
        sc_str: StyledStr,
        cmd: &Command,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::write_subcommand");

        let spec_vals = &self.sc_spec_vals(cmd);

        let about = cmd
            .get_about()
            .or_else(|| cmd.get_long_about())
            .unwrap_or_default();

        self.subcmd(sc_str, next_line_help, longest);
        self.help(None, about, spec_vals, next_line_help, longest)
    }

    fn sc_spec_vals(&self, a: &Command) -> String {
        debug!("HelpTemplate::sc_spec_vals: a={}", a.get_name());
        let mut spec_vals = vec![];

        let mut short_als = a
            .get_visible_short_flag_aliases()
            .map(|a| format!("-{}", a))
            .collect::<Vec<_>>();
        let als = a.get_visible_aliases().map(|s| s.to_string());
        short_als.extend(als);
        let all_als = short_als.join(", ");
        if !all_als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found aliases...{:?}",
                a.get_all_aliases().collect::<Vec<_>>()
            );
            debug!(
                "HelpTemplate::spec_vals: Found short flag aliases...{:?}",
                a.get_all_short_flag_aliases().collect::<Vec<_>>()
            );
            spec_vals.push(format!("[aliases: {}]", all_als));
        }

        spec_vals.join(" ")
    }

    fn subcommand_next_line_help(&self, cmd: &Command, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help | self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = cmd.get_about().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = longest + TAB_WIDTH * 2;
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    /// Writes subcommand to the wrapped stream.
    fn subcmd(&mut self, sc_str: StyledStr, next_line_help: bool, longest: usize) {
        let width = sc_str.display_width();

        self.none(TAB);
        self.writer.extend(sc_str.into_iter());
        if !next_line_help {
            self.spaces(longest + TAB_WIDTH - width);
        }
    }
}

const NEXT_LINE_INDENT: &str = "        ";

type ArgSortKey = fn(arg: &Arg) -> (usize, String);

fn positional_sort_key(arg: &Arg) -> (usize, String) {
    (arg.get_index().unwrap_or(0), String::new())
}

fn option_sort_key(arg: &Arg) -> (usize, String) {
    // Formatting key like this to ensure that:
    // 1. Argument has long flags are printed just after short flags.
    // 2. For two args both have short flags like `-c` and `-C`, the
    //    `-C` arg is printed just after the `-c` arg
    // 3. For args without short or long flag, print them at last(sorted
    //    by arg name).
    // Example order: -a, -b, -B, -s, --select-file, --select-folder, -x

    let key = if let Some(x) = arg.get_short() {
        let mut s = x.to_ascii_lowercase().to_string();
        s.push(if x.is_ascii_lowercase() { '0' } else { '1' });
        s
    } else if let Some(x) = arg.get_long() {
        x.to_string()
    } else {
        let mut s = '{'.to_string();
        s.push_str(arg.get_id().as_str());
        s
    };
    (arg.get_display_order(), key)
}

pub(crate) fn dimensions() -> (Option<usize>, Option<usize>) {
    #[cfg(not(feature = "wrap_help"))]
    return (None, None);

    #[cfg(feature = "wrap_help")]
    terminal_size::terminal_size()
        .map(|(w, h)| (Some(w.0.into()), Some(h.0.into())))
        .unwrap_or_else(|| (parse_env("COLUMNS"), parse_env("LINES")))
}

#[cfg(feature = "wrap_help")]
fn parse_env(var: &str) -> Option<usize> {
    some!(some!(std::env::var_os(var)).to_str())
        .parse::<usize>()
        .ok()
}

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

fn should_show_subcommand(subcommand: &Command) -> bool {
    !subcommand.is_hide_set()
}

fn replace_newline_var(styled: &mut StyledStr) {
    for (_, content) in styled.iter_mut() {
        *content = content.replace("{n}", "\n");
    }
}

fn longest_filter(arg: &Arg) -> bool {
    arg.is_takes_value_set() || arg.get_long().is_some() || arg.get_short().is_none()
}

src/builder/arg.rs (line 3811)

    pub fn get_long_and_visible_aliases(&self) -> Option<Vec<&str>> {
        let mut longs = match self.get_long() {
            Some(long) => vec![long],
            None => return None,
        };
        if let Some(aliases) = self.get_visible_aliases() {
            longs.extend(aliases);
        }
        Some(longs)
    }

    /// Get the names of possible values for this argument. Only useful for user
    /// facing applications, such as building help messages or man files
    pub fn get_possible_values(&self) -> Vec<PossibleValue> {
        if !self.is_takes_value_set() {
            vec![]
        } else {
            self.get_value_parser()
                .possible_values()
                .map(|pvs| pvs.collect())
                .unwrap_or_default()
        }
    }

    /// Get the names of values for this argument.
    #[inline]
    pub fn get_value_names(&self) -> Option<&[Str]> {
        if self.val_names.is_empty() {
            None
        } else {
            Some(&self.val_names)
        }
    }

    /// Get the number of values for this argument.
    #[inline]
    pub fn get_num_args(&self) -> Option<ValueRange> {
        self.num_vals
    }

    #[inline]
    pub(crate) fn get_min_vals(&self) -> usize {
        self.get_num_args().expect(INTERNAL_ERROR_MSG).min_values()
    }

    /// Get the delimiter between multiple values
    #[inline]
    pub fn get_value_delimiter(&self) -> Option<char> {
        self.val_delim
    }

    /// Get the index of this argument, if any
    #[inline]
    pub fn get_index(&self) -> Option<usize> {
        self.index
    }

    /// Get the value hint of this argument
    pub fn get_value_hint(&self) -> ValueHint {
        self.value_hint.unwrap_or_else(|| {
            if self.is_takes_value_set() {
                let type_id = self.get_value_parser().type_id();
                if type_id == crate::parser::AnyValueId::of::<std::path::PathBuf>() {
                    ValueHint::AnyPath
                } else {
                    ValueHint::default()
                }
            } else {
                ValueHint::default()
            }
        })
    }

    /// Get the environment variable name specified for this argument, if any
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use std::ffi::OsStr;
    /// # use clap::Arg;
    /// let arg = Arg::new("foo").env("ENVIRONMENT");
    /// assert_eq!(arg.get_env(), Some(OsStr::new("ENVIRONMENT")));
    /// ```
    #[cfg(feature = "env")]
    pub fn get_env(&self) -> Option<&std::ffi::OsStr> {
        self.env.as_ref().map(|x| x.0.as_os_str())
    }

    /// Get the default values specified for this argument, if any
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Arg;
    /// let arg = Arg::new("foo").default_value("default value");
    /// assert_eq!(arg.get_default_values(), &["default value"]);
    /// ```
    pub fn get_default_values(&self) -> &[OsStr] {
        &self.default_vals
    }

    /// Checks whether this argument is a positional or not.
    ///
    /// # Examples
    ///
    /// ```
    /// # use clap::Arg;
    /// let arg = Arg::new("foo");
    /// assert_eq!(arg.is_positional(), true);
    ///
    /// let arg = Arg::new("foo").long("foo");
    /// assert_eq!(arg.is_positional(), false);
    /// ```
    pub fn is_positional(&self) -> bool {
        self.get_long().is_none() && self.get_short().is_none()
    }

    /// Reports whether [`Arg::required`] is set
    pub fn is_required_set(&self) -> bool {
        self.is_set(ArgSettings::Required)
    }

    pub(crate) fn is_multiple_values_set(&self) -> bool {
        self.get_num_args().unwrap_or_default().is_multiple()
    }

    pub(crate) fn is_takes_value_set(&self) -> bool {
        self.get_action().takes_values()
    }

    /// Report whether [`Arg::allow_hyphen_values`] is set
    pub fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(ArgSettings::AllowHyphenValues)
    }

    /// Report whether [`Arg::allow_negative_numbers`] is set
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(ArgSettings::AllowNegativeNumbers)
    }

    /// Behavior when parsing the argument
    pub fn get_action(&self) -> &super::ArgAction {
        const DEFAULT: super::ArgAction = super::ArgAction::Set;
        self.action.as_ref().unwrap_or(&DEFAULT)
    }

    /// Configured parser for argument values
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .arg(
    ///         clap::Arg::new("port")
    ///             .value_parser(clap::value_parser!(usize))
    ///     );
    /// let value_parser = cmd.get_arguments()
    ///     .find(|a| a.get_id() == "port").unwrap()
    ///     .get_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_value_parser(&self) -> &super::ValueParser {
        if let Some(value_parser) = self.value_parser.as_ref() {
            value_parser
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::string();
            &DEFAULT
        }
    }

    /// Report whether [`Arg::global`] is set
    pub fn is_global_set(&self) -> bool {
        self.is_set(ArgSettings::Global)
    }

    /// Report whether [`Arg::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(ArgSettings::NextLineHelp)
    }

    /// Report whether [`Arg::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(ArgSettings::Hidden)
    }

    /// Report whether [`Arg::hide_default_value`] is set
    pub fn is_hide_default_value_set(&self) -> bool {
        self.is_set(ArgSettings::HideDefaultValue)
    }

    /// Report whether [`Arg::hide_possible_values`] is set
    pub fn is_hide_possible_values_set(&self) -> bool {
        self.is_set(ArgSettings::HidePossibleValues)
    }

    /// Report whether [`Arg::hide_env`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnv)
    }

    /// Report whether [`Arg::hide_env_values`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_values_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnvValues)
    }

    /// Report whether [`Arg::hide_short_help`] is set
    pub fn is_hide_short_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenShortHelp)
    }

    /// Report whether [`Arg::hide_long_help`] is set
    pub fn is_hide_long_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenLongHelp)
    }

    /// Report whether [`Arg::require_equals`] is set
    pub fn is_require_equals_set(&self) -> bool {
        self.is_set(ArgSettings::RequireEquals)
    }

    /// Reports whether [`Arg::exclusive`] is set
    pub fn is_exclusive_set(&self) -> bool {
        self.is_set(ArgSettings::Exclusive)
    }

    /// Report whether [`Arg::trailing_var_arg`] is set
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(ArgSettings::TrailingVarArg)
    }

    /// Reports whether [`Arg::last`] is set
    pub fn is_last_set(&self) -> bool {
        self.is_set(ArgSettings::Last)
    }

    /// Reports whether [`Arg::ignore_case`] is set
    pub fn is_ignore_case_set(&self) -> bool {
        self.is_set(ArgSettings::IgnoreCase)
    }
}

/// # Internally used only
impl Arg {
    pub(crate) fn _build(&mut self) {
        if self.action.is_none() {
            if self.num_vals == Some(ValueRange::EMPTY) {
                let action = super::ArgAction::SetTrue;
                self.action = Some(action);
            } else {
                let action =
                    if self.is_positional() && self.num_vals.unwrap_or_default().is_unbounded() {
                        // Allow collecting arguments interleaved with flags
                        //
                        // Bounded values are probably a group and the user should explicitly opt-in to
                        // Append
                        super::ArgAction::Append
                    } else {
                        super::ArgAction::Set
                    };
                self.action = Some(action);
            }
        }
        if let Some(action) = self.action.as_ref() {
            if let Some(default_value) = action.default_value() {
                if self.default_vals.is_empty() {
                    self.default_vals = vec![default_value.into()];
                }
            }
            if let Some(default_value) = action.default_missing_value() {
                if self.default_missing_vals.is_empty() {
                    self.default_missing_vals = vec![default_value.into()];
                }
            }
        }

        if self.value_parser.is_none() {
            if let Some(default) = self.action.as_ref().and_then(|a| a.default_value_parser()) {
                self.value_parser = Some(default);
            } else {
                self.value_parser = Some(super::ValueParser::string());
            }
        }

        let val_names_len = self.val_names.len();
        if val_names_len > 1 {
            self.num_vals.get_or_insert(val_names_len.into());
        } else {
            let nargs = if self.get_action().takes_values() {
                ValueRange::SINGLE
            } else {
                ValueRange::EMPTY
            };
            self.num_vals.get_or_insert(nargs);
        }
    }

    // Used for positionals when printing
    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

src/output/usage.rs (line 160)

    fn needs_options_tag(&self) -> bool {
        debug!("Usage::needs_options_tag");
        'outer: for f in self.cmd.get_non_positionals() {
            debug!("Usage::needs_options_tag:iter: f={}", f.get_id());

            // Don't print `[OPTIONS]` just for help or version
            if f.get_long() == Some("help") || f.get_long() == Some("version") {
                debug!("Usage::needs_options_tag:iter Option is built-in");
                continue;
            }

            if f.is_hide_set() {
                debug!("Usage::needs_options_tag:iter Option is hidden");
                continue;
            }
            if f.is_required_set() {
                debug!("Usage::needs_options_tag:iter Option is required");
                continue;
            }
            for grp_s in self.cmd.groups_for_arg(f.get_id()) {
                debug!("Usage::needs_options_tag:iter:iter: grp_s={:?}", grp_s);
                if self.cmd.get_groups().any(|g| g.id == grp_s && g.required) {
                    debug!("Usage::needs_options_tag:iter:iter: Group is required");
                    continue 'outer;
                }
            }

            debug!("Usage::needs_options_tag:iter: [OPTIONS] required");
            return true;
        }

        debug!("Usage::needs_options_tag: [OPTIONS] not required");
        false
    }

src/parser/parser.rs (line 762)

    fn parse_long_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        long_arg: Result<&str, &RawOsStr>,
        long_value: Option<&RawOsStr>,
        parse_state: &ParseState,
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        // maybe here lifetime should be 'a
        debug!("Parser::parse_long_arg");

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
            self.cmd[opt].is_allow_hyphen_values_set())
        {
            debug!("Parser::parse_long_arg: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        }

        debug!("Parser::parse_long_arg: Does it contain '='...");
        let long_arg = match long_arg {
            Ok(long_arg) => long_arg,
            Err(long_arg) => {
                return Ok(ParseResult::NoMatchingArg {
                    arg: long_arg.to_str_lossy().into_owned(),
                });
            }
        };
        if long_arg.is_empty() {
            debug_assert!(
                long_value.is_some(),
                "`--` should be filtered out before this point"
            );
        }

        let arg = if let Some(arg) = self.cmd.get_keymap().get(long_arg) {
            debug!("Parser::parse_long_arg: Found valid arg or flag '{}'", arg);
            Some((long_arg, arg))
        } else if self.cmd.is_infer_long_args_set() {
            self.cmd.get_arguments().find_map(|a| {
                if let Some(long) = a.get_long() {
                    if long.starts_with(long_arg) {
                        return Some((long, a));
                    }
                }
                a.aliases
                    .iter()
                    .find_map(|(alias, _)| alias.starts_with(long_arg).then(|| (alias.as_str(), a)))
            })
        } else {
            None
        };

        if let Some((_long_arg, arg)) = arg {
            let ident = Identifier::Long;
            *valid_arg_found = true;
            if arg.is_takes_value_set() {
                debug!(
                    "Parser::parse_long_arg({:?}): Found an arg with value '{:?}'",
                    long_arg, &long_value
                );
                let has_eq = long_value.is_some();
                self.parse_opt_value(ident, long_value, arg, matcher, has_eq)
            } else if let Some(rest) = long_value {
                let required = self.cmd.required_graph();
                debug!(
                    "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                    long_arg, rest
                );
                let mut used: Vec<Id> = matcher
                    .arg_ids()
                    .filter(|arg_id| {
                        matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    })
                    .filter(|&n| {
                        self.cmd.find(n).map_or(true, |a| {
                            !(a.is_hide_set() || required.contains(a.get_id()))
                        })
                    })
                    .cloned()
                    .collect();
                used.push(arg.get_id().clone());

                Ok(ParseResult::UnneededAttachedValue {
                    rest: rest.to_str_lossy().into_owned(),
                    used,
                    arg: arg.to_string(),
                })
            } else {
                debug!("Parser::parse_long_arg({:?}): Presence validated", long_arg);
                let trailing_idx = None;
                self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    vec![],
                    trailing_idx,
                    matcher,
                )
            }
        } else if let Some(sc_name) = self.possible_long_flag_subcommand(long_arg) {
            Ok(ParseResult::FlagSubCommand(sc_name.to_string()))
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
        {
            debug!(
                "Parser::parse_long_args: positional at {} allows hyphens",
                pos_counter
            );
            Ok(ParseResult::MaybeHyphenValue)
        } else {
            Ok(ParseResult::NoMatchingArg {
                arg: long_arg.to_owned(),
            })
        }
    }

src/builder/debug_asserts.rs (line 81)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

pub fn get_visible_aliases(&self) -> Option<Vec<&str>>

Get visible aliases for this argument, if any

Examples found in repository

src/builder/arg.rs (line 3815)

    pub fn get_long_and_visible_aliases(&self) -> Option<Vec<&str>> {
        let mut longs = match self.get_long() {
            Some(long) => vec![long],
            None => return None,
        };
        if let Some(aliases) = self.get_visible_aliases() {
            longs.extend(aliases);
        }
        Some(longs)
    }

pub fn get_all_aliases(&self) -> Option<Vec<&str>>

Get all aliases for this argument, if any, both visible and hidden.

pub fn get_long_and_visible_aliases(&self) -> Option<Vec<&str>>

Get the long option name and its visible aliases, if any

pub fn get_possible_values(&self) -> Vec<PossibleValue>

Get the names of possible values for this argument. Only useful for user facing applications, such as building help messages or man files

Examples found in repository

src/builder/command.rs (line 4599)

    fn long_help_exists_(&self) -> bool {
        debug!("Command::long_help_exists");
        // In this case, both must be checked. This allows the retention of
        // original formatting, but also ensures that the actual -h or --help
        // specified by the user is sent through. If hide_short_help is not included,
        // then items specified with hidden_short_help will also be hidden.
        let should_long = |v: &Arg| {
            v.get_long_help().is_some()
                || v.is_hide_long_help_set()
                || v.is_hide_short_help_set()
                || v.get_possible_values()
                    .iter()
                    .any(PossibleValue::should_show_help)
        };

        // Subcommands aren't checked because we prefer short help for them, deferring to
        // `cmd subcmd --help` for more.
        self.get_long_about().is_some()
            || self.get_before_long_help().is_some()
            || self.get_after_long_help().is_some()
            || self.get_arguments().any(should_long)
    }

src/output/help_template.rs (line 602)

    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

pub fn get_value_names(&self) -> Option<&[Str]>

Get the names of values for this argument.

Examples found in repository

src/builder/debug_asserts.rs (line 758)

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn get_num_args(&self) -> Option<ValueRange>

Get the number of values for this argument.

Examples found in repository

src/builder/arg.rs (line 3852)

    pub(crate) fn get_min_vals(&self) -> usize {
        self.get_num_args().expect(INTERNAL_ERROR_MSG).min_values()
    }

    /// Get the delimiter between multiple values
    #[inline]
    pub fn get_value_delimiter(&self) -> Option<char> {
        self.val_delim
    }

    /// Get the index of this argument, if any
    #[inline]
    pub fn get_index(&self) -> Option<usize> {
        self.index
    }

    /// Get the value hint of this argument
    pub fn get_value_hint(&self) -> ValueHint {
        self.value_hint.unwrap_or_else(|| {
            if self.is_takes_value_set() {
                let type_id = self.get_value_parser().type_id();
                if type_id == crate::parser::AnyValueId::of::<std::path::PathBuf>() {
                    ValueHint::AnyPath
                } else {
                    ValueHint::default()
                }
            } else {
                ValueHint::default()
            }
        })
    }

    /// Get the environment variable name specified for this argument, if any
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use std::ffi::OsStr;
    /// # use clap::Arg;
    /// let arg = Arg::new("foo").env("ENVIRONMENT");
    /// assert_eq!(arg.get_env(), Some(OsStr::new("ENVIRONMENT")));
    /// ```
    #[cfg(feature = "env")]
    pub fn get_env(&self) -> Option<&std::ffi::OsStr> {
        self.env.as_ref().map(|x| x.0.as_os_str())
    }

    /// Get the default values specified for this argument, if any
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Arg;
    /// let arg = Arg::new("foo").default_value("default value");
    /// assert_eq!(arg.get_default_values(), &["default value"]);
    /// ```
    pub fn get_default_values(&self) -> &[OsStr] {
        &self.default_vals
    }

    /// Checks whether this argument is a positional or not.
    ///
    /// # Examples
    ///
    /// ```
    /// # use clap::Arg;
    /// let arg = Arg::new("foo");
    /// assert_eq!(arg.is_positional(), true);
    ///
    /// let arg = Arg::new("foo").long("foo");
    /// assert_eq!(arg.is_positional(), false);
    /// ```
    pub fn is_positional(&self) -> bool {
        self.get_long().is_none() && self.get_short().is_none()
    }

    /// Reports whether [`Arg::required`] is set
    pub fn is_required_set(&self) -> bool {
        self.is_set(ArgSettings::Required)
    }

    pub(crate) fn is_multiple_values_set(&self) -> bool {
        self.get_num_args().unwrap_or_default().is_multiple()
    }

    pub(crate) fn is_takes_value_set(&self) -> bool {
        self.get_action().takes_values()
    }

    /// Report whether [`Arg::allow_hyphen_values`] is set
    pub fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(ArgSettings::AllowHyphenValues)
    }

    /// Report whether [`Arg::allow_negative_numbers`] is set
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(ArgSettings::AllowNegativeNumbers)
    }

    /// Behavior when parsing the argument
    pub fn get_action(&self) -> &super::ArgAction {
        const DEFAULT: super::ArgAction = super::ArgAction::Set;
        self.action.as_ref().unwrap_or(&DEFAULT)
    }

    /// Configured parser for argument values
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .arg(
    ///         clap::Arg::new("port")
    ///             .value_parser(clap::value_parser!(usize))
    ///     );
    /// let value_parser = cmd.get_arguments()
    ///     .find(|a| a.get_id() == "port").unwrap()
    ///     .get_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_value_parser(&self) -> &super::ValueParser {
        if let Some(value_parser) = self.value_parser.as_ref() {
            value_parser
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::string();
            &DEFAULT
        }
    }

    /// Report whether [`Arg::global`] is set
    pub fn is_global_set(&self) -> bool {
        self.is_set(ArgSettings::Global)
    }

    /// Report whether [`Arg::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(ArgSettings::NextLineHelp)
    }

    /// Report whether [`Arg::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(ArgSettings::Hidden)
    }

    /// Report whether [`Arg::hide_default_value`] is set
    pub fn is_hide_default_value_set(&self) -> bool {
        self.is_set(ArgSettings::HideDefaultValue)
    }

    /// Report whether [`Arg::hide_possible_values`] is set
    pub fn is_hide_possible_values_set(&self) -> bool {
        self.is_set(ArgSettings::HidePossibleValues)
    }

    /// Report whether [`Arg::hide_env`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnv)
    }

    /// Report whether [`Arg::hide_env_values`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_values_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnvValues)
    }

    /// Report whether [`Arg::hide_short_help`] is set
    pub fn is_hide_short_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenShortHelp)
    }

    /// Report whether [`Arg::hide_long_help`] is set
    pub fn is_hide_long_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenLongHelp)
    }

    /// Report whether [`Arg::require_equals`] is set
    pub fn is_require_equals_set(&self) -> bool {
        self.is_set(ArgSettings::RequireEquals)
    }

    /// Reports whether [`Arg::exclusive`] is set
    pub fn is_exclusive_set(&self) -> bool {
        self.is_set(ArgSettings::Exclusive)
    }

    /// Report whether [`Arg::trailing_var_arg`] is set
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(ArgSettings::TrailingVarArg)
    }

    /// Reports whether [`Arg::last`] is set
    pub fn is_last_set(&self) -> bool {
        self.is_set(ArgSettings::Last)
    }

    /// Reports whether [`Arg::ignore_case`] is set
    pub fn is_ignore_case_set(&self) -> bool {
        self.is_set(ArgSettings::IgnoreCase)
    }
}

/// # Internally used only
impl Arg {
    pub(crate) fn _build(&mut self) {
        if self.action.is_none() {
            if self.num_vals == Some(ValueRange::EMPTY) {
                let action = super::ArgAction::SetTrue;
                self.action = Some(action);
            } else {
                let action =
                    if self.is_positional() && self.num_vals.unwrap_or_default().is_unbounded() {
                        // Allow collecting arguments interleaved with flags
                        //
                        // Bounded values are probably a group and the user should explicitly opt-in to
                        // Append
                        super::ArgAction::Append
                    } else {
                        super::ArgAction::Set
                    };
                self.action = Some(action);
            }
        }
        if let Some(action) = self.action.as_ref() {
            if let Some(default_value) = action.default_value() {
                if self.default_vals.is_empty() {
                    self.default_vals = vec![default_value.into()];
                }
            }
            if let Some(default_value) = action.default_missing_value() {
                if self.default_missing_vals.is_empty() {
                    self.default_missing_vals = vec![default_value.into()];
                }
            }
        }

        if self.value_parser.is_none() {
            if let Some(default) = self.action.as_ref().and_then(|a| a.default_value_parser()) {
                self.value_parser = Some(default);
            } else {
                self.value_parser = Some(super::ValueParser::string());
            }
        }

        let val_names_len = self.val_names.len();
        if val_names_len > 1 {
            self.num_vals.get_or_insert(val_names_len.into());
        } else {
            let nargs = if self.get_action().takes_values() {
                ValueRange::SINGLE
            } else {
                ValueRange::EMPTY
            };
            self.num_vals.get_or_insert(nargs);
        }
    }

    // Used for positionals when printing
    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

    /// Write the values such as <name1> <name2>
    fn render_arg_val(&self, required: bool) -> String {
        let mut rendered = String::new();

        let num_vals = self.get_num_args().unwrap_or_else(|| 1.into());

        let mut val_names = if self.val_names.is_empty() {
            vec![self.id.as_internal_str().to_owned()]
        } else {
            self.val_names.clone()
        };
        if val_names.len() == 1 {
            let min = num_vals.min_values().max(1);
            let val_name = val_names.pop().unwrap();
            val_names = vec![val_name; min];
        }

        debug_assert!(self.is_takes_value_set());
        for (n, val_name) in val_names.iter().enumerate() {
            let arg_name = if self.is_positional() && (num_vals.min_values() == 0 || !required) {
                format!("[{}]", val_name)
            } else {
                format!("<{}>", val_name)
            };

            if n != 0 {
                rendered.push(' ');
            }
            rendered.push_str(&arg_name);
        }

        let mut extra_values = false;
        extra_values |= val_names.len() < num_vals.max_values();
        if self.is_positional() && matches!(*self.get_action(), ArgAction::Append) {
            extra_values = true;
        }
        if extra_values {
            rendered.push_str("...");
        }

        rendered
    }

src/parser/arg_matcher.rs (line 192)

    pub(crate) fn needs_more_vals(&self, o: &Arg) -> bool {
        let num_pending = self
            .pending
            .as_ref()
            .and_then(|p| (p.id == *o.get_id()).then(|| p.raw_vals.len()))
            .unwrap_or(0);
        debug!(
            "ArgMatcher::needs_more_vals: o={}, pending={}",
            o.get_id(),
            num_pending
        );
        let expected = o.get_num_args().expect(INTERNAL_ERROR_MSG);
        debug!(
            "ArgMatcher::needs_more_vals: expected={}, actual={}",
            expected, num_pending
        );
        expected.accepts_more(num_pending)
    }

src/parser/parser.rs (line 1307)

    fn verify_num_args(&self, arg: &Arg, raw_vals: &[OsString]) -> ClapResult<()> {
        if self.cmd.is_ignore_errors_set() {
            return Ok(());
        }

        let actual = raw_vals.len();
        let expected = arg.get_num_args().expect(INTERNAL_ERROR_MSG);

        if 0 < expected.min_values() && actual == 0 {
            // Issue 665 (https://github.com/clap-rs/clap/issues/665)
            // Issue 1105 (https://github.com/clap-rs/clap/issues/1105)
            return Err(ClapError::empty_value(
                self.cmd,
                &super::get_possible_values_cli(arg)
                    .iter()
                    .filter(|pv| !pv.is_hide_set())
                    .map(|n| n.get_name().to_owned())
                    .collect::<Vec<_>>(),
                arg.to_string(),
            ));
        } else if let Some(expected) = expected.num_values() {
            if expected != actual {
                debug!("Validator::validate_arg_num_vals: Sending error WrongNumberOfValues");
                return Err(ClapError::wrong_number_of_values(
                    self.cmd,
                    arg.to_string(),
                    expected,
                    actual,
                    Usage::new(self.cmd).create_usage_with_title(&[]),
                ));
            }
        } else if actual < expected.min_values() {
            return Err(ClapError::too_few_values(
                self.cmd,
                arg.to_string(),
                expected.min_values(),
                actual,
                Usage::new(self.cmd).create_usage_with_title(&[]),
            ));
        } else if expected.max_values() < actual {
            debug!("Validator::validate_arg_num_vals: Sending error TooManyValues");
            return Err(ClapError::too_many_values(
                self.cmd,
                raw_vals
                    .last()
                    .expect(INTERNAL_ERROR_MSG)
                    .to_string_lossy()
                    .into_owned(),
                arg.to_string(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            ));
        }

        Ok(())
    }

src/builder/debug_asserts.rs (line 597)

fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn get_value_delimiter(&self) -> Option<char>

Get the delimiter between multiple values

Examples found in repository

src/builder/debug_asserts.rs (line 856)

fn assert_defaults<'d>(
    arg: &Arg,
    field: &'static str,
    defaults: impl IntoIterator<Item = &'d OsStr>,
) {
    for default_os in defaults {
        let value_parser = arg.get_value_parser();
        let assert_cmd = Command::new("assert");
        if let Some(delim) = arg.get_value_delimiter() {
            let default_os = RawOsStr::new(default_os);
            for part in default_os.split(delim) {
                if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), &part.to_os_str())
                {
                    panic!(
                        "Argument `{}`'s {}={:?} failed validation: {}",
                        arg.get_id(),
                        field,
                        part.to_str_lossy(),
                        err
                    );
                }
            }
        } else if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), default_os) {
            panic!(
                "Argument `{}`'s {}={:?} failed validation: {}",
                arg.get_id(),
                field,
                default_os,
                err
            );
        }
    }
}

src/parser/parser.rs (line 1154)

    fn react(
        &self,
        ident: Option<Identifier>,
        source: ValueSource,
        arg: &Arg,
        mut raw_vals: Vec<OsString>,
        mut trailing_idx: Option<usize>,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<ParseResult> {
        ok!(self.resolve_pending(matcher));

        debug!(
            "Parser::react action={:?}, identifier={:?}, source={:?}",
            arg.get_action(),
            ident,
            source
        );

        // Process before `default_missing_values` to avoid it counting as values from the command
        // line
        if source == ValueSource::CommandLine {
            ok!(self.verify_num_args(arg, &raw_vals));
        }

        if raw_vals.is_empty() {
            // We assume this case is valid: require equals, but min_vals == 0.
            if !arg.default_missing_vals.is_empty() {
                debug!("Parser::react: has default_missing_vals");
                trailing_idx = None;
                raw_vals.extend(
                    arg.default_missing_vals
                        .iter()
                        .map(|s| s.as_os_str().to_owned()),
                );
            }
        }

        if let Some(val_delim) = arg.get_value_delimiter() {
            if self.cmd.is_dont_delimit_trailing_values_set() && trailing_idx == Some(0) {
                // Nothing to do
            } else {
                let mut split_raw_vals = Vec::with_capacity(raw_vals.len());
                for (i, raw_val) in raw_vals.into_iter().enumerate() {
                    let raw_val = RawOsString::new(raw_val);
                    if !raw_val.contains(val_delim)
                        || (self.cmd.is_dont_delimit_trailing_values_set()
                            && trailing_idx == Some(i))
                    {
                        split_raw_vals.push(raw_val.into_os_string());
                    } else {
                        split_raw_vals
                            .extend(raw_val.split(val_delim).map(|x| x.to_os_str().into_owned()));
                    }
                }
                raw_vals = split_raw_vals
            }
        }

        match arg.get_action() {
            ArgAction::Set => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Append => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetTrue => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("true")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetFalse => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("false")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Count => {
                let raw_vals = if raw_vals.is_empty() {
                    let existing_value = *matcher
                        .get_one::<crate::builder::CountType>(arg.get_id().as_str())
                        .unwrap_or(&0);
                    let next_value = existing_value.saturating_add(1);
                    vec![OsString::from(next_value.to_string())]
                } else {
                    raw_vals
                };

                matcher.remove(arg.get_id());
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Help => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Help: use_long={}", use_long);
                Err(self.help_err(use_long))
            }
            ArgAction::Version => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Version: use_long={}", use_long);
                Err(self.version_err(use_long))
            }
        }
    }

pub fn get_index(&self) -> Option<usize>

Get the index of this argument, if any

Examples found in repository

src/output/help_template.rs (line 956)

fn positional_sort_key(arg: &Arg) -> (usize, String) {
    (arg.get_index().unwrap_or(0), String::new())
}

src/builder/command.rs (line 3913)

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

src/output/usage.rs (line 251)

    pub(crate) fn get_args(&self, incls: &[Id], force_optional: bool) -> Vec<StyledStr> {
        debug!("Usage::get_args: incls={:?}", incls,);

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => false,
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!("Usage::get_args: unrolled_reqs={:?}", unrolled_reqs);

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let stylized = arg.stylized(Some(!force_optional));
                if let Some(index) = arg.get_index() {
                    let new_len = index + 1;
                    if required_positionals.len() < new_len {
                        required_positionals.resize(new_len, None);
                    }
                    required_positionals[index] = Some(stylized);
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        for pos in self.cmd.get_positionals() {
            if pos.is_hide_set() {
                continue;
            }
            if required_groups_members.contains(pos.get_id()) {
                continue;
            }

            let index = pos.get_index().unwrap();
            let new_len = index + 1;
            if required_positionals.len() < new_len {
                required_positionals.resize(new_len, None);
            }
            if required_positionals[index].is_some() {
                if pos.is_last_set() {
                    let styled = required_positionals[index].take().unwrap();
                    let mut new = StyledStr::new();
                    new.literal("-- ");
                    new.extend(styled.into_iter());
                    required_positionals[index] = Some(new);
                }
            } else {
                let mut styled;
                if pos.is_last_set() {
                    styled = StyledStr::new();
                    styled.literal("[-- ");
                    styled.extend(pos.stylized(Some(true)).into_iter());
                    styled.literal("]");
                } else {
                    styled = pos.stylized(Some(false));
                }
                required_positionals[index] = Some(styled);
            }
            if pos.is_last_set() && force_optional {
                required_positionals[index] = None;
            }
        }

        let mut ret_val = Vec::new();
        if !force_optional {
            ret_val.extend(required_opts);
            ret_val.extend(required_groups);
        }
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_args: ret_val={:?}", ret_val);
        ret_val
    }

    pub(crate) fn get_required_usage_from(
        &self,
        incls: &[Id],
        matcher: Option<&ArgMatcher>,
        incl_last: bool,
    ) -> Vec<StyledStr> {
        debug!(
            "Usage::get_required_usage_from: incls={:?}, matcher={:?}, incl_last={:?}",
            incls,
            matcher.is_some(),
            incl_last
        );

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => {
                        if let Some(matcher) = matcher {
                            matcher.check_explicit(a, val)
                        } else {
                            false
                        }
                    }
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!(
            "Usage::get_required_usage_from: unrolled_reqs={:?}",
            unrolled_reqs
        );

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let is_present = matcher
                    .map(|m| {
                        group_members
                            .iter()
                            .any(|arg| m.check_explicit(arg, &ArgPredicate::IsPresent))
                    })
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} group is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let is_present = matcher
                    .map(|m| m.check_explicit(req, &ArgPredicate::IsPresent))
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} arg is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let stylized = arg.stylized(Some(true));
                if let Some(index) = arg.get_index() {
                    if !arg.is_last_set() || incl_last {
                        let new_len = index + 1;
                        if required_positionals.len() < new_len {
                            required_positionals.resize(new_len, None);
                        }
                        required_positionals[index] = Some(stylized);
                    }
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        let mut ret_val = Vec::new();
        ret_val.extend(required_opts);
        ret_val.extend(required_groups);
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_required_usage_from: ret_val={:?}", ret_val);
        ret_val
    }

src/parser/validator.rs (line 286)

    fn validate_required(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_required: required={:?}", self.required);
        self.gather_requires(matcher);

        let mut missing_required = Vec::new();
        let mut highest_index = 0;

        let is_exclusive_present = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .any(|id| {
                self.cmd
                    .find(id)
                    .map(|arg| arg.is_exclusive_set())
                    .unwrap_or_default()
            });
        debug!(
            "Validator::validate_required: is_exclusive_present={}",
            is_exclusive_present
        );

        for arg_or_group in self
            .required
            .iter()
            .filter(|r| !matcher.check_explicit(r, &ArgPredicate::IsPresent))
        {
            debug!("Validator::validate_required:iter:aog={:?}", arg_or_group);
            if let Some(arg) = self.cmd.find(arg_or_group) {
                debug!("Validator::validate_required:iter: This is an arg");
                if !is_exclusive_present && !self.is_missing_required_ok(arg, matcher, conflicts) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        arg.get_id()
                    );
                    missing_required.push(arg.get_id().clone());
                    if !arg.is_last_set() {
                        highest_index = highest_index.max(arg.get_index().unwrap_or(0));
                    }
                }
            } else if let Some(group) = self.cmd.find_group(arg_or_group) {
                debug!("Validator::validate_required:iter: This is a group");
                if !self
                    .cmd
                    .unroll_args_in_group(&group.id)
                    .iter()
                    .any(|a| matcher.check_explicit(a, &ArgPredicate::IsPresent))
                {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        group.get_id()
                    );
                    missing_required.push(group.get_id().clone());
                }
            }
        }

        // Validate the conditionally required args
        for a in self
            .cmd
            .get_arguments()
            .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
        {
            let mut required = false;

            for (other, val) in &a.r_ifs {
                if matcher.check_explicit(other, &ArgPredicate::Equals(val.into())) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        a.get_id()
                    );
                    required = true;
                }
            }

            let match_all = a.r_ifs_all.iter().all(|(other, val)| {
                matcher.check_explicit(other, &ArgPredicate::Equals(val.into()))
            });
            if match_all && !a.r_ifs_all.is_empty() {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if (!a.r_unless.is_empty() || !a.r_unless_all.is_empty())
                && self.fails_arg_required_unless(a, matcher)
            {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if required {
                missing_required.push(a.get_id().clone());
                if !a.is_last_set() {
                    highest_index = highest_index.max(a.get_index().unwrap_or(0));
                }
            }
        }

        // For display purposes, include all of the preceding positional arguments
        if !self.cmd.is_allow_missing_positional_set() {
            for pos in self
                .cmd
                .get_positionals()
                .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
            {
                if pos.get_index() < Some(highest_index) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        pos.get_id()
                    );
                    missing_required.push(pos.get_id().clone());
                }
            }
        }

        if !missing_required.is_empty() {
            ok!(self.missing_required_error(matcher, missing_required));
        }

        Ok(())
    }

src/builder/debug_asserts.rs (line 136)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

src/parser/parser.rs (line 319)

    pub(crate) fn get_matches_with(
        &mut self,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        mut args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<()> {
        debug!("Parser::get_matches_with");
        // Verify all positional assertions pass

        let mut subcmd_name: Option<String> = None;
        let mut keep_state = false;
        let mut parse_state = ParseState::ValuesDone;
        let mut pos_counter = 1;

        // Already met any valid arg(then we shouldn't expect subcommands after it).
        let mut valid_arg_found = false;
        // If the user already passed '--'. Meaning only positional args follow.
        let mut trailing_values = false;

        // Count of positional args
        let positional_count = self
            .cmd
            .get_keymap()
            .keys()
            .filter(|x| x.is_position())
            .count();
        // If any arg sets .last(true)
        let contains_last = self.cmd.get_arguments().any(|x| x.is_last_set());

        while let Some(arg_os) = raw_args.next(&mut args_cursor) {
            // Recover the replaced items if any.
            if let Some(replaced_items) = arg_os
                .to_value()
                .ok()
                .and_then(|a| self.cmd.get_replacement(a))
            {
                debug!(
                    "Parser::get_matches_with: found replacer: {:?}, target: {:?}",
                    arg_os, replaced_items
                );
                raw_args.insert(&args_cursor, replaced_items);
                continue;
            }

            debug!(
                "Parser::get_matches_with: Begin parsing '{:?}' ({:?})",
                arg_os.to_value_os(),
                arg_os.to_value_os().as_raw_bytes()
            );

            // Has the user already passed '--'? Meaning only positional args follow
            if !trailing_values {
                if self.cmd.is_subcommand_precedence_over_arg_set()
                    || !matches!(parse_state, ParseState::Opt(_) | ParseState::Pos(_))
                {
                    // Does the arg match a subcommand name, or any of its aliases (if defined)
                    let sc_name = self.possible_subcommand(arg_os.to_value(), valid_arg_found);
                    debug!("Parser::get_matches_with: sc={:?}", sc_name);
                    if let Some(sc_name) = sc_name {
                        if sc_name == "help" && !self.cmd.is_disable_help_subcommand_set() {
                            ok!(self.parse_help_subcommand(raw_args.remaining(&mut args_cursor)));
                            unreachable!("`parse_help_subcommand` always errors");
                        } else {
                            subcmd_name = Some(sc_name.to_owned());
                        }
                        break;
                    }
                }

                if arg_os.is_escape() {
                    if matches!(&parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
                        self.cmd[opt].is_allow_hyphen_values_set())
                    {
                        // ParseResult::MaybeHyphenValue, do nothing
                    } else {
                        debug!("Parser::get_matches_with: setting TrailingVals=true");
                        trailing_values = true;
                        matcher.start_trailing();
                        continue;
                    }
                } else if let Some((long_arg, long_value)) = arg_os.to_long() {
                    let parse_result = ok!(self.parse_long_arg(
                        matcher,
                        long_arg,
                        long_value,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    debug!(
                        "Parser::get_matches_with: After parse_long_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            unreachable!("`to_long` always has the flag specified")
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            debug!(
                                "Parser::get_matches_with: FlagSubCommand found in long arg {:?}",
                                &name
                            );
                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            let remaining_args: Vec<_> =
                                raw_args.remaining(&mut args_cursor).collect();
                            return Err(self.did_you_mean_error(
                                &arg,
                                matcher,
                                &remaining_args,
                                trailing_values,
                            ));
                        }
                        ParseResult::UnneededAttachedValue { rest, used, arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::too_many_values(
                                self.cmd,
                                rest,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&used),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::AttachedValueNotConsumed => {
                            unreachable!()
                        }
                    }
                } else if let Some(short_arg) = arg_os.to_short() {
                    // Arg looks like a short flag, and not a possible number

                    // Try to parse short args like normal, if allow_hyphen_values or
                    // AllowNegativeNumbers is set, parse_short_arg will *not* throw
                    // an error, and instead return Ok(None)
                    let parse_result = ok!(self.parse_short_arg(
                        matcher,
                        short_arg,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    // If it's None, we then check if one of those two AppSettings was set
                    debug!(
                        "Parser::get_matches_with: After parse_short_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            // Is a single dash `-`, try positional.
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            // If there are more short flags to be processed, we should keep the state, and later
                            // revisit the current group of short flags skipping the subcommand.
                            keep_state = self
                                .flag_subcmd_at
                                .map(|at| {
                                    raw_args
                                        .seek(&mut args_cursor, clap_lex::SeekFrom::Current(-1));
                                    // Since we are now saving the current state, the number of flags to skip during state recovery should
                                    // be the current index (`cur_idx`) minus ONE UNIT TO THE LEFT of the starting position.
                                    self.flag_subcmd_skip = self.cur_idx.get() - at + 1;
                                })
                                .is_some();

                            debug!(
                                "Parser::get_matches_with:FlagSubCommandShort: subcmd_name={}, keep_state={}, flag_subcmd_skip={}",
                                name,
                                keep_state,
                                self.flag_subcmd_skip
                            );

                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            // We already know it looks like a flag
                            let suggested_trailing_arg =
                                !trailing_values && self.cmd.has_positionals();
                            return Err(ClapError::unknown_argument(
                                self.cmd,
                                arg,
                                None,
                                suggested_trailing_arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::UnneededAttachedValue { .. }
                        | ParseResult::AttachedValueNotConsumed => unreachable!(),
                    }
                }

                if let ParseState::Opt(id) = &parse_state {
                    // Assume this is a value of a previous arg.

                    // get the option so we can check the settings
                    let arg = &self.cmd[id];
                    let parse_result = if let Some(parse_result) =
                        self.check_terminator(arg, arg_os.to_value_os())
                    {
                        parse_result
                    } else {
                        let trailing_values = false;
                        let arg_values = matcher.pending_values_mut(id, None, trailing_values);
                        arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                        if matcher.needs_more_vals(arg) {
                            ParseResult::Opt(arg.get_id().clone())
                        } else {
                            ParseResult::ValuesDone
                        }
                    };
                    parse_state = match parse_result {
                        ParseResult::Opt(id) => ParseState::Opt(id),
                        ParseResult::ValuesDone => ParseState::ValuesDone,
                        _ => unreachable!(),
                    };
                    // get the next value from the iterator
                    continue;
                }
            }

            // Correct pos_counter.
            pos_counter = {
                let is_second_to_last = pos_counter + 1 == positional_count;

                // The last positional argument, or second to last positional
                // argument may be set to .multiple_values(true) or `.multiple_occurrences(true)`
                let low_index_mults = is_second_to_last
                    && self.cmd.get_positionals().any(|a| {
                        a.is_multiple() && (positional_count != a.get_index().unwrap_or(0))
                    })
                    && self
                        .cmd
                        .get_positionals()
                        .last()
                        .map_or(false, |p_name| !p_name.is_last_set());

                let missing_pos = self.cmd.is_allow_missing_positional_set()
                    && is_second_to_last
                    && !trailing_values;

                debug!(
                    "Parser::get_matches_with: Positional counter...{}",
                    pos_counter
                );
                debug!(
                    "Parser::get_matches_with: Low index multiples...{:?}",
                    low_index_mults
                );

                if low_index_mults || missing_pos {
                    let skip_current = if let Some(n) = raw_args.peek(&args_cursor) {
                        if let Some(arg) = self
                            .cmd
                            .get_positionals()
                            .find(|a| a.get_index() == Some(pos_counter))
                        {
                            // If next value looks like a new_arg or it's a
                            // subcommand, skip positional argument under current
                            // pos_counter(which means current value cannot be a
                            // positional argument with a value next to it), assume
                            // current value matches the next arg.
                            self.is_new_arg(&n, arg)
                                || self
                                    .possible_subcommand(n.to_value(), valid_arg_found)
                                    .is_some()
                        } else {
                            true
                        }
                    } else {
                        true
                    };

                    if skip_current {
                        debug!("Parser::get_matches_with: Bumping the positional counter...");
                        pos_counter + 1
                    } else {
                        pos_counter
                    }
                } else if trailing_values
                    && (self.cmd.is_allow_missing_positional_set() || contains_last)
                {
                    // Came to -- and one positional has .last(true) set, so we go immediately
                    // to the last (highest index) positional
                    debug!("Parser::get_matches_with: .last(true) and --, setting last pos");
                    positional_count
                } else {
                    pos_counter
                }
            };

            if let Some(arg) = self.cmd.get_keymap().get(&pos_counter) {
                if arg.is_last_set() && !trailing_values {
                    let _ = self.resolve_pending(matcher);
                    // Its already considered a positional, we don't need to suggest turning it
                    // into one
                    let suggested_trailing_arg = false;
                    return Err(ClapError::unknown_argument(
                        self.cmd,
                        arg_os.display().to_string(),
                        None,
                        suggested_trailing_arg,
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }

                if arg.is_trailing_var_arg_set() {
                    trailing_values = true;
                }

                if matcher.pending_arg_id() != Some(arg.get_id()) || !arg.is_multiple_values_set() {
                    ok!(self.resolve_pending(matcher));
                }
                if let Some(_parse_result) = self.check_terminator(arg, arg_os.to_value_os()) {
                    debug!(
                        "Parser::get_matches_with: ignoring terminator result {:?}",
                        _parse_result
                    );
                } else {
                    let arg_values = matcher.pending_values_mut(
                        arg.get_id(),
                        Some(Identifier::Index),
                        trailing_values,
                    );
                    arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                }

                // Only increment the positional counter if it doesn't allow multiples
                if !arg.is_multiple() {
                    pos_counter += 1;
                    parse_state = ParseState::ValuesDone;
                } else {
                    parse_state = ParseState::Pos(arg.get_id().clone());
                }
                valid_arg_found = true;
            } else if let Some(external_parser) =
                self.cmd.get_external_subcommand_value_parser().cloned()
            {
                // Get external subcommand name
                let sc_name = match arg_os.to_value() {
                    Ok(s) => s.to_owned(),
                    Err(_) => {
                        let _ = self.resolve_pending(matcher);
                        return Err(ClapError::invalid_utf8(
                            self.cmd,
                            Usage::new(self.cmd).create_usage_with_title(&[]),
                        ));
                    }
                };

                // Collect the external subcommand args
                let mut sc_m = ArgMatcher::new(self.cmd);
                sc_m.start_occurrence_of_external(self.cmd);

                for raw_val in raw_args.remaining(&mut args_cursor) {
                    let val = ok!(external_parser.parse_ref(self.cmd, None, raw_val));
                    let external_id = Id::from_static_ref(Id::EXTERNAL);
                    sc_m.add_val_to(&external_id, val, raw_val.to_os_string());
                }

                matcher.subcommand(SubCommand {
                    name: sc_name,
                    matches: sc_m.into_inner(),
                });

                ok!(self.resolve_pending(matcher));
                #[cfg(feature = "env")]
                ok!(self.add_env(matcher));
                ok!(self.add_defaults(matcher));
                return Validator::new(self.cmd).validate(parse_state, matcher);
            } else {
                // Start error processing
                let _ = self.resolve_pending(matcher);
                return Err(self.match_arg_error(&arg_os, valid_arg_found, trailing_values));
            }
        }

        if let Some(ref pos_sc_name) = subcmd_name {
            let sc_name = self
                .cmd
                .find_subcommand(pos_sc_name)
                .expect(INTERNAL_ERROR_MSG)
                .get_name()
                .to_owned();
            ok!(self.parse_subcommand(&sc_name, matcher, raw_args, args_cursor, keep_state));
        }

        ok!(self.resolve_pending(matcher));
        #[cfg(feature = "env")]
        ok!(self.add_env(matcher));
        ok!(self.add_defaults(matcher));
        Validator::new(self.cmd).validate(parse_state, matcher)
    }

pub fn get_value_hint(&self) -> ValueHint

Get the value hint of this argument

Examples found in repository

src/builder/debug_asserts.rs (line 265)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn get_env(&self) -> Option<&OsStr>

Available on crate feature env only.

Get the environment variable name specified for this argument, if any

Examples

let arg = Arg::new("foo").env("ENVIRONMENT");
assert_eq!(arg.get_env(), Some(OsStr::new("ENVIRONMENT")));

pub fn get_default_values(&self) -> &[OsStr]

Get the default values specified for this argument, if any

Examples

let arg = Arg::new("foo").default_value("default value");
assert_eq!(arg.get_default_values(), &["default value"]);

pub fn is_positional(&self) -> bool

Checks whether this argument is a positional or not.

Examples

let arg = Arg::new("foo");
assert_eq!(arg.is_positional(), true);

let arg = Arg::new("foo").long("foo");
assert_eq!(arg.is_positional(), false);

Examples found in repository

src/builder/command.rs (line 173)

    fn arg_internal(&mut self, mut arg: Arg) {
        if let Some(current_disp_ord) = self.current_disp_ord.as_mut() {
            if !arg.is_positional() {
                let current = *current_disp_ord;
                arg.disp_ord.get_or_insert(current);
                *current_disp_ord = current + 1;
            }
        }

        arg.help_heading
            .get_or_insert_with(|| self.current_help_heading.clone());
        self.args.push(arg);
    }

    /// Adds multiple [arguments] to the list of valid possibilities.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, arg, Arg};
    /// Command::new("myprog")
    ///     .args([
    ///         arg!("[debug] -d 'turns on debugging info'"),
    ///         Arg::new("input").help("the input file to use")
    ///     ])
    /// # ;
    /// ```
    /// [arguments]: Arg
    #[must_use]
    pub fn args(mut self, args: impl IntoIterator<Item = impl Into<Arg>>) -> Self {
        for arg in args {
            self = self.arg(arg);
        }
        self
    }

    /// Allows one to mutate an [`Arg`] after it's been added to a [`Command`].
    ///
    /// This can be useful for modifying the auto-generated help or version arguments.
    ///
    /// # Panics
    ///
    /// If the argument is undefined
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    ///
    /// let mut cmd = Command::new("foo")
    ///     .arg(Arg::new("bar")
    ///         .short('b')
    ///         .action(ArgAction::SetTrue))
    ///     .mut_arg("bar", |a| a.short('B'));
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "-b"]);
    ///
    /// // Since we changed `bar`'s short to "B" this should err as there
    /// // is no `-b` anymore, only `-B`
    ///
    /// assert!(res.is_err());
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "-B"]);
    /// assert!(res.is_ok());
    /// ```
    #[must_use]
    #[cfg_attr(debug_assertions, track_caller)]
    pub fn mut_arg<F>(mut self, arg_id: impl AsRef<str>, f: F) -> Self
    where
        F: FnOnce(Arg) -> Arg,
    {
        let id = arg_id.as_ref();
        let a = self
            .args
            .remove_by_name(id)
            .unwrap_or_else(|| panic!("Argument `{}` is undefined", id));

        self.args.push(f(a));
        self
    }

    /// Allows one to mutate a [`Command`] after it's been added as a subcommand.
    ///
    /// This can be useful for modifying auto-generated arguments of nested subcommands with
    /// [`Command::mut_arg`].
    ///
    /// # Panics
    ///
    /// If the subcommand is undefined
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    ///
    /// let mut cmd = Command::new("foo")
    ///         .subcommand(Command::new("bar"))
    ///         .mut_subcommand("bar", |subcmd| subcmd.disable_help_flag(true));
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "bar", "--help"]);
    ///
    /// // Since we disabled the help flag on the "bar" subcommand, this should err.
    ///
    /// assert!(res.is_err());
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "bar"]);
    /// assert!(res.is_ok());
    /// ```
    #[must_use]
    pub fn mut_subcommand<F>(mut self, name: impl AsRef<str>, f: F) -> Self
    where
        F: FnOnce(Self) -> Self,
    {
        let name = name.as_ref();
        let pos = self.subcommands.iter().position(|s| s.name == name);

        let subcmd = if let Some(idx) = pos {
            self.subcommands.remove(idx)
        } else {
            panic!("Command `{}` is undefined", name)
        };

        self.subcommands.push(f(subcmd));
        self
    }

    /// Adds an [`ArgGroup`] to the application.
    ///
    /// [`ArgGroup`]s are a family of related arguments.
    /// By placing them in a logical group, you can build easier requirement and exclusion rules.
    ///
    /// Example use cases:
    /// - Make an entire [`ArgGroup`] required, meaning that one (and *only*
    ///   one) argument from that group must be present at runtime.
    /// - Name an [`ArgGroup`] as a conflict to another argument.
    ///   Meaning any of the arguments that belong to that group will cause a failure if present with
    ///   the conflicting argument.
    /// - Ensure exclusion between arguments.
    /// - Extract a value from a group instead of determining exactly which argument was used.
    ///
    /// # Examples
    ///
    /// The following example demonstrates using an [`ArgGroup`] to ensure that one, and only one,
    /// of the arguments from the specified group is present at runtime.
    ///
    /// ```no_run
    /// # use clap::{Command, arg, ArgGroup};
    /// Command::new("cmd")
    ///     .arg(arg!("--set-ver [ver] 'set the version manually'"))
    ///     .arg(arg!("--major 'auto increase major'"))
    ///     .arg(arg!("--minor 'auto increase minor'"))
    ///     .arg(arg!("--patch 'auto increase patch'"))
    ///     .group(ArgGroup::new("vers")
    ///          .args(["set-ver", "major", "minor","patch"])
    ///          .required(true))
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    pub fn group(mut self, group: impl Into<ArgGroup>) -> Self {
        self.groups.push(group.into());
        self
    }

    /// Adds multiple [`ArgGroup`]s to the [`Command`] at once.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, arg, ArgGroup};
    /// Command::new("cmd")
    ///     .arg(arg!("--set-ver [ver] 'set the version manually'"))
    ///     .arg(arg!("--major         'auto increase major'"))
    ///     .arg(arg!("--minor         'auto increase minor'"))
    ///     .arg(arg!("--patch         'auto increase patch'"))
    ///     .arg(arg!("-c [FILE]       'a config file'"))
    ///     .arg(arg!("-i [IFACE]      'an interface'"))
    ///     .groups([
    ///         ArgGroup::new("vers")
    ///             .args(["set-ver", "major", "minor","patch"])
    ///             .required(true),
    ///         ArgGroup::new("input")
    ///             .args(["c", "i"])
    ///     ])
    /// # ;
    /// ```
    #[must_use]
    pub fn groups(mut self, groups: impl IntoIterator<Item = impl Into<ArgGroup>>) -> Self {
        for g in groups.into_iter() {
            self = self.group(g.into());
        }
        self
    }

    /// Adds a subcommand to the list of valid possibilities.
    ///
    /// Subcommands are effectively sub-[`Command`]s, because they can contain their own arguments,
    /// subcommands, version, usage, etc. They also function just like [`Command`]s, in that they get
    /// their own auto generated help, version, and usage.
    ///
    /// A subcommand's [`Command::name`] will be used for:
    /// - The argument the user passes in
    /// - Programmatically looking up the subcommand
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("config")
    ///         .about("Controls configuration features")
    ///         .arg(arg!("<config> 'Required configuration file to use'")))
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    pub fn subcommand(self, subcmd: impl Into<Command>) -> Self {
        let subcmd = subcmd.into();
        self.subcommand_internal(subcmd)
    }

    fn subcommand_internal(mut self, mut subcmd: Self) -> Self {
        if let Some(current_disp_ord) = self.current_disp_ord.as_mut() {
            let current = *current_disp_ord;
            subcmd.disp_ord.get_or_insert(current);
            *current_disp_ord = current + 1;
        }
        self.subcommands.push(subcmd);
        self
    }

    /// Adds multiple subcommands to the list of valid possibilities.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// # Command::new("myprog")
    /// .subcommands( [
    ///        Command::new("config").about("Controls configuration functionality")
    ///                                 .arg(Arg::new("config_file")),
    ///        Command::new("debug").about("Controls debug functionality")])
    /// # ;
    /// ```
    /// [`IntoIterator`]: std::iter::IntoIterator
    #[must_use]
    pub fn subcommands(mut self, subcmds: impl IntoIterator<Item = impl Into<Self>>) -> Self {
        for subcmd in subcmds {
            self = self.subcommand(subcmd);
        }
        self
    }

    /// Catch problems earlier in the development cycle.
    ///
    /// Most error states are handled as asserts under the assumption they are programming mistake
    /// and not something to handle at runtime.  Rather than relying on tests (manual or automated)
    /// that exhaustively test your CLI to ensure the asserts are evaluated, this will run those
    /// asserts in a way convenient for running as a test.
    ///
    /// **Note::** This will not help with asserts in [`ArgMatches`], those will need exhaustive
    /// testing of your CLI.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// fn cmd() -> Command {
    ///     Command::new("foo")
    ///         .arg(
    ///             Arg::new("bar").short('b').action(ArgAction::SetTrue)
    ///         )
    /// }
    ///
    /// #[test]
    /// fn verify_app() {
    ///     cmd().debug_assert();
    /// }
    ///
    /// fn main() {
    ///     let m = cmd().get_matches_from(vec!["foo", "-b"]);
    ///     println!("{}", *m.get_one::<bool>("bar").expect("defaulted by clap"));
    /// }
    /// ```
    pub fn debug_assert(mut self) {
        self.build();
    }

    /// Custom error message for post-parsing validation
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("myprog");
    /// let err = cmd.error(ErrorKind::InvalidValue, "Some failure case");
    /// ```
    pub fn error(&mut self, kind: ErrorKind, message: impl std::fmt::Display) -> Error {
        Error::raw(kind, message).format(self)
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::try_get_matches_from_mut`]: Command::try_get_matches_from_mut()
    #[inline]
    pub fn get_matches(self) -> ArgMatches {
        self.get_matches_from(&mut env::args_os())
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// Like [`Command::get_matches`] but doesn't consume the `Command`.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let mut cmd = Command::new("myprog")
    ///     // Args and options go here...
    ///     ;
    /// let matches = cmd.get_matches_mut();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::get_matches`]: Command::get_matches()
    pub fn get_matches_mut(&mut self) -> ArgMatches {
        self.try_get_matches_from_mut(&mut env::args_os())
            .unwrap_or_else(|e| e.exit())
    }

    /// Parse [`env::args_os`], returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a
    /// [`ErrorKind::DisplayHelp`] or [`ErrorKind::DisplayVersion`] respectively. You must call
    /// [`Error::exit`] or perform a [`std::process::exit`].
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches()
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    #[inline]
    pub fn try_get_matches(self) -> ClapResult<ArgMatches> {
        // Start the parsing
        self.try_get_matches_from(&mut env::args_os())
    }

    /// Parse the specified arguments, exiting on failure.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches_from(arg_vec);
    /// ```
    /// [`Command::get_matches`]: Command::get_matches()
    /// [`clap::Result`]: Result
    /// [`Vec`]: std::vec::Vec
    pub fn get_matches_from<I, T>(mut self, itr: I) -> ArgMatches
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr).unwrap_or_else(|e| {
            drop(self);
            e.exit()
        })
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches_from(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::get_matches_from`]: Command::get_matches_from()
    /// [`Command::try_get_matches`]: Command::try_get_matches()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Error`]: crate::Error
    /// [`Error::exit`]: crate::Error::exit()
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    /// [`clap::Result`]: Result
    pub fn try_get_matches_from<I, T>(mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr)
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// Like [`Command::try_get_matches_from`] but doesn't consume the `Command`.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let mut cmd = Command::new("myprog");
    ///     // Args and options go here...
    /// let matches = cmd.try_get_matches_from_mut(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::try_get_matches_from`]: Command::try_get_matches_from()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    pub fn try_get_matches_from_mut<I, T>(&mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut raw_args = clap_lex::RawArgs::new(itr.into_iter());
        let mut cursor = raw_args.cursor();

        if self.settings.is_set(AppSettings::Multicall) {
            if let Some(argv0) = raw_args.next_os(&mut cursor) {
                let argv0 = Path::new(&argv0);
                if let Some(command) = argv0.file_stem().and_then(|f| f.to_str()) {
                    // Stop borrowing command so we can get another mut ref to it.
                    let command = command.to_owned();
                    debug!(
                        "Command::try_get_matches_from_mut: Parsed command {} from argv",
                        command
                    );

                    debug!("Command::try_get_matches_from_mut: Reinserting command into arguments so subcommand parser matches it");
                    raw_args.insert(&cursor, [&command]);
                    debug!("Command::try_get_matches_from_mut: Clearing name and bin_name so that displayed command name starts with applet name");
                    self.name = "".into();
                    self.bin_name = None;
                    return self._do_parse(&mut raw_args, cursor);
                }
            }
        };

        // Get the name of the program (argument 1 of env::args()) and determine the
        // actual file
        // that was used to execute the program. This is because a program called
        // ./target/release/my_prog -a
        // will have two arguments, './target/release/my_prog', '-a' but we don't want
        // to display
        // the full path when displaying help messages and such
        if !self.settings.is_set(AppSettings::NoBinaryName) {
            if let Some(name) = raw_args.next_os(&mut cursor) {
                let p = Path::new(name);

                if let Some(f) = p.file_name() {
                    if let Some(s) = f.to_str() {
                        if self.bin_name.is_none() {
                            self.bin_name = Some(s.to_owned());
                        }
                    }
                }
            }
        }

        self._do_parse(&mut raw_args, cursor)
    }

    /// Prints the short help message (`-h`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    pub fn print_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Prints the long help message (`--help`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_long_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    /// [`BufWriter`]: std::io::BufWriter
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn print_long_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Render the short help message (`-h`) to a [`StyledStr`]
    ///
    /// See also [`Command::render_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        styled
    }

    /// Render the long help message (`--help`) to a [`StyledStr`].
    ///
    /// See also [`Command::render_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_long_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_long_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        styled
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_help`")
    )]
    pub fn write_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_long_help`")
    )]
    pub fn write_long_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    /// Version message rendered as if the user ran `-V`.
    ///
    /// See also [`Command::render_long_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_version(&self) -> String {
        self._render_version(false)
    }

    /// Version message rendered as if the user ran `--version`.
    ///
    /// See also [`Command::render_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_long_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_long_version(&self) -> String {
        self._render_version(true)
    }

    /// Usage statement
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// println!("{}", cmd.render_usage());
    /// ```
    pub fn render_usage(&mut self) -> StyledStr {
        self.render_usage_().unwrap_or_default()
    }

    pub(crate) fn render_usage_(&mut self) -> Option<StyledStr> {
        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing incase we run into a subcommand
        self._build_self(false);

        Usage::new(self).create_usage_with_title(&[])
    }
}

/// # Application-wide Settings
///
/// These settings will apply to the top-level command and all subcommands, by default.  Some
/// settings can be overridden in subcommands.
impl Command {
    /// Specifies that the parser should not assume the first argument passed is the binary name.
    ///
    /// This is normally the case when using a "daemon" style mode.  For shells / REPLs, see
    /// [`Command::multicall`][Command::multicall].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let m = Command::new("myprog")
    ///     .no_binary_name(true)
    ///     .arg(arg!(<cmd> ... "commands to run"))
    ///     .get_matches_from(vec!["command", "set"]);
    ///
    /// let cmds: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
    /// assert_eq!(cmds, ["command", "set"]);
    /// ```
    /// [`try_get_matches_from_mut`]: crate::Command::try_get_matches_from_mut()
    #[inline]
    pub fn no_binary_name(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NoBinaryName)
        } else {
            self.unset_global_setting(AppSettings::NoBinaryName)
        }
    }

    /// Try not to fail on parse errors, like missing option values.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let cmd = Command::new("cmd")
    ///   .ignore_errors(true)
    ///   .arg(arg!(-c --config <FILE> "Sets a custom config file"))
    ///   .arg(arg!(-x --stuff <FILE> "Sets a custom stuff file"))
    ///   .arg(arg!(f: -f "Flag"));
    ///
    /// let r = cmd.try_get_matches_from(vec!["cmd", "-c", "file", "-f", "-x"]);
    ///
    /// assert!(r.is_ok(), "unexpected error: {:?}", r);
    /// let m = r.unwrap();
    /// assert_eq!(m.get_one::<String>("config").unwrap(), "file");
    /// assert!(*m.get_one::<bool>("f").expect("defaulted"));
    /// assert_eq!(m.get_one::<String>("stuff"), None);
    /// ```
    #[inline]
    pub fn ignore_errors(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::IgnoreErrors)
        } else {
            self.unset_global_setting(AppSettings::IgnoreErrors)
        }
    }

    /// Replace prior occurrences of arguments rather than error
    ///
    /// For any argument that would conflict with itself by default (e.g.
    /// [`ArgAction::Set`][ArgAction::Set], it will now override itself.
    ///
    /// This is the equivalent to saying the `foo` arg using [`Arg::overrides_with("foo")`] for all
    /// defined arguments.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [`Arg::overrides_with("foo")`]: crate::Arg::overrides_with()
    #[inline]
    pub fn args_override_self(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::AllArgsOverrideSelf)
        } else {
            self.unset_global_setting(AppSettings::AllArgsOverrideSelf)
        }
    }

    /// Disables the automatic delimiting of values after `--` or when [`Command::trailing_var_arg`]
    /// was used.
    ///
    /// **NOTE:** The same thing can be done manually by setting the final positional argument to
    /// [`Arg::value_delimiter(None)`]. Using this setting is safer, because it's easier to locate
    /// when making changes.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .dont_delimit_trailing_values(true)
    ///     .get_matches();
    /// ```
    ///
    /// [`Arg::value_delimiter(None)`]: crate::Arg::value_delimiter()
    #[inline]
    pub fn dont_delimit_trailing_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DontDelimitTrailingValues)
        } else {
            self.unset_global_setting(AppSettings::DontDelimitTrailingValues)
        }
    }

    /// Sets when to color output.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// **NOTE:** Default behaviour is [`ColorChoice::Auto`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, ColorChoice};
    /// Command::new("myprog")
    ///     .color(ColorChoice::Never)
    ///     .get_matches();
    /// ```
    /// [`ColorChoice::Auto`]: crate::ColorChoice::Auto
    #[cfg(feature = "color")]
    #[inline]
    #[must_use]
    pub fn color(self, color: ColorChoice) -> Self {
        let cmd = self
            .unset_global_setting(AppSettings::ColorAuto)
            .unset_global_setting(AppSettings::ColorAlways)
            .unset_global_setting(AppSettings::ColorNever);
        match color {
            ColorChoice::Auto => cmd.global_setting(AppSettings::ColorAuto),
            ColorChoice::Always => cmd.global_setting(AppSettings::ColorAlways),
            ColorChoice::Never => cmd.global_setting(AppSettings::ColorNever),
        }
    }

    /// Sets the terminal width at which to wrap help messages.
    ///
    /// Using `0` will ignore terminal widths and use source formatting.
    ///
    /// Defaults to current terminal width when `wrap_help` feature flag is enabled.  If the flag
    /// is disabled or it cannot be determined, the default is 100.
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .term_width(80)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn term_width(mut self, width: usize) -> Self {
        self.term_w = Some(width);
        self
    }

    /// Limit the line length for wrapping help when using the current terminal's width.
    ///
    /// This only applies when [`term_width`][Command::term_width] is unset so that the current
    /// terminal's width will be used.  See [`Command::term_width`] for more details.
    ///
    /// Using `0` will ignore terminal widths and use source formatting (default).
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .max_term_width(100)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn max_term_width(mut self, w: usize) -> Self {
        self.max_w = Some(w);
        self
    }

    /// Disables `-V` and `--version` flag.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_version_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-V"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_version_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableVersionFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableVersionFlag)
        }
    }

    /// Specifies to use the version of the current command for all [`subcommands`].
    ///
    /// Defaults to `false`; subcommands have independent version strings from their parents.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .version("v1.1")
    ///     .propagate_version(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches();
    /// // running `$ myprog test --version` will display
    /// // "myprog-test v1.1"
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    #[inline]
    pub fn propagate_version(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::PropagateVersion)
        } else {
            self.unset_global_setting(AppSettings::PropagateVersion)
        }
    }

    /// Places the help string for all arguments and subcommands on the line after them.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .next_line_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn next_line_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NextLineHelp)
        } else {
            self.unset_global_setting(AppSettings::NextLineHelp)
        }
    }

    /// Disables `-h` and `--help` flag.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-h"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_help_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpFlag)
        }
    }

    /// Disables the `help` [`subcommand`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_subcommand(true)
    ///     // Normally, creating a subcommand causes a `help` subcommand to automatically
    ///     // be generated as well
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "help"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::InvalidSubcommand);
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn disable_help_subcommand(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpSubcommand)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpSubcommand)
        }
    }

    /// Disables colorized help messages.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .disable_colored_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn disable_colored_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableColoredHelp)
        } else {
            self.unset_global_setting(AppSettings::DisableColoredHelp)
        }
    }

    /// Panic if help descriptions are omitted.
    ///
    /// **NOTE:** When deriving [`Parser`][crate::Parser], you could instead check this at
    /// compile-time with `#![deny(missing_docs)]`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo").help("It does foo stuff")
    ///         // As required via `help_expected`, a help message was supplied
    ///      )
    /// #    .get_matches();
    /// ```
    ///
    /// # Panics
    ///
    /// ```rust,no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo")
    ///         // Someone forgot to put .about("...") here
    ///         // Since the setting `help_expected` is activated, this will lead to
    ///         // a panic (if you are in debug mode)
    ///     )
    /// #   .get_matches();
    ///```
    #[inline]
    pub fn help_expected(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HelpExpected)
        } else {
            self.unset_global_setting(AppSettings::HelpExpected)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn dont_collapse_args_in_usage(self, _yes: bool) -> Self {
        self
    }

    /// Tells `clap` *not* to print possible values when displaying help information.
    ///
    /// This can be useful if there are many values, or they are explained elsewhere.
    ///
    /// To set this per argument, see
    /// [`Arg::hide_possible_values`][crate::Arg::hide_possible_values].
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    #[inline]
    pub fn hide_possible_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HidePossibleValues)
        } else {
            self.unset_global_setting(AppSettings::HidePossibleValues)
        }
    }

    /// Allow partial matches of long arguments or their [aliases].
    ///
    /// For example, to match an argument named `--test`, one could use `--t`, `--te`, `--tes`, and
    /// `--test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match
    /// `--te` to `--test` there could not also be another argument or alias `--temp` because both
    /// start with `--te`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_long_args(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferLongArgs)
        } else {
            self.unset_global_setting(AppSettings::InferLongArgs)
        }
    }

    /// Allow partial matches of [subcommand] names and their [aliases].
    ///
    /// For example, to match a subcommand named `test`, one could use `t`, `te`, `tes`, and
    /// `test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match `te`
    /// to `test` there could not also be a subcommand or alias `temp` because both start with `te`
    ///
    /// **CAUTION:** This setting can interfere with [positional/free arguments], take care when
    /// designing CLIs which allow inferred subcommands and have potential positional/free
    /// arguments whose values could start with the same characters as subcommands. If this is the
    /// case, it's recommended to use settings such as [`Command::args_conflicts_with_subcommands`] in
    /// conjunction with this setting.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("prog")
    ///     .infer_subcommands(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches_from(vec![
    ///         "prog", "te"
    ///     ]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    ///
    /// [subcommand]: crate::Command::subcommand()
    /// [positional/free arguments]: crate::Arg::index()
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_subcommands(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferSubcommands)
        } else {
            self.unset_global_setting(AppSettings::InferSubcommands)
        }
    }
}

/// # Command-specific Settings
///
/// These apply only to the current command and are not inherited by subcommands.
impl Command {
    /// (Re)Sets the program's name.
    ///
    /// See [`Command::new`] for more details.
    ///
    /// # Examples
    ///
    /// ```ignore
    /// let cmd = clap::command!()
    ///     .name("foo");
    ///
    /// // continued logic goes here, such as `cmd.get_matches()` etc.
    /// ```
    #[must_use]
    pub fn name(mut self, name: impl Into<Str>) -> Self {
        self.name = name.into();
        self
    }

    /// Overrides the runtime-determined name of the binary for help and error messages.
    ///
    /// This should only be used when absolutely necessary, such as when the binary name for your
    /// application is misleading, or perhaps *not* how the user should invoke your program.
    ///
    /// **Pro-tip:** When building things such as third party `cargo`
    /// subcommands, this setting **should** be used!
    ///
    /// **NOTE:** This *does not* change or set the name of the binary file on
    /// disk. It only changes what clap thinks the name is for the purposes of
    /// error or help messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .bin_name("my_binary")
    /// # ;
    /// ```
    #[must_use]
    pub fn bin_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.bin_name = name.into_resettable().into_option();
        self
    }

    /// Overrides the runtime-determined display name of the program for help and error messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .display_name("my_program")
    /// # ;
    /// ```
    #[must_use]
    pub fn display_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.display_name = name.into_resettable().into_option();
        self
    }

    /// Sets the author(s) for the help message.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_authors!`] to
    /// automatically set your application's author(s) to the same thing as your
    /// crate at compile time.
    ///
    /// **NOTE:** A custom [`help_template`][Command::help_template] is needed for author to show
    /// up.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///      .author("Me, me@mymain.com")
    /// # ;
    /// ```
    #[must_use]
    pub fn author(mut self, author: impl IntoResettable<Str>) -> Self {
        self.author = author.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the short help (`-h`).
    ///
    /// If [`Command::long_about`] is not specified, this message will be displayed for `--help`.
    ///
    /// **NOTE:** Only `Command::about` (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// See also [`crate_description!`](crate::crate_description!).
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .about("Does really amazing things for great people")
    /// # ;
    /// ```
    #[must_use]
    pub fn about(mut self, about: impl IntoResettable<StyledStr>) -> Self {
        self.about = about.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the long help (`--help`).
    ///
    /// If [`Command::about`] is not specified, this message will be displayed for `-h`.
    ///
    /// **NOTE:** Only [`Command::about`] (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_about(
    /// "Does really amazing things to great people. Now let's talk a little
    ///  more in depth about how this subcommand really works. It may take about
    ///  a few lines of text, but that's ok!")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    #[must_use]
    pub fn long_about(mut self, long_about: impl IntoResettable<StyledStr>) -> Self {
        self.long_about = long_about.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated short help (`-h`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_help("Does really amazing things for great people... but be careful with -R!")
    /// # ;
    /// ```
    ///
    #[must_use]
    pub fn after_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated long help (`--help`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_long_help("Does really amazing things to great people... but be careful with -R, \
    ///                      like, for real, be careful with this!")
    /// # ;
    /// ```
    #[must_use]
    pub fn after_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_long_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated short help (`-h`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_help("Some info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated long help (`--help`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_long_help("Some verbose and long info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_long_help = help.into_resettable().into_option();
        self
    }

    /// Sets the version for the short version (`-V`) and help messages.
    ///
    /// If [`Command::long_version`] is not specified, this message will be displayed for `--version`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("v0.1.24")
    /// # ;
    /// ```
    #[must_use]
    pub fn version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.version = ver.into_resettable().into_option();
        self
    }

    /// Sets the version for the long version (`--version`) and help messages.
    ///
    /// If [`Command::version`] is not specified, this message will be displayed for `-V`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_version(
    /// "v0.1.24
    ///  commit: abcdef89726d
    ///  revision: 123
    ///  release: 2
    ///  binary: myprog")
    /// # ;
    /// ```
    #[must_use]
    pub fn long_version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.long_version = ver.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated usage string for help and error messages.
    ///
    /// **NOTE:** Using this setting disables `clap`s "context-aware" usage
    /// strings. After this setting is set, this will be *the only* usage string
    /// displayed to the user!
    ///
    /// **NOTE:** Multiple usage lines may be present in the usage argument, but
    /// some rules need to be followed to ensure the usage lines are formatted
    /// correctly by the default help formatter:
    ///
    /// - Do not indent the first usage line.
    /// - Indent all subsequent usage lines with seven spaces.
    /// - The last line must not end with a newline.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage("myapp [-clDas] <some_file>")
    /// # ;
    /// ```
    ///
    /// Or for multiple usage lines:
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage(
    ///         "myapp -X [-a] [-b] <file>\n       \
    ///          myapp -Y [-c] <file1> <file2>\n       \
    ///          myapp -Z [-d|-e]"
    ///     )
    /// # ;
    /// ```
    ///
    /// [`ArgMatches::usage`]: ArgMatches::usage()
    #[must_use]
    pub fn override_usage(mut self, usage: impl IntoResettable<StyledStr>) -> Self {
        self.usage_str = usage.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated help message (both `-h` and `--help`).
    ///
    /// This should only be used when the auto-generated message does not suffice.
    ///
    /// **NOTE:** This **only** replaces the help message for the current
    /// command, meaning if you are using subcommands, those help messages will
    /// still be auto-generated unless you specify a [`Command::override_help`] for
    /// them as well.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .override_help("myapp v1.0\n\
    ///            Does awesome things\n\
    ///            (C) me@mail.com\n\n\
    ///
    ///            Usage: myapp <opts> <command>\n\n\
    ///
    ///            Options:\n\
    ///            -h, --help       Display this message\n\
    ///            -V, --version    Display version info\n\
    ///            -s <stuff>       Do something with stuff\n\
    ///            -v               Be verbose\n\n\
    ///
    ///            Commands:\n\
    ///            help             Print this message\n\
    ///            work             Do some work")
    /// # ;
    /// ```
    #[must_use]
    pub fn override_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.help_str = help.into_resettable().into_option();
        self
    }

    /// Sets the help template to be used, overriding the default format.
    ///
    /// **NOTE:** The template system is by design very simple. Therefore, the
    /// tags have to be written in the lowercase and without spacing.
    ///
    /// Tags are given inside curly brackets.
    ///
    /// Valid tags are:
    ///
    ///   * `{name}`                - Display name for the (sub-)command.
    ///   * `{bin}`                 - Binary name.
    ///   * `{version}`             - Version number.
    ///   * `{author}`              - Author information.
    ///   * `{author-with-newline}` - Author followed by `\n`.
    ///   * `{author-section}`      - Author preceded and followed by `\n`.
    ///   * `{about}`               - General description (from [`Command::about`] or
    ///                               [`Command::long_about`]).
    ///   * `{about-with-newline}`  - About followed by `\n`.
    ///   * `{about-section}`       - About preceded and followed by '\n'.
    ///   * `{usage-heading}`       - Automatically generated usage heading.
    ///   * `{usage}`               - Automatically generated or given usage string.
    ///   * `{all-args}`            - Help for all arguments (options, flags, positional
    ///                               arguments, and subcommands) including titles.
    ///   * `{options}`             - Help for options.
    ///   * `{positionals}`         - Help for positional arguments.
    ///   * `{subcommands}`         - Help for subcommands.
    ///   * `{tag}`                 - Standard tab sized used within clap
    ///   * `{after-help}`          - Help from [`Command::after_help`] or [`Command::after_long_help`].
    ///   * `{before-help}`         - Help from [`Command::before_help`] or [`Command::before_long_help`].
    ///
    /// # Examples
    ///
    /// For a very brief help:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("{bin} ({version}) - {usage}")
    /// # ;
    /// ```
    ///
    /// For showing more application context:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("\
    /// {before-help}{name} {version}
    /// {author-with-newline}{about-with-newline}
    /// {usage-heading} {usage}
    ///
    /// {all-args}{after-help}
    /// ")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    /// [`Command::long_about`]: Command::long_about()
    /// [`Command::after_help`]: Command::after_help()
    /// [`Command::after_long_help`]: Command::after_long_help()
    /// [`Command::before_help`]: Command::before_help()
    /// [`Command::before_long_help`]: Command::before_long_help()
    #[must_use]
    #[cfg(feature = "help")]
    pub fn help_template(mut self, s: impl IntoResettable<StyledStr>) -> Self {
        self.template = s.into_resettable().into_option();
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.insert(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.remove(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.set(setting);
        self.g_settings.set(setting);
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.unset(setting);
        self.g_settings.unset(setting);
        self
    }

    /// Set the default section heading for future args.
    ///
    /// This will be used for any arg that hasn't had [`Arg::help_heading`] called.
    ///
    /// This is useful if the default `Options` or `Arguments` headings are
    /// not specific enough for one's use case.
    ///
    /// For subcommands, see [`Command::subcommand_help_heading`]
    ///
    /// [`Command::arg`]: Command::arg()
    /// [`Arg::help_heading`]: crate::Arg::help_heading()
    #[inline]
    #[must_use]
    pub fn next_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.current_help_heading = heading.into_resettable().into_option();
        self
    }

    /// Change the starting value for assigning future display orders for ags.
    ///
    /// This will be used for any arg that hasn't had [`Arg::display_order`] called.
    #[inline]
    #[must_use]
    pub fn next_display_order(mut self, disp_ord: impl IntoResettable<usize>) -> Self {
        self.current_disp_ord = disp_ord.into_resettable().into_option();
        self
    }

    /// Replaces an argument or subcommand used on the CLI at runtime with other arguments or subcommands.
    ///
    /// **Note:** This is gated behind [`unstable-replace`](https://github.com/clap-rs/clap/issues/2836)
    ///
    /// When this method is used, `name` is removed from the CLI, and `target`
    /// is inserted in its place. Parsing continues as if the user typed
    /// `target` instead of `name`.
    ///
    /// This can be used to create "shortcuts" for subcommands, or if a
    /// particular argument has the semantic meaning of several other specific
    /// arguments and values.
    ///
    /// # Examples
    ///
    /// We'll start with the "subcommand short" example. In this example, let's
    /// assume we have a program with a subcommand `module` which can be invoked
    /// via `cmd module`. Now let's also assume `module` also has a subcommand
    /// called `install` which can be invoked `cmd module install`. If for some
    /// reason users needed to be able to reach `cmd module install` via the
    /// short-hand `cmd install`, we'd have several options.
    ///
    /// We *could* create another sibling subcommand to `module` called
    /// `install`, but then we would need to manage another subcommand and manually
    /// dispatch to `cmd module install` handling code. This is error prone and
    /// tedious.
    ///
    /// We could instead use [`Command::replace`] so that, when the user types `cmd
    /// install`, `clap` will replace `install` with `module install` which will
    /// end up getting parsed as if the user typed the entire incantation.
    ///
    /// ```rust
    /// # use clap::Command;
    /// let m = Command::new("cmd")
    ///     .subcommand(Command::new("module")
    ///         .subcommand(Command::new("install")))
    ///     .replace("install", &["module", "install"])
    ///     .get_matches_from(vec!["cmd", "install"]);
    ///
    /// assert!(m.subcommand_matches("module").is_some());
    /// assert!(m.subcommand_matches("module").unwrap().subcommand_matches("install").is_some());
    /// ```
    ///
    /// Now let's show an argument example!
    ///
    /// Let's assume we have an application with two flags `--save-context` and
    /// `--save-runtime`. But often users end up needing to do *both* at the
    /// same time. We can add a third flag `--save-all` which semantically means
    /// the same thing as `cmd --save-context --save-runtime`. To implement that,
    /// we have several options.
    ///
    /// We could create this third argument and manually check if that argument
    /// and in our own consumer code handle the fact that both `--save-context`
    /// and `--save-runtime` *should* have been used. But again this is error
    /// prone and tedious. If we had code relying on checking `--save-context`
    /// and we forgot to update that code to *also* check `--save-all` it'd mean
    /// an error!
    ///
    /// Luckily we can use [`Command::replace`] so that when the user types
    /// `--save-all`, `clap` will replace that argument with `--save-context
    /// --save-runtime`, and parsing will continue like normal. Now all our code
    /// that was originally checking for things like `--save-context` doesn't
    /// need to change!
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .replace("--save-all", &["--save-context", "--save-runtime"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// ```
    ///
    /// This can also be used with options, for example if our application with
    /// `--save-*` above also had a `--format=TYPE` option. Let's say it
    /// accepted `txt` or `json` values. However, when `--save-all` is used,
    /// only `--format=json` is allowed, or valid. We could change the example
    /// above to enforce this:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("format")
    ///         .long("format")
    ///         .action(ArgAction::Set)
    ///         .value_parser(["txt", "json"]))
    ///     .replace("--save-all", &["--save-context", "--save-runtime", "--format=json"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// assert_eq!(m.get_one::<String>("format").unwrap(), "json");
    /// ```
    ///
    /// [`Command::replace`]: Command::replace()
    #[inline]
    #[cfg(feature = "unstable-replace")]
    #[must_use]
    pub fn replace(
        mut self,
        name: impl Into<Str>,
        target: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        self.replacers
            .insert(name.into(), target.into_iter().map(Into::into).collect());
        self
    }

    /// Exit gracefully if no arguments are present (e.g. `$ myprog`).
    ///
    /// **NOTE:** [`subcommands`] count as arguments
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command};
    /// Command::new("myprog")
    ///     .arg_required_else_help(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    /// [`Arg::default_value`]: crate::Arg::default_value()
    #[inline]
    pub fn arg_required_else_help(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgRequiredElseHelp)
        } else {
            self.unset_setting(AppSettings::ArgRequiredElseHelp)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_hyphen_values`")
    )]
    pub fn allow_hyphen_values(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowHyphenValues)
        } else {
            self.unset_setting(AppSettings::AllowHyphenValues)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_negative_numbers`")
    )]
    pub fn allow_negative_numbers(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowNegativeNumbers)
        } else {
            self.unset_setting(AppSettings::AllowNegativeNumbers)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::trailing_var_arg`")
    )]
    pub fn trailing_var_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::TrailingVarArg)
        } else {
            self.unset_setting(AppSettings::TrailingVarArg)
        }
    }

    /// Allows one to implement two styles of CLIs where positionals can be used out of order.
    ///
    /// The first example is a CLI where the second to last positional argument is optional, but
    /// the final positional argument is required. Such as `$ prog [optional] <required>` where one
    /// of the two following usages is allowed:
    ///
    /// * `$ prog [optional] <required>`
    /// * `$ prog <required>`
    ///
    /// This would otherwise not be allowed. This is useful when `[optional]` has a default value.
    ///
    /// **Note:** when using this style of "missing positionals" the final positional *must* be
    /// [required] if `--` will not be used to skip to the final positional argument.
    ///
    /// **Note:** This style also only allows a single positional argument to be "skipped" without
    /// the use of `--`. To skip more than one, see the second example.
    ///
    /// The second example is when one wants to skip multiple optional positional arguments, and use
    /// of the `--` operator is OK (but not required if all arguments will be specified anyways).
    ///
    /// For example, imagine a CLI which has three positional arguments `[foo] [bar] [baz]...` where
    /// `baz` accepts multiple values (similar to man `ARGS...` style training arguments).
    ///
    /// With this setting the following invocations are posisble:
    ///
    /// * `$ prog foo bar baz1 baz2 baz3`
    /// * `$ prog foo -- baz1 baz2 baz3`
    /// * `$ prog -- baz1 baz2 baz3`
    ///
    /// # Examples
    ///
    /// Style number one from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1"), None);
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Now the same example, but using a default value for the first optional positional argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1")
    ///         .default_value("something"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1").unwrap(), "something");
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Style number two from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "foo", "bar", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo").unwrap(), "foo");
    /// assert_eq!(m.get_one::<String>("bar").unwrap(), "bar");
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// Now nofice if we don't specify `foo` or `baz` but use the `--` operator.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "--", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo"), None);
    /// assert_eq!(m.get_one::<String>("bar"), None);
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// [required]: crate::Arg::required()
    #[inline]
    pub fn allow_missing_positional(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowMissingPositional)
        } else {
            self.unset_setting(AppSettings::AllowMissingPositional)
        }
    }
}

/// # Subcommand-specific Settings
impl Command {
    /// Sets the short version of the subcommand flag without the preceding `-`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::short`].
    ///
    /// # Examples
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").short_flag('S').arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "-Ss"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    /// [`Arg::short`]: Arg::short()
    #[must_use]
    pub fn short_flag(mut self, short: impl IntoResettable<char>) -> Self {
        self.short_flag = short.into_resettable().into_option();
        self
    }

    /// Sets the long version of the subcommand flag without the preceding `--`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::long`].
    ///
    /// **NOTE:** Any leading `-` characters will be stripped.
    ///
    /// # Examples
    ///
    /// To set `long_flag` use a word containing valid UTF-8 codepoints. If you supply a double leading
    /// `--` such as `--sync` they will be stripped. Hyphens in the middle of the word; however,
    /// will *not* be stripped (i.e. `sync-file` is allowed).
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").long_flag("sync").arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "--sync", "--search"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    ///
    /// [`Arg::long`]: Arg::long()
    #[must_use]
    pub fn long_flag(mut self, long: impl Into<Str>) -> Self {
        self.long_flag = Some(long.into());
        self
    }

    /// Sets a hidden alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name, or this given
    /// alias. This is more efficient and easier than creating multiple hidden subcommands as one
    /// only needs to check for the existence of this command, and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If you're looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_alias`]: Command::visible_alias()
    #[must_use]
    pub fn alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, false));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "hidden" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, false));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "hidden" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, false));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple hidden aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name or any of the
    /// given aliases. This is more efficient, and easier than creating multiple hidden subcommands
    /// as one only needs to check for the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_aliases`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .aliases(["do-stuff", "do-tests", "tests"]))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "do-tests"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_aliases`]: Command::visible_aliases()
    #[must_use]
    pub fn aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), false)));
        self
    }

    /// Add aliases, which function as "hidden" short flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test").short_flag('t')
    ///         .short_flag_aliases(['a', 'b', 'c']))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "-a"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, false));
        }
        self
    }

    /// Add aliases, which function as "hidden" long flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_aliases(["testing", "testall", "test_all"]))
    ///                 .arg(Arg::new("input")
    ///                             .help("the file to add")
    ///                             .required(false))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        for s in names {
            self = self.long_flag_alias(s)
        }
        self
    }

    /// Sets a visible alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or the given alias. This is more efficient and easier
    /// than creating hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, true));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "visible" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::short_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .visible_short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_alias`]: Command::short_flag_alias()
    #[must_use]
    pub fn visible_short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, true));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "visible" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::long_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_alias`]: Command::long_flag_alias()
    #[must_use]
    pub fn visible_long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, true));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple visible aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or any of the given aliases. This is more efficient and easier
    /// than creating multiple hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases, and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_aliases(["do-stuff", "tests"]))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), true)));
        self
    }

    /// Add aliases, which function as *visible* short flag subcommands.
    ///
    /// See [`Command::short_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('b')
    ///                 .visible_short_flag_aliases(['t']))
    ///             .get_matches_from(vec!["myprog", "-t"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_aliases`]: Command::short_flag_aliases()
    #[must_use]
    pub fn visible_short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, true));
        }
        self
    }

    /// Add aliases, which function as *visible* long flag subcommands.
    ///
    /// See [`Command::long_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_aliases(["testing", "testall", "test_all"]))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_aliases`]: Command::long_flag_aliases()
    #[must_use]
    pub fn visible_long_flag_aliases(
        mut self,
        names: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        for s in names {
            self = self.visible_long_flag_alias(s);
        }
        self
    }

    /// Set the placement of this subcommand within the help.
    ///
    /// Subcommands with a lower value will be displayed first in the help message.  Subcommands
    /// with duplicate display orders will be displayed in alphabetical order.
    ///
    /// This is helpful when one would like to emphasize frequently used subcommands, or prioritize
    /// those towards the top of the list.
    ///
    /// **NOTE:** The default is 999 for all subcommands.
    ///
    /// # Examples
    ///
    #[cfg_attr(not(feature = "help"), doc = " ```ignore")]
    #[cfg_attr(feature = "help", doc = " ```")]
    /// # use clap::{Command, };
    /// let m = Command::new("cust-ord")
    ///     .subcommand(Command::new("alpha") // typically subcommands are grouped
    ///                                                // alphabetically by name. Subcommands
    ///                                                // without a display_order have a value of
    ///                                                // 999 and are displayed alphabetically with
    ///                                                // all other 999 subcommands
    ///         .about("Some help and text"))
    ///     .subcommand(Command::new("beta")
    ///         .display_order(1)   // In order to force this subcommand to appear *first*
    ///                             // all we have to do is give it a value lower than 999.
    ///                             // Any other subcommands with a value of 1 will be displayed
    ///                             // alphabetically with this one...then 2 values, then 3, etc.
    ///         .about("I should be first!"))
    ///     .get_matches_from(vec![
    ///         "cust-ord", "--help"
    ///     ]);
    /// ```
    ///
    /// The above example displays the following help message
    ///
    /// ```text
    /// cust-ord
    ///
    /// Usage: cust-ord [OPTIONS]
    ///
    /// Commands:
    ///     beta    I should be first!
    ///     alpha   Some help and text
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[inline]
    #[must_use]
    pub fn display_order(mut self, ord: impl IntoResettable<usize>) -> Self {
        self.disp_ord = ord.into_resettable().into_option();
        self
    }

    /// Specifies that this [`subcommand`] should be hidden from help messages
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(
    ///         Command::new("test").hide(true)
    ///     )
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn hide(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Hidden)
        } else {
            self.unset_setting(AppSettings::Hidden)
        }
    }

    /// If no [`subcommand`] is present at runtime, error and exit gracefully.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_required(true)
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog",
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingSubcommand);
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    pub fn subcommand_required(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandRequired)
        } else {
            self.unset_setting(AppSettings::SubcommandRequired)
        }
    }

    /// Assume unexpected positional arguments are a [`subcommand`].
    ///
    /// Arguments will be stored in the `""` argument in the [`ArgMatches`]
    ///
    /// **NOTE:** Use this setting with caution,
    /// as a truly unexpected argument (i.e. one that is *NOT* an external subcommand)
    /// will **not** cause an error and instead be treated as a potential subcommand.
    /// One should check for such cases manually and inform the user appropriately.
    ///
    /// **NOTE:** A built-in subcommand will be parsed as an external subcommand when escaped with
    /// `--`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    /// [`ArgMatches`]: crate::ArgMatches
    /// [`ErrorKind::UnknownArgument`]: crate::error::ErrorKind::UnknownArgument
    pub fn allow_external_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowExternalSubcommands)
        } else {
            self.unset_setting(AppSettings::AllowExternalSubcommands)
        }
    }

    /// Specifies how to parse external subcommand arguments.
    ///
    /// The default parser is for `OsString`.  This can be used to switch it to `String` or another
    /// type.
    ///
    /// **NOTE:** Setting this requires [`Command::allow_external_subcommands`]
    ///
    /// # Examples
    ///
    #[cfg_attr(not(unix), doc = " ```ignore")]
    #[cfg_attr(unix, doc = " ```")]
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// ```
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .external_subcommand_value_parser(value_parser!(String))
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<String>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn external_subcommand_value_parser(
        mut self,
        parser: impl IntoResettable<super::ValueParser>,
    ) -> Self {
        self.external_value_parser = parser.into_resettable().into_option();
        self
    }

    /// Specifies that use of an argument prevents the use of [`subcommands`].
    ///
    /// By default `clap` allows arguments between subcommands such
    /// as `<cmd> [cmd_args] <subcmd> [subcmd_args] <subsubcmd> [subsubcmd_args]`.
    ///
    /// This setting disables that functionality and says that arguments can
    /// only follow the *final* subcommand. For instance using this setting
    /// makes only the following invocations possible:
    ///
    /// * `<cmd> <subcmd> <subsubcmd> [subsubcmd_args]`
    /// * `<cmd> <subcmd> [subcmd_args]`
    /// * `<cmd> [cmd_args]`
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .args_conflicts_with_subcommands(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn args_conflicts_with_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgsNegateSubcommands)
        } else {
            self.unset_setting(AppSettings::ArgsNegateSubcommands)
        }
    }

    /// Prevent subcommands from being consumed as an arguments value.
    ///
    /// By default, if an option taking multiple values is followed by a subcommand, the
    /// subcommand will be parsed as another value.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   another value
    /// ```
    ///
    /// This setting instructs the parser to stop when encountering a subcommand instead of
    /// greedily consuming arguments.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   subcommand
    /// ```
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let cmd = Command::new("cmd").subcommand(Command::new("sub")).arg(
    ///     Arg::new("arg")
    ///         .long("arg")
    ///         .num_args(1..)
    ///         .action(ArgAction::Set),
    /// );
    ///
    /// let matches = cmd
    ///     .clone()
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3", "sub"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_none());
    ///
    /// let matches = cmd
    ///     .subcommand_precedence_over_arg(true)
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_some());
    /// ```
    pub fn subcommand_precedence_over_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandPrecedenceOverArg)
        } else {
            self.unset_setting(AppSettings::SubcommandPrecedenceOverArg)
        }
    }

    /// Allows [`subcommands`] to override all requirements of the parent command.
    ///
    /// For example, if you had a subcommand or top level application with a required argument
    /// that is only required as long as there is no subcommand present,
    /// using this setting would allow you to set those arguments to [`Arg::required(true)`]
    /// and yet receive no error so long as the user uses a valid subcommand instead.
    ///
    /// **NOTE:** This defaults to false (using subcommand does *not* negate requirements)
    ///
    /// # Examples
    ///
    /// This first example shows that it is an error to not use a required argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog"
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);
    /// # ;
    /// ```
    ///
    /// This next example shows that it is no longer error to not use a required argument if a
    /// valid subcommand is used.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let noerr = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "test"
    ///     ]);
    /// assert!(noerr.is_ok());
    /// # ;
    /// ```
    ///
    /// [`Arg::required(true)`]: crate::Arg::required()
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn subcommand_negates_reqs(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandsNegateReqs)
        } else {
            self.unset_setting(AppSettings::SubcommandsNegateReqs)
        }
    }

    /// Multiple-personality program dispatched on the binary name (`argv[0]`)
    ///
    /// A "multicall" executable is a single executable
    /// that contains a variety of applets,
    /// and decides which applet to run based on the name of the file.
    /// The executable can be called from different names by creating hard links
    /// or symbolic links to it.
    ///
    /// This is desirable for:
    /// - Easy distribution, a single binary that can install hardlinks to access the different
    ///   personalities.
    /// - Minimal binary size by sharing common code (e.g. standard library, clap)
    /// - Custom shells or REPLs where there isn't a single top-level command
    ///
    /// Setting `multicall` will cause
    /// - `argv[0]` to be stripped to the base name and parsed as the first argument, as if
    ///   [`Command::no_binary_name`][Command::no_binary_name] was set.
    /// - Help and errors to report subcommands as if they were the top-level command
    ///
    /// When the subcommand is not present, there are several strategies you may employ, depending
    /// on your needs:
    /// - Let the error percolate up normally
    /// - Print a specialized error message using the
    ///   [`Error::context`][crate::Error::context]
    /// - Print the [help][Command::write_help] but this might be ambiguous
    /// - Disable `multicall` and re-parse it
    /// - Disable `multicall` and re-parse it with a specific subcommand
    ///
    /// When detecting the error condition, the [`ErrorKind`] isn't sufficient as a sub-subcommand
    /// might report the same error.  Enable
    /// [`allow_external_subcommands`][Command::allow_external_subcommands] if you want to specifically
    /// get the unrecognized binary name.
    ///
    /// **NOTE:** Multicall can't be used with [`no_binary_name`] since they interpret
    /// the command name in incompatible ways.
    ///
    /// **NOTE:** The multicall command cannot have arguments.
    ///
    /// **NOTE:** Applets are slightly semantically different from subcommands,
    /// so it's recommended to use [`Command::subcommand_help_heading`] and
    /// [`Command::subcommand_value_name`] to change the descriptive text as above.
    ///
    /// # Examples
    ///
    /// `hostname` is an example of a multicall executable.
    /// Both `hostname` and `dnsdomainname` are provided by the same executable
    /// and which behaviour to use is based on the executable file name.
    ///
    /// This is desirable when the executable has a primary purpose
    /// but there is related functionality that would be convenient to provide
    /// and implement it to be in the same executable.
    ///
    /// The name of the cmd is essentially unused
    /// and may be the same as the name of a subcommand.
    ///
    /// The names of the immediate subcommands of the Command
    /// are matched against the basename of the first argument,
    /// which is conventionally the path of the executable.
    ///
    /// This does not allow the subcommand to be passed as the first non-path argument.
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("hostname")
    ///     .multicall(true)
    ///     .subcommand(Command::new("hostname"))
    ///     .subcommand(Command::new("dnsdomainname"));
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/hostname", "dnsdomainname"]);
    /// assert!(m.is_err());
    /// assert_eq!(m.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// let m = cmd.get_matches_from(&["/usr/bin/dnsdomainname"]);
    /// assert_eq!(m.subcommand_name(), Some("dnsdomainname"));
    /// ```
    ///
    /// Busybox is another common example of a multicall executable
    /// with a subcommmand for each applet that can be run directly,
    /// e.g. with the `cat` applet being run by running `busybox cat`,
    /// or with `cat` as a link to the `busybox` binary.
    ///
    /// This is desirable when the launcher program has additional options
    /// or it is useful to run the applet without installing a symlink
    /// e.g. to test the applet without installing it
    /// or there may already be a command of that name installed.
    ///
    /// To make an applet usable as both a multicall link and a subcommand
    /// the subcommands must be defined both in the top-level Command
    /// and as subcommands of the "main" applet.
    ///
    /// ```rust
    /// # use clap::Command;
    /// fn applet_commands() -> [Command; 2] {
    ///     [Command::new("true"), Command::new("false")]
    /// }
    /// let mut cmd = Command::new("busybox")
    ///     .multicall(true)
    ///     .subcommand(
    ///         Command::new("busybox")
    ///             .subcommand_value_name("APPLET")
    ///             .subcommand_help_heading("APPLETS")
    ///             .subcommands(applet_commands()),
    ///     )
    ///     .subcommands(applet_commands());
    /// // When called from the executable's canonical name
    /// // its applets can be matched as subcommands.
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/busybox", "true"]).unwrap();
    /// assert_eq!(m.subcommand_name(), Some("busybox"));
    /// assert_eq!(m.subcommand().unwrap().1.subcommand_name(), Some("true"));
    /// // When called from a link named after an applet that applet is matched.
    /// let m = cmd.get_matches_from(&["/usr/bin/true"]);
    /// assert_eq!(m.subcommand_name(), Some("true"));
    /// ```
    ///
    /// [`no_binary_name`]: crate::Command::no_binary_name
    /// [`Command::subcommand_value_name`]: crate::Command::subcommand_value_name
    /// [`Command::subcommand_help_heading`]: crate::Command::subcommand_help_heading
    #[inline]
    pub fn multicall(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Multicall)
        } else {
            self.unset_setting(AppSettings::Multicall)
        }
    }

    /// Sets the value name used for subcommands when printing usage and help.
    ///
    /// By default, this is "COMMAND".
    ///
    /// See also [`Command::subcommand_help_heading`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_value_name`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_value_name("THING")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [THING]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_value_name(mut self, value_name: impl IntoResettable<Str>) -> Self {
        self.subcommand_value_name = value_name.into_resettable().into_option();
        self
    }

    /// Sets the help heading used for subcommands when printing usage and help.
    ///
    /// By default, this is "Commands".
    ///
    /// See also [`Command::subcommand_value_name`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_help_heading`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_help_heading("Things")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Things:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.subcommand_heading = heading.into_resettable().into_option();
        self
    }
}

/// # Reflection
impl Command {
    #[inline]
    #[cfg(feature = "usage")]
    pub(crate) fn get_usage_name(&self) -> Option<&str> {
        self.usage_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_display_name(&self) -> Option<&str> {
        self.display_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_bin_name(&self) -> Option<&str> {
        self.bin_name.as_deref()
    }

    /// Set binary name. Uses `&mut self` instead of `self`.
    pub fn set_bin_name(&mut self, name: impl Into<String>) {
        self.bin_name = Some(name.into());
    }

    /// Get the name of the cmd.
    #[inline]
    pub fn get_name(&self) -> &str {
        self.name.as_str()
    }

    #[inline]
    #[cfg(debug_assertions)]
    pub(crate) fn get_name_str(&self) -> &Str {
        &self.name
    }

    /// Get the version of the cmd.
    #[inline]
    pub fn get_version(&self) -> Option<&str> {
        self.version.as_deref()
    }

    /// Get the long version of the cmd.
    #[inline]
    pub fn get_long_version(&self) -> Option<&str> {
        self.long_version.as_deref()
    }

    /// Get the authors of the cmd.
    #[inline]
    pub fn get_author(&self) -> Option<&str> {
        self.author.as_deref()
    }

    /// Get the short flag of the subcommand.
    #[inline]
    pub fn get_short_flag(&self) -> Option<char> {
        self.short_flag
    }

    /// Get the long flag of the subcommand.
    #[inline]
    pub fn get_long_flag(&self) -> Option<&str> {
        self.long_flag.as_deref()
    }

    /// Get the help message specified via [`Command::about`].
    ///
    /// [`Command::about`]: Command::about()
    #[inline]
    pub fn get_about(&self) -> Option<&StyledStr> {
        self.about.as_ref()
    }

    /// Get the help message specified via [`Command::long_about`].
    ///
    /// [`Command::long_about`]: Command::long_about()
    #[inline]
    pub fn get_long_about(&self) -> Option<&StyledStr> {
        self.long_about.as_ref()
    }

    /// Get the custom section heading specified via [`Command::next_help_heading`].
    ///
    /// [`Command::help_heading`]: Command::help_heading()
    #[inline]
    pub fn get_next_help_heading(&self) -> Option<&str> {
        self.current_help_heading.as_deref()
    }

    /// Iterate through the *visible* aliases for this subcommand.
    #[inline]
    pub fn get_visible_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the *visible* short aliases for this subcommand.
    #[inline]
    pub fn get_visible_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0)
    }

    /// Iterate through the *visible* long aliases for this subcommand.
    #[inline]
    pub fn get_visible_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases.iter().map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the short aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases.iter().map(|a| a.0)
    }

    /// Iterate through the set of *all* the long aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases.iter().map(|a| a.0.as_str())
    }

    #[inline]
    pub(crate) fn is_set(&self, s: AppSettings) -> bool {
        self.settings.is_set(s) || self.g_settings.is_set(s)
    }

    /// Should we color the output?
    pub fn get_color(&self) -> ColorChoice {
        debug!("Command::color: Color setting...");

        if cfg!(feature = "color") {
            if self.is_set(AppSettings::ColorNever) {
                debug!("Never");
                ColorChoice::Never
            } else if self.is_set(AppSettings::ColorAlways) {
                debug!("Always");
                ColorChoice::Always
            } else {
                debug!("Auto");
                ColorChoice::Auto
            }
        } else {
            ColorChoice::Never
        }
    }

    /// Iterate through the set of subcommands, getting a reference to each.
    #[inline]
    pub fn get_subcommands(&self) -> impl Iterator<Item = &Command> {
        self.subcommands.iter()
    }

    /// Iterate through the set of subcommands, getting a mutable reference to each.
    #[inline]
    pub fn get_subcommands_mut(&mut self) -> impl Iterator<Item = &mut Command> {
        self.subcommands.iter_mut()
    }

    /// Returns `true` if this `Command` has subcommands.
    #[inline]
    pub fn has_subcommands(&self) -> bool {
        !self.subcommands.is_empty()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_subcommand_help_heading(&self) -> Option<&str> {
        self.subcommand_heading.as_deref()
    }

    /// Returns the subcommand value name.
    #[inline]
    pub fn get_subcommand_value_name(&self) -> Option<&str> {
        self.subcommand_value_name.as_deref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_help(&self) -> Option<&StyledStr> {
        self.before_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_long_help(&self) -> Option<&StyledStr> {
        self.before_long_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_help(&self) -> Option<&StyledStr> {
        self.after_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_long_help(&self) -> Option<&StyledStr> {
        self.after_long_help.as_ref()
    }

    /// Find subcommand such that its name or one of aliases equals `name`.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand(&self, name: impl AsRef<std::ffi::OsStr>) -> Option<&Command> {
        let name = name.as_ref();
        self.get_subcommands().find(|s| s.aliases_to(name))
    }

    /// Find subcommand such that its name or one of aliases equals `name`, returning
    /// a mutable reference to the subcommand.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand_mut(
        &mut self,
        name: impl AsRef<std::ffi::OsStr>,
    ) -> Option<&mut Command> {
        let name = name.as_ref();
        self.get_subcommands_mut().find(|s| s.aliases_to(name))
    }

    /// Iterate through the set of groups.
    #[inline]
    pub fn get_groups(&self) -> impl Iterator<Item = &ArgGroup> {
        self.groups.iter()
    }

    /// Iterate through the set of arguments.
    #[inline]
    pub fn get_arguments(&self) -> impl Iterator<Item = &Arg> {
        self.args.args()
    }

    /// Iterate through the *positionals* arguments.
    #[inline]
    pub fn get_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| a.is_positional())
    }

    /// Iterate through the *options*.
    pub fn get_opts(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments()
            .filter(|a| a.is_takes_value_set() && !a.is_positional())
    }

    /// Get a list of all arguments the given argument conflicts with.
    ///
    /// If the provided argument is declared as global, the conflicts will be determined
    /// based on the propagation rules of global arguments.
    ///
    /// ### Panics
    ///
    /// If the given arg contains a conflict with an argument that is unknown to
    /// this `Command`.
    pub fn get_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        if arg.is_global_set() {
            self.get_global_arg_conflicts_with(arg)
        } else {
            let mut result = Vec::new();
            for id in arg.blacklist.iter() {
                if let Some(arg) = self.find(id) {
                    result.push(arg);
                } else if let Some(group) = self.find_group(id) {
                    result.extend(
                        self.unroll_args_in_group(&group.id)
                            .iter()
                            .map(|id| self.find(id).expect(INTERNAL_ERROR_MSG)),
                    );
                } else {
                    panic!("Command::get_arg_conflicts_with: The passed arg conflicts with an arg unknown to the cmd");
                }
            }
            result
        }
    }

    // Get a unique list of all arguments of all commands and continuous subcommands the given argument conflicts with.
    //
    // This behavior follows the propagation rules of global arguments.
    // It is useful for finding conflicts for arguments declared as global.
    //
    // ### Panics
    //
    // If the given arg contains a conflict with an argument that is unknown to
    // this `Command`.
    fn get_global_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        arg.blacklist
            .iter()
            .map(|id| {
                self.args
                    .args()
                    .chain(
                        self.get_subcommands_containing(arg)
                            .iter()
                            .flat_map(|x| x.args.args()),
                    )
                    .find(|arg| arg.get_id() == id)
                    .expect(
                        "Command::get_arg_conflicts_with: \
                    The passed arg conflicts with an arg unknown to the cmd",
                    )
            })
            .collect()
    }

    // Get a list of subcommands which contain the provided Argument
    //
    // This command will only include subcommands in its list for which the subcommands
    // parent also contains the Argument.
    //
    // This search follows the propagation rules of global arguments.
    // It is useful to finding subcommands, that have inherited a global argument.
    //
    // **NOTE:** In this case only Sucommand_1 will be included
    //   Subcommand_1 (contains Arg)
    //     Subcommand_1.1 (doesn't contain Arg)
    //       Subcommand_1.1.1 (contains Arg)
    //
    fn get_subcommands_containing(&self, arg: &Arg) -> Vec<&Self> {
        let mut vec = std::vec::Vec::new();
        for idx in 0..self.subcommands.len() {
            if self.subcommands[idx]
                .args
                .args()
                .any(|ar| ar.get_id() == arg.get_id())
            {
                vec.push(&self.subcommands[idx]);
                vec.append(&mut self.subcommands[idx].get_subcommands_containing(arg));
            }
        }
        vec
    }

    /// Report whether [`Command::no_binary_name`] is set
    pub fn is_no_binary_name_set(&self) -> bool {
        self.is_set(AppSettings::NoBinaryName)
    }

    /// Report whether [`Command::ignore_errors`] is set
    pub(crate) fn is_ignore_errors_set(&self) -> bool {
        self.is_set(AppSettings::IgnoreErrors)
    }

    /// Report whether [`Command::dont_delimit_trailing_values`] is set
    pub fn is_dont_delimit_trailing_values_set(&self) -> bool {
        self.is_set(AppSettings::DontDelimitTrailingValues)
    }

    /// Report whether [`Command::disable_version_flag`] is set
    pub fn is_disable_version_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableVersionFlag)
            || (self.version.is_none() && self.long_version.is_none())
    }

    /// Report whether [`Command::propagate_version`] is set
    pub fn is_propagate_version_set(&self) -> bool {
        self.is_set(AppSettings::PropagateVersion)
    }

    /// Report whether [`Command::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(AppSettings::NextLineHelp)
    }

    /// Report whether [`Command::disable_help_flag`] is set
    pub fn is_disable_help_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpFlag)
    }

    /// Report whether [`Command::disable_help_subcommand`] is set
    pub fn is_disable_help_subcommand_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpSubcommand)
    }

    /// Report whether [`Command::disable_colored_help`] is set
    pub fn is_disable_colored_help_set(&self) -> bool {
        self.is_set(AppSettings::DisableColoredHelp)
    }

    /// Report whether [`Command::help_expected`] is set
    #[cfg(debug_assertions)]
    pub(crate) fn is_help_expected_set(&self) -> bool {
        self.is_set(AppSettings::HelpExpected)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn is_dont_collapse_args_in_usage_set(&self) -> bool {
        true
    }

    /// Report whether [`Command::infer_long_args`] is set
    pub(crate) fn is_infer_long_args_set(&self) -> bool {
        self.is_set(AppSettings::InferLongArgs)
    }

    /// Report whether [`Command::infer_subcommands`] is set
    pub(crate) fn is_infer_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::InferSubcommands)
    }

    /// Report whether [`Command::arg_required_else_help`] is set
    pub fn is_arg_required_else_help_set(&self) -> bool {
        self.is_set(AppSettings::ArgRequiredElseHelp)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_hyphen_values_set`"
        )
    )]
    pub(crate) fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(AppSettings::AllowHyphenValues)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_negative_numbers_set`"
        )
    )]
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(AppSettings::AllowNegativeNumbers)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::is_trailing_var_arg_set`")
    )]
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(AppSettings::TrailingVarArg)
    }

    /// Report whether [`Command::allow_missing_positional`] is set
    pub fn is_allow_missing_positional_set(&self) -> bool {
        self.is_set(AppSettings::AllowMissingPositional)
    }

    /// Report whether [`Command::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(AppSettings::Hidden)
    }

    /// Report whether [`Command::subcommand_required`] is set
    pub fn is_subcommand_required_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandRequired)
    }

    /// Report whether [`Command::allow_external_subcommands`] is set
    pub fn is_allow_external_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::AllowExternalSubcommands)
    }

    /// Configured parser for values passed to an external subcommand
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .external_subcommand_value_parser(clap::value_parser!(String));
    /// let value_parser = cmd.get_external_subcommand_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_external_subcommand_value_parser(&self) -> Option<&super::ValueParser> {
        if !self.is_allow_external_subcommands_set() {
            None
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::os_string();
            Some(self.external_value_parser.as_ref().unwrap_or(&DEFAULT))
        }
    }

    /// Report whether [`Command::args_conflicts_with_subcommands`] is set
    pub fn is_args_conflicts_with_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::ArgsNegateSubcommands)
    }

    #[doc(hidden)]
    pub fn is_args_override_self(&self) -> bool {
        self.is_set(AppSettings::AllArgsOverrideSelf)
    }

    /// Report whether [`Command::subcommand_precedence_over_arg`] is set
    pub fn is_subcommand_precedence_over_arg_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandPrecedenceOverArg)
    }

    /// Report whether [`Command::subcommand_negates_reqs`] is set
    pub fn is_subcommand_negates_reqs_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandsNegateReqs)
    }

    /// Report whether [`Command::multicall`] is set
    pub fn is_multicall_set(&self) -> bool {
        self.is_set(AppSettings::Multicall)
    }
}

// Internally used only
impl Command {
    pub(crate) fn get_override_usage(&self) -> Option<&StyledStr> {
        self.usage_str.as_ref()
    }

    pub(crate) fn get_override_help(&self) -> Option<&StyledStr> {
        self.help_str.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_help_template(&self) -> Option<&StyledStr> {
        self.template.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_term_width(&self) -> Option<usize> {
        self.term_w
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_max_term_width(&self) -> Option<usize> {
        self.max_w
    }

    pub(crate) fn get_replacement(&self, key: &str) -> Option<&[Str]> {
        self.replacers.get(key).map(|v| v.as_slice())
    }

    pub(crate) fn get_keymap(&self) -> &MKeyMap {
        &self.args
    }

    fn get_used_global_args(&self, matches: &ArgMatches, global_arg_vec: &mut Vec<Id>) {
        global_arg_vec.extend(
            self.args
                .args()
                .filter(|a| a.is_global_set())
                .map(|ga| ga.id.clone()),
        );
        if let Some((id, matches)) = matches.subcommand() {
            if let Some(used_sub) = self.find_subcommand(id) {
                used_sub.get_used_global_args(matches, global_arg_vec);
            }
        }
    }

    fn _do_parse(
        &mut self,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<ArgMatches> {
        debug!("Command::_do_parse");

        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing in case we run into a subcommand
        self._build_self(false);

        let mut matcher = ArgMatcher::new(self);

        // do the real parsing
        let mut parser = Parser::new(self);
        if let Err(error) = parser.get_matches_with(&mut matcher, raw_args, args_cursor) {
            if self.is_set(AppSettings::IgnoreErrors) {
                debug!("Command::_do_parse: ignoring error: {}", error);
            } else {
                return Err(error);
            }
        }

        let mut global_arg_vec = Default::default();
        self.get_used_global_args(&matcher, &mut global_arg_vec);

        matcher.propagate_globals(&global_arg_vec);

        Ok(matcher.into_inner())
    }

    /// Prepare for introspecting on all included [`Command`]s
    ///
    /// Call this on the top-level [`Command`] when done building and before reading state for
    /// cases like completions, custom help output, etc.
    pub fn build(&mut self) {
        self._build_recursive(true);
        self._build_bin_names_internal();
    }

    pub(crate) fn _build_recursive(&mut self, expand_help_tree: bool) {
        self._build_self(expand_help_tree);
        for subcmd in self.get_subcommands_mut() {
            subcmd._build_recursive(expand_help_tree);
        }
    }

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

    pub(crate) fn _build_subcommand(&mut self, name: &str) -> Option<&mut Self> {
        use std::fmt::Write;

        let mut mid_string = String::from(" ");
        #[cfg(feature = "usage")]
        if !self.is_subcommand_negates_reqs_set() && !self.is_args_conflicts_with_subcommands_set()
        {
            let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

            for s in &reqs {
                mid_string.push_str(&s.to_string());
                mid_string.push(' ');
            }
        }
        let is_multicall_set = self.is_multicall_set();

        let sc = some!(self.subcommands.iter_mut().find(|s| s.name == name));

        // Display subcommand name, short and long in usage
        let mut sc_names = String::new();
        sc_names.push_str(sc.name.as_str());
        let mut flag_subcmd = false;
        if let Some(l) = sc.get_long_flag() {
            write!(sc_names, "|--{}", l).unwrap();
            flag_subcmd = true;
        }
        if let Some(s) = sc.get_short_flag() {
            write!(sc_names, "|-{}", s).unwrap();
            flag_subcmd = true;
        }

        if flag_subcmd {
            sc_names = format!("{{{}}}", sc_names);
        }

        let usage_name = self
            .bin_name
            .as_ref()
            .map(|bin_name| format!("{}{}{}", bin_name, mid_string, sc_names))
            .unwrap_or(sc_names);
        sc.usage_name = Some(usage_name);

        // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
        // a space
        let bin_name = format!(
            "{}{}{}",
            self.bin_name.as_deref().unwrap_or_default(),
            if self.bin_name.is_some() { " " } else { "" },
            &*sc.name
        );
        debug!(
            "Command::_build_subcommand Setting bin_name of {} to {:?}",
            sc.name, bin_name
        );
        sc.bin_name = Some(bin_name);

        if sc.display_name.is_none() {
            let self_display_name = if is_multicall_set {
                self.display_name.as_deref().unwrap_or("")
            } else {
                self.display_name.as_deref().unwrap_or(&self.name)
            };
            let display_name = format!(
                "{}{}{}",
                self_display_name,
                if !self_display_name.is_empty() {
                    "-"
                } else {
                    ""
                },
                &*sc.name
            );
            debug!(
                "Command::_build_subcommand Setting display_name of {} to {:?}",
                sc.name, display_name
            );
            sc.display_name = Some(display_name);
        }

        // Ensure all args are built and ready to parse
        sc._build_self(false);

        Some(sc)
    }

    fn _build_bin_names_internal(&mut self) {
        debug!("Command::_build_bin_names");

        if !self.is_set(AppSettings::BinNameBuilt) {
            let mut mid_string = String::from(" ");
            #[cfg(feature = "usage")]
            if !self.is_subcommand_negates_reqs_set()
                && !self.is_args_conflicts_with_subcommands_set()
            {
                let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

                for s in &reqs {
                    mid_string.push_str(&s.to_string());
                    mid_string.push(' ');
                }
            }
            let is_multicall_set = self.is_multicall_set();

            let self_bin_name = if is_multicall_set {
                self.bin_name.as_deref().unwrap_or("")
            } else {
                self.bin_name.as_deref().unwrap_or(&self.name)
            }
            .to_owned();

            for mut sc in &mut self.subcommands {
                debug!("Command::_build_bin_names:iter: bin_name set...");

                if sc.usage_name.is_none() {
                    use std::fmt::Write;
                    // Display subcommand name, short and long in usage
                    let mut sc_names = String::new();
                    sc_names.push_str(sc.name.as_str());
                    let mut flag_subcmd = false;
                    if let Some(l) = sc.get_long_flag() {
                        write!(sc_names, "|--{}", l).unwrap();
                        flag_subcmd = true;
                    }
                    if let Some(s) = sc.get_short_flag() {
                        write!(sc_names, "|-{}", s).unwrap();
                        flag_subcmd = true;
                    }

                    if flag_subcmd {
                        sc_names = format!("{{{}}}", sc_names);
                    }

                    let usage_name = format!("{}{}{}", self_bin_name, mid_string, sc_names);
                    debug!(
                        "Command::_build_bin_names:iter: Setting usage_name of {} to {:?}",
                        sc.name, usage_name
                    );
                    sc.usage_name = Some(usage_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing usage_name of {} ({:?})",
                        sc.name, sc.usage_name
                    );
                }

                if sc.bin_name.is_none() {
                    let bin_name = format!(
                        "{}{}{}",
                        self_bin_name,
                        if !self_bin_name.is_empty() { " " } else { "" },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting bin_name of {} to {:?}",
                        sc.name, bin_name
                    );
                    sc.bin_name = Some(bin_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing bin_name of {} ({:?})",
                        sc.name, sc.bin_name
                    );
                }

                if sc.display_name.is_none() {
                    let self_display_name = if is_multicall_set {
                        self.display_name.as_deref().unwrap_or("")
                    } else {
                        self.display_name.as_deref().unwrap_or(&self.name)
                    };
                    let display_name = format!(
                        "{}{}{}",
                        self_display_name,
                        if !self_display_name.is_empty() {
                            "-"
                        } else {
                            ""
                        },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting display_name of {} to {:?}",
                        sc.name, display_name
                    );
                    sc.display_name = Some(display_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing display_name of {} ({:?})",
                        sc.name, sc.display_name
                    );
                }

                sc._build_bin_names_internal();
            }
            self.set(AppSettings::BinNameBuilt);
        } else {
            debug!("Command::_build_bin_names: already built");
        }
    }

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

    /// Propagate settings
    pub(crate) fn _propagate(&mut self) {
        debug!("Command::_propagate:{}", self.name);
        let mut subcommands = std::mem::take(&mut self.subcommands);
        for sc in &mut subcommands {
            self._propagate_subcommand(sc);
        }
        self.subcommands = subcommands;
    }

    fn _propagate_subcommand(&self, sc: &mut Self) {
        // We have to create a new scope in order to tell rustc the borrow of `sc` is
        // done and to recursively call this method
        {
            if self.settings.is_set(AppSettings::PropagateVersion) {
                if let Some(version) = self.version.as_ref() {
                    sc.version.get_or_insert_with(|| version.clone());
                }
                if let Some(long_version) = self.long_version.as_ref() {
                    sc.long_version.get_or_insert_with(|| long_version.clone());
                }
            }

            sc.settings = sc.settings | self.g_settings;
            sc.g_settings = sc.g_settings | self.g_settings;
            sc.term_w = self.term_w;
            sc.max_w = self.max_w;
        }
    }

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

    pub(crate) fn _render_version(&self, use_long: bool) -> String {
        debug!("Command::_render_version");

        let ver = if use_long {
            self.long_version
                .as_deref()
                .or(self.version.as_deref())
                .unwrap_or_default()
        } else {
            self.version
                .as_deref()
                .or(self.long_version.as_deref())
                .unwrap_or_default()
        };
        let display_name = self.get_display_name().unwrap_or_else(|| self.get_name());
        format!("{} {}\n", display_name, ver)
    }

    pub(crate) fn format_group(&self, g: &Id) -> StyledStr {
        let g_string = self
            .unroll_args_in_group(g)
            .iter()
            .filter_map(|x| self.find(x))
            .map(|x| {
                if x.is_positional() {
                    // Print val_name for positional arguments. e.g. <file_name>
                    x.name_no_brackets()
                } else {
                    // Print usage string for flags arguments, e.g. <--help>
                    x.to_string()
                }
            })
            .collect::<Vec<_>>()
            .join("|");
        let mut styled = StyledStr::new();
        styled.none("<");
        styled.none(g_string);
        styled.none(">");
        styled
    }
}

/// A workaround:
/// <https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999>
pub(crate) trait Captures<'a> {}
impl<'a, T> Captures<'a> for T {}

// Internal Query Methods
impl Command {
    /// Iterate through the *flags* & *options* arguments.
    #[cfg(any(feature = "usage", feature = "help"))]
    pub(crate) fn get_non_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| !a.is_positional())
    }

src/output/help_template.rs (line 515)

    fn align_to_about(&mut self, arg: &Arg, next_line_help: bool, longest: usize) {
        debug!(
            "HelpTemplate::align_to_about: arg={}, next_line_help={}, longest={}",
            arg.get_id(),
            next_line_help,
            longest
        );
        if self.use_long || next_line_help {
            // long help prints messages on the next line so it doesn't need to align text
            debug!("HelpTemplate::align_to_about: printing long help so skip alignment");
        } else if !arg.is_positional() {
            let self_len = display_width(&arg.to_string());
            // Since we're writing spaces from the tab point we first need to know if we
            // had a long and short, or just short
            let padding = if arg.get_long().is_some() {
                // Only account 4 after the val
                TAB_WIDTH
            } else {
                // Only account for ', --' + 4 after the val
                TAB_WIDTH + 4
            };
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=false arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        } else {
            let self_len = display_width(&arg.to_string());
            let padding = TAB_WIDTH;
            let spcs = longest + padding - self_len;
            debug!(
                "HelpTemplate::align_to_about: positional=true arg_len={}, spaces={}",
                self_len, spcs
            );

            self.spaces(spcs);
        }
    }

    /// Writes argument's help to the wrapped stream.
    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

src/builder/arg.rs (line 4062)

    pub(crate) fn _build(&mut self) {
        if self.action.is_none() {
            if self.num_vals == Some(ValueRange::EMPTY) {
                let action = super::ArgAction::SetTrue;
                self.action = Some(action);
            } else {
                let action =
                    if self.is_positional() && self.num_vals.unwrap_or_default().is_unbounded() {
                        // Allow collecting arguments interleaved with flags
                        //
                        // Bounded values are probably a group and the user should explicitly opt-in to
                        // Append
                        super::ArgAction::Append
                    } else {
                        super::ArgAction::Set
                    };
                self.action = Some(action);
            }
        }
        if let Some(action) = self.action.as_ref() {
            if let Some(default_value) = action.default_value() {
                if self.default_vals.is_empty() {
                    self.default_vals = vec![default_value.into()];
                }
            }
            if let Some(default_value) = action.default_missing_value() {
                if self.default_missing_vals.is_empty() {
                    self.default_missing_vals = vec![default_value.into()];
                }
            }
        }

        if self.value_parser.is_none() {
            if let Some(default) = self.action.as_ref().and_then(|a| a.default_value_parser()) {
                self.value_parser = Some(default);
            } else {
                self.value_parser = Some(super::ValueParser::string());
            }
        }

        let val_names_len = self.val_names.len();
        if val_names_len > 1 {
            self.num_vals.get_or_insert(val_names_len.into());
        } else {
            let nargs = if self.get_action().takes_values() {
                ValueRange::SINGLE
            } else {
                ValueRange::EMPTY
            };
            self.num_vals.get_or_insert(nargs);
        }
    }

    // Used for positionals when printing
    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

    /// Write the values such as <name1> <name2>
    fn render_arg_val(&self, required: bool) -> String {
        let mut rendered = String::new();

        let num_vals = self.get_num_args().unwrap_or_else(|| 1.into());

        let mut val_names = if self.val_names.is_empty() {
            vec![self.id.as_internal_str().to_owned()]
        } else {
            self.val_names.clone()
        };
        if val_names.len() == 1 {
            let min = num_vals.min_values().max(1);
            let val_name = val_names.pop().unwrap();
            val_names = vec![val_name; min];
        }

        debug_assert!(self.is_takes_value_set());
        for (n, val_name) in val_names.iter().enumerate() {
            let arg_name = if self.is_positional() && (num_vals.min_values() == 0 || !required) {
                format!("[{}]", val_name)
            } else {
                format!("<{}>", val_name)
            };

            if n != 0 {
                rendered.push(' ');
            }
            rendered.push_str(&arg_name);
        }

        let mut extra_values = false;
        extra_values |= val_names.len() < num_vals.max_values();
        if self.is_positional() && matches!(*self.get_action(), ArgAction::Append) {
            extra_values = true;
        }
        if extra_values {
            rendered.push_str("...");
        }

        rendered
    }

src/builder/debug_asserts.rs (line 136)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn is_required_set(&self) -> bool

Reports whether Arg::required is set

Examples found in repository

src/builder/command.rs (line 4467)

    pub(crate) fn required_graph(&self) -> ChildGraph<Id> {
        let mut reqs = ChildGraph::with_capacity(5);
        for a in self.args.args().filter(|a| a.is_required_set()) {
            reqs.insert(a.get_id().clone());
        }
        for group in &self.groups {
            if group.required {
                let idx = reqs.insert(group.id.clone());
                for a in &group.requires {
                    reqs.insert_child(idx, a.clone());
                }
            }
        }

        reqs
    }

src/builder/arg.rs (line 4169)

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

src/output/usage.rs (line 169)

    fn needs_options_tag(&self) -> bool {
        debug!("Usage::needs_options_tag");
        'outer: for f in self.cmd.get_non_positionals() {
            debug!("Usage::needs_options_tag:iter: f={}", f.get_id());

            // Don't print `[OPTIONS]` just for help or version
            if f.get_long() == Some("help") || f.get_long() == Some("version") {
                debug!("Usage::needs_options_tag:iter Option is built-in");
                continue;
            }

            if f.is_hide_set() {
                debug!("Usage::needs_options_tag:iter Option is hidden");
                continue;
            }
            if f.is_required_set() {
                debug!("Usage::needs_options_tag:iter Option is required");
                continue;
            }
            for grp_s in self.cmd.groups_for_arg(f.get_id()) {
                debug!("Usage::needs_options_tag:iter:iter: grp_s={:?}", grp_s);
                if self.cmd.get_groups().any(|g| g.id == grp_s && g.required) {
                    debug!("Usage::needs_options_tag:iter:iter: Group is required");
                    continue 'outer;
                }
            }

            debug!("Usage::needs_options_tag:iter: [OPTIONS] required");
            return true;
        }

        debug!("Usage::needs_options_tag: [OPTIONS] not required");
        false
    }

src/builder/debug_asserts.rs (line 163)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

pub fn is_allow_hyphen_values_set(&self) -> bool

Report whether Arg::allow_hyphen_values is set

Examples found in repository

src/parser/parser.rs (line 122)

    pub(crate) fn get_matches_with(
        &mut self,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        mut args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<()> {
        debug!("Parser::get_matches_with");
        // Verify all positional assertions pass

        let mut subcmd_name: Option<String> = None;
        let mut keep_state = false;
        let mut parse_state = ParseState::ValuesDone;
        let mut pos_counter = 1;

        // Already met any valid arg(then we shouldn't expect subcommands after it).
        let mut valid_arg_found = false;
        // If the user already passed '--'. Meaning only positional args follow.
        let mut trailing_values = false;

        // Count of positional args
        let positional_count = self
            .cmd
            .get_keymap()
            .keys()
            .filter(|x| x.is_position())
            .count();
        // If any arg sets .last(true)
        let contains_last = self.cmd.get_arguments().any(|x| x.is_last_set());

        while let Some(arg_os) = raw_args.next(&mut args_cursor) {
            // Recover the replaced items if any.
            if let Some(replaced_items) = arg_os
                .to_value()
                .ok()
                .and_then(|a| self.cmd.get_replacement(a))
            {
                debug!(
                    "Parser::get_matches_with: found replacer: {:?}, target: {:?}",
                    arg_os, replaced_items
                );
                raw_args.insert(&args_cursor, replaced_items);
                continue;
            }

            debug!(
                "Parser::get_matches_with: Begin parsing '{:?}' ({:?})",
                arg_os.to_value_os(),
                arg_os.to_value_os().as_raw_bytes()
            );

            // Has the user already passed '--'? Meaning only positional args follow
            if !trailing_values {
                if self.cmd.is_subcommand_precedence_over_arg_set()
                    || !matches!(parse_state, ParseState::Opt(_) | ParseState::Pos(_))
                {
                    // Does the arg match a subcommand name, or any of its aliases (if defined)
                    let sc_name = self.possible_subcommand(arg_os.to_value(), valid_arg_found);
                    debug!("Parser::get_matches_with: sc={:?}", sc_name);
                    if let Some(sc_name) = sc_name {
                        if sc_name == "help" && !self.cmd.is_disable_help_subcommand_set() {
                            ok!(self.parse_help_subcommand(raw_args.remaining(&mut args_cursor)));
                            unreachable!("`parse_help_subcommand` always errors");
                        } else {
                            subcmd_name = Some(sc_name.to_owned());
                        }
                        break;
                    }
                }

                if arg_os.is_escape() {
                    if matches!(&parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
                        self.cmd[opt].is_allow_hyphen_values_set())
                    {
                        // ParseResult::MaybeHyphenValue, do nothing
                    } else {
                        debug!("Parser::get_matches_with: setting TrailingVals=true");
                        trailing_values = true;
                        matcher.start_trailing();
                        continue;
                    }
                } else if let Some((long_arg, long_value)) = arg_os.to_long() {
                    let parse_result = ok!(self.parse_long_arg(
                        matcher,
                        long_arg,
                        long_value,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    debug!(
                        "Parser::get_matches_with: After parse_long_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            unreachable!("`to_long` always has the flag specified")
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            debug!(
                                "Parser::get_matches_with: FlagSubCommand found in long arg {:?}",
                                &name
                            );
                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            let remaining_args: Vec<_> =
                                raw_args.remaining(&mut args_cursor).collect();
                            return Err(self.did_you_mean_error(
                                &arg,
                                matcher,
                                &remaining_args,
                                trailing_values,
                            ));
                        }
                        ParseResult::UnneededAttachedValue { rest, used, arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::too_many_values(
                                self.cmd,
                                rest,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&used),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::AttachedValueNotConsumed => {
                            unreachable!()
                        }
                    }
                } else if let Some(short_arg) = arg_os.to_short() {
                    // Arg looks like a short flag, and not a possible number

                    // Try to parse short args like normal, if allow_hyphen_values or
                    // AllowNegativeNumbers is set, parse_short_arg will *not* throw
                    // an error, and instead return Ok(None)
                    let parse_result = ok!(self.parse_short_arg(
                        matcher,
                        short_arg,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    // If it's None, we then check if one of those two AppSettings was set
                    debug!(
                        "Parser::get_matches_with: After parse_short_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            // Is a single dash `-`, try positional.
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            // If there are more short flags to be processed, we should keep the state, and later
                            // revisit the current group of short flags skipping the subcommand.
                            keep_state = self
                                .flag_subcmd_at
                                .map(|at| {
                                    raw_args
                                        .seek(&mut args_cursor, clap_lex::SeekFrom::Current(-1));
                                    // Since we are now saving the current state, the number of flags to skip during state recovery should
                                    // be the current index (`cur_idx`) minus ONE UNIT TO THE LEFT of the starting position.
                                    self.flag_subcmd_skip = self.cur_idx.get() - at + 1;
                                })
                                .is_some();

                            debug!(
                                "Parser::get_matches_with:FlagSubCommandShort: subcmd_name={}, keep_state={}, flag_subcmd_skip={}",
                                name,
                                keep_state,
                                self.flag_subcmd_skip
                            );

                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            // We already know it looks like a flag
                            let suggested_trailing_arg =
                                !trailing_values && self.cmd.has_positionals();
                            return Err(ClapError::unknown_argument(
                                self.cmd,
                                arg,
                                None,
                                suggested_trailing_arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::UnneededAttachedValue { .. }
                        | ParseResult::AttachedValueNotConsumed => unreachable!(),
                    }
                }

                if let ParseState::Opt(id) = &parse_state {
                    // Assume this is a value of a previous arg.

                    // get the option so we can check the settings
                    let arg = &self.cmd[id];
                    let parse_result = if let Some(parse_result) =
                        self.check_terminator(arg, arg_os.to_value_os())
                    {
                        parse_result
                    } else {
                        let trailing_values = false;
                        let arg_values = matcher.pending_values_mut(id, None, trailing_values);
                        arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                        if matcher.needs_more_vals(arg) {
                            ParseResult::Opt(arg.get_id().clone())
                        } else {
                            ParseResult::ValuesDone
                        }
                    };
                    parse_state = match parse_result {
                        ParseResult::Opt(id) => ParseState::Opt(id),
                        ParseResult::ValuesDone => ParseState::ValuesDone,
                        _ => unreachable!(),
                    };
                    // get the next value from the iterator
                    continue;
                }
            }

            // Correct pos_counter.
            pos_counter = {
                let is_second_to_last = pos_counter + 1 == positional_count;

                // The last positional argument, or second to last positional
                // argument may be set to .multiple_values(true) or `.multiple_occurrences(true)`
                let low_index_mults = is_second_to_last
                    && self.cmd.get_positionals().any(|a| {
                        a.is_multiple() && (positional_count != a.get_index().unwrap_or(0))
                    })
                    && self
                        .cmd
                        .get_positionals()
                        .last()
                        .map_or(false, |p_name| !p_name.is_last_set());

                let missing_pos = self.cmd.is_allow_missing_positional_set()
                    && is_second_to_last
                    && !trailing_values;

                debug!(
                    "Parser::get_matches_with: Positional counter...{}",
                    pos_counter
                );
                debug!(
                    "Parser::get_matches_with: Low index multiples...{:?}",
                    low_index_mults
                );

                if low_index_mults || missing_pos {
                    let skip_current = if let Some(n) = raw_args.peek(&args_cursor) {
                        if let Some(arg) = self
                            .cmd
                            .get_positionals()
                            .find(|a| a.get_index() == Some(pos_counter))
                        {
                            // If next value looks like a new_arg or it's a
                            // subcommand, skip positional argument under current
                            // pos_counter(which means current value cannot be a
                            // positional argument with a value next to it), assume
                            // current value matches the next arg.
                            self.is_new_arg(&n, arg)
                                || self
                                    .possible_subcommand(n.to_value(), valid_arg_found)
                                    .is_some()
                        } else {
                            true
                        }
                    } else {
                        true
                    };

                    if skip_current {
                        debug!("Parser::get_matches_with: Bumping the positional counter...");
                        pos_counter + 1
                    } else {
                        pos_counter
                    }
                } else if trailing_values
                    && (self.cmd.is_allow_missing_positional_set() || contains_last)
                {
                    // Came to -- and one positional has .last(true) set, so we go immediately
                    // to the last (highest index) positional
                    debug!("Parser::get_matches_with: .last(true) and --, setting last pos");
                    positional_count
                } else {
                    pos_counter
                }
            };

            if let Some(arg) = self.cmd.get_keymap().get(&pos_counter) {
                if arg.is_last_set() && !trailing_values {
                    let _ = self.resolve_pending(matcher);
                    // Its already considered a positional, we don't need to suggest turning it
                    // into one
                    let suggested_trailing_arg = false;
                    return Err(ClapError::unknown_argument(
                        self.cmd,
                        arg_os.display().to_string(),
                        None,
                        suggested_trailing_arg,
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }

                if arg.is_trailing_var_arg_set() {
                    trailing_values = true;
                }

                if matcher.pending_arg_id() != Some(arg.get_id()) || !arg.is_multiple_values_set() {
                    ok!(self.resolve_pending(matcher));
                }
                if let Some(_parse_result) = self.check_terminator(arg, arg_os.to_value_os()) {
                    debug!(
                        "Parser::get_matches_with: ignoring terminator result {:?}",
                        _parse_result
                    );
                } else {
                    let arg_values = matcher.pending_values_mut(
                        arg.get_id(),
                        Some(Identifier::Index),
                        trailing_values,
                    );
                    arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                }

                // Only increment the positional counter if it doesn't allow multiples
                if !arg.is_multiple() {
                    pos_counter += 1;
                    parse_state = ParseState::ValuesDone;
                } else {
                    parse_state = ParseState::Pos(arg.get_id().clone());
                }
                valid_arg_found = true;
            } else if let Some(external_parser) =
                self.cmd.get_external_subcommand_value_parser().cloned()
            {
                // Get external subcommand name
                let sc_name = match arg_os.to_value() {
                    Ok(s) => s.to_owned(),
                    Err(_) => {
                        let _ = self.resolve_pending(matcher);
                        return Err(ClapError::invalid_utf8(
                            self.cmd,
                            Usage::new(self.cmd).create_usage_with_title(&[]),
                        ));
                    }
                };

                // Collect the external subcommand args
                let mut sc_m = ArgMatcher::new(self.cmd);
                sc_m.start_occurrence_of_external(self.cmd);

                for raw_val in raw_args.remaining(&mut args_cursor) {
                    let val = ok!(external_parser.parse_ref(self.cmd, None, raw_val));
                    let external_id = Id::from_static_ref(Id::EXTERNAL);
                    sc_m.add_val_to(&external_id, val, raw_val.to_os_string());
                }

                matcher.subcommand(SubCommand {
                    name: sc_name,
                    matches: sc_m.into_inner(),
                });

                ok!(self.resolve_pending(matcher));
                #[cfg(feature = "env")]
                ok!(self.add_env(matcher));
                ok!(self.add_defaults(matcher));
                return Validator::new(self.cmd).validate(parse_state, matcher);
            } else {
                // Start error processing
                let _ = self.resolve_pending(matcher);
                return Err(self.match_arg_error(&arg_os, valid_arg_found, trailing_values));
            }
        }

        if let Some(ref pos_sc_name) = subcmd_name {
            let sc_name = self
                .cmd
                .find_subcommand(pos_sc_name)
                .expect(INTERNAL_ERROR_MSG)
                .get_name()
                .to_owned();
            ok!(self.parse_subcommand(&sc_name, matcher, raw_args, args_cursor, keep_state));
        }

        ok!(self.resolve_pending(matcher));
        #[cfg(feature = "env")]
        ok!(self.add_env(matcher));
        ok!(self.add_defaults(matcher));
        Validator::new(self.cmd).validate(parse_state, matcher)
    }

    fn match_arg_error(
        &self,
        arg_os: &clap_lex::ParsedArg<'_>,
        valid_arg_found: bool,
        trailing_values: bool,
    ) -> ClapError {
        // If argument follows a `--`
        if trailing_values {
            // If the arg matches a subcommand name, or any of its aliases (if defined)
            if self
                .possible_subcommand(arg_os.to_value(), valid_arg_found)
                .is_some()
            {
                return ClapError::unnecessary_double_dash(
                    self.cmd,
                    arg_os.display().to_string(),
                    Usage::new(self.cmd).create_usage_with_title(&[]),
                );
            }
        }

        let candidates = suggestions::did_you_mean(
            &arg_os.display().to_string(),
            self.cmd.all_subcommand_names(),
        );
        // If the argument looks like a subcommand.
        if !candidates.is_empty() {
            return ClapError::invalid_subcommand(
                self.cmd,
                arg_os.display().to_string(),
                candidates,
                self.cmd
                    .get_bin_name()
                    .unwrap_or_else(|| self.cmd.get_name())
                    .to_owned(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            );
        }

        // If the argument must be a subcommand.
        if self.cmd.has_subcommands()
            && (!self.cmd.has_positionals() || self.cmd.is_infer_subcommands_set())
        {
            return ClapError::unrecognized_subcommand(
                self.cmd,
                arg_os.display().to_string(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            );
        }

        let suggested_trailing_arg = !trailing_values
            && self.cmd.has_positionals()
            && (arg_os.is_long() || arg_os.is_short());
        ClapError::unknown_argument(
            self.cmd,
            arg_os.display().to_string(),
            None,
            suggested_trailing_arg,
            Usage::new(self.cmd).create_usage_with_title(&[]),
        )
    }

    // Checks if the arg matches a subcommand name, or any of its aliases (if defined)
    fn possible_subcommand(
        &self,
        arg: Result<&str, &RawOsStr>,
        valid_arg_found: bool,
    ) -> Option<&str> {
        debug!("Parser::possible_subcommand: arg={:?}", arg);
        let arg = some!(arg.ok());

        if !(self.cmd.is_args_conflicts_with_subcommands_set() && valid_arg_found) {
            if self.cmd.is_infer_subcommands_set() {
                // For subcommand `test`, we accepts it's prefix: `t`, `te`,
                // `tes` and `test`.
                let v = self
                    .cmd
                    .all_subcommand_names()
                    .filter(|s| s.starts_with(arg))
                    .collect::<Vec<_>>();

                if v.len() == 1 {
                    return Some(v[0]);
                }

                // If there is any ambiguity, fallback to non-infer subcommand
                // search.
            }
            if let Some(sc) = self.cmd.find_subcommand(arg) {
                return Some(sc.get_name());
            }
        }
        None
    }

    // Checks if the arg matches a long flag subcommand name, or any of its aliases (if defined)
    fn possible_long_flag_subcommand(&self, arg: &str) -> Option<&str> {
        debug!("Parser::possible_long_flag_subcommand: arg={:?}", arg);
        if self.cmd.is_infer_subcommands_set() {
            let options = self
                .cmd
                .get_subcommands()
                .fold(Vec::new(), |mut options, sc| {
                    if let Some(long) = sc.get_long_flag() {
                        if long.starts_with(arg) {
                            options.push(long);
                        }
                        options.extend(sc.get_all_aliases().filter(|alias| alias.starts_with(arg)))
                    }
                    options
                });
            if options.len() == 1 {
                return Some(options[0]);
            }

            for sc in options {
                if sc == arg {
                    return Some(sc);
                }
            }
        } else if let Some(sc_name) = self.cmd.find_long_subcmd(arg) {
            return Some(sc_name);
        }
        None
    }

    fn parse_help_subcommand(
        &self,
        cmds: impl Iterator<Item = &'cmd OsStr>,
    ) -> ClapResult<std::convert::Infallible> {
        debug!("Parser::parse_help_subcommand");

        let mut cmd = self.cmd.clone();
        let sc = {
            let mut sc = &mut cmd;

            for cmd in cmds {
                sc = if let Some(sc_name) =
                    sc.find_subcommand(cmd).map(|sc| sc.get_name().to_owned())
                {
                    sc._build_subcommand(&sc_name).unwrap()
                } else {
                    return Err(ClapError::unrecognized_subcommand(
                        sc,
                        cmd.to_string_lossy().into_owned(),
                        Usage::new(sc).create_usage_with_title(&[]),
                    ));
                };
            }

            sc
        };
        let parser = Parser::new(sc);

        Err(parser.help_err(true))
    }

    fn is_new_arg(&self, next: &clap_lex::ParsedArg<'_>, current_positional: &Arg) -> bool {
        #![allow(clippy::needless_bool)] // Prefer consistent if/else-if ladder

        debug!(
            "Parser::is_new_arg: {:?}:{}",
            next.to_value_os(),
            current_positional.get_id()
        );

        if self.cmd[current_positional.get_id()].is_allow_hyphen_values_set()
            || (self.cmd[current_positional.get_id()].is_allow_negative_numbers_set()
                && next.is_number())
        {
            // If allow hyphen, this isn't a new arg.
            debug!("Parser::is_new_arg: Allow hyphen");
            false
        } else if next.is_long() {
            // If this is a long flag, this is a new arg.
            debug!("Parser::is_new_arg: --<something> found");
            true
        } else if next.is_short() {
            // If this is a short flag, this is a new arg. But a singe '-' by
            // itself is a value and typically means "stdin" on unix systems.
            debug!("Parser::is_new_arg: -<something> found");
            true
        } else {
            // Nothing special, this is a value.
            debug!("Parser::is_new_arg: value");
            false
        }
    }

    fn parse_subcommand(
        &mut self,
        sc_name: &str,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
        keep_state: bool,
    ) -> ClapResult<()> {
        debug!("Parser::parse_subcommand");

        let partial_parsing_enabled = self.cmd.is_ignore_errors_set();

        if let Some(sc) = self.cmd._build_subcommand(sc_name) {
            let mut sc_matcher = ArgMatcher::new(sc);

            debug!(
                "Parser::parse_subcommand: About to parse sc={}",
                sc.get_name()
            );

            {
                let mut p = Parser::new(sc);
                // HACK: maintain indexes between parsers
                // FlagSubCommand short arg needs to revisit the current short args, but skip the subcommand itself
                if keep_state {
                    p.cur_idx.set(self.cur_idx.get());
                    p.flag_subcmd_at = self.flag_subcmd_at;
                    p.flag_subcmd_skip = self.flag_subcmd_skip;
                }
                if let Err(error) = p.get_matches_with(&mut sc_matcher, raw_args, args_cursor) {
                    if partial_parsing_enabled {
                        debug!(
                            "Parser::parse_subcommand: ignored error in subcommand {}: {:?}",
                            sc_name, error
                        );
                    } else {
                        return Err(error);
                    }
                }
            }
            matcher.subcommand(SubCommand {
                name: sc.get_name().to_owned(),
                matches: sc_matcher.into_inner(),
            });
        }
        Ok(())
    }

    fn parse_long_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        long_arg: Result<&str, &RawOsStr>,
        long_value: Option<&RawOsStr>,
        parse_state: &ParseState,
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        // maybe here lifetime should be 'a
        debug!("Parser::parse_long_arg");

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
            self.cmd[opt].is_allow_hyphen_values_set())
        {
            debug!("Parser::parse_long_arg: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        }

        debug!("Parser::parse_long_arg: Does it contain '='...");
        let long_arg = match long_arg {
            Ok(long_arg) => long_arg,
            Err(long_arg) => {
                return Ok(ParseResult::NoMatchingArg {
                    arg: long_arg.to_str_lossy().into_owned(),
                });
            }
        };
        if long_arg.is_empty() {
            debug_assert!(
                long_value.is_some(),
                "`--` should be filtered out before this point"
            );
        }

        let arg = if let Some(arg) = self.cmd.get_keymap().get(long_arg) {
            debug!("Parser::parse_long_arg: Found valid arg or flag '{}'", arg);
            Some((long_arg, arg))
        } else if self.cmd.is_infer_long_args_set() {
            self.cmd.get_arguments().find_map(|a| {
                if let Some(long) = a.get_long() {
                    if long.starts_with(long_arg) {
                        return Some((long, a));
                    }
                }
                a.aliases
                    .iter()
                    .find_map(|(alias, _)| alias.starts_with(long_arg).then(|| (alias.as_str(), a)))
            })
        } else {
            None
        };

        if let Some((_long_arg, arg)) = arg {
            let ident = Identifier::Long;
            *valid_arg_found = true;
            if arg.is_takes_value_set() {
                debug!(
                    "Parser::parse_long_arg({:?}): Found an arg with value '{:?}'",
                    long_arg, &long_value
                );
                let has_eq = long_value.is_some();
                self.parse_opt_value(ident, long_value, arg, matcher, has_eq)
            } else if let Some(rest) = long_value {
                let required = self.cmd.required_graph();
                debug!(
                    "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                    long_arg, rest
                );
                let mut used: Vec<Id> = matcher
                    .arg_ids()
                    .filter(|arg_id| {
                        matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    })
                    .filter(|&n| {
                        self.cmd.find(n).map_or(true, |a| {
                            !(a.is_hide_set() || required.contains(a.get_id()))
                        })
                    })
                    .cloned()
                    .collect();
                used.push(arg.get_id().clone());

                Ok(ParseResult::UnneededAttachedValue {
                    rest: rest.to_str_lossy().into_owned(),
                    used,
                    arg: arg.to_string(),
                })
            } else {
                debug!("Parser::parse_long_arg({:?}): Presence validated", long_arg);
                let trailing_idx = None;
                self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    vec![],
                    trailing_idx,
                    matcher,
                )
            }
        } else if let Some(sc_name) = self.possible_long_flag_subcommand(long_arg) {
            Ok(ParseResult::FlagSubCommand(sc_name.to_string()))
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
        {
            debug!(
                "Parser::parse_long_args: positional at {} allows hyphens",
                pos_counter
            );
            Ok(ParseResult::MaybeHyphenValue)
        } else {
            Ok(ParseResult::NoMatchingArg {
                arg: long_arg.to_owned(),
            })
        }
    }

    fn parse_short_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        mut short_arg: clap_lex::ShortFlags<'_>,
        parse_state: &ParseState,
        // change this to possible pos_arg when removing the usage of &mut Parser.
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        debug!("Parser::parse_short_arg: short_arg={:?}", short_arg);

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt)
                if self.cmd[opt].is_allow_hyphen_values_set() || (self.cmd[opt].is_allow_negative_numbers_set() && short_arg.is_number()))
        {
            debug!("Parser::parse_short_args: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| arg.is_allow_negative_numbers_set())
            && short_arg.is_number()
        {
            debug!("Parser::parse_short_arg: negative number");
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
            && short_arg
                .clone()
                .any(|c| !c.map(|c| self.cmd.contains_short(c)).unwrap_or_default())
        {
            debug!(
                "Parser::parse_short_args: positional at {} allows hyphens",
                pos_counter
            );
            return Ok(ParseResult::MaybeHyphenValue);
        }

        let mut ret = ParseResult::NoArg;

        let skip = self.flag_subcmd_skip;
        self.flag_subcmd_skip = 0;
        let res = short_arg.advance_by(skip);
        debug_assert_eq!(
            res,
            Ok(()),
            "tracking of `flag_subcmd_skip` is off for `{:?}`",
            short_arg
        );
        while let Some(c) = short_arg.next_flag() {
            let c = match c {
                Ok(c) => c,
                Err(rest) => {
                    return Ok(ParseResult::NoMatchingArg {
                        arg: format!("-{}", rest.to_str_lossy()),
                    });
                }
            };
            debug!("Parser::parse_short_arg:iter:{}", c);

            // Check for matching short options, and return the name if there is no trailing
            // concatenated value: -oval
            // Option: -o
            // Value: val
            if let Some(arg) = self.cmd.get_keymap().get(&c) {
                let ident = Identifier::Short;
                debug!(
                    "Parser::parse_short_arg:iter:{}: Found valid opt or flag",
                    c
                );
                *valid_arg_found = true;
                if !arg.is_takes_value_set() {
                    let arg_values = Vec::new();
                    let trailing_idx = None;
                    ret = ok!(self.react(
                        Some(ident),
                        ValueSource::CommandLine,
                        arg,
                        arg_values,
                        trailing_idx,
                        matcher,
                    ));
                    continue;
                }

                // Check for trailing concatenated value
                //
                // Cloning the iterator, so we rollback if it isn't there.
                let val = short_arg.clone().next_value_os().unwrap_or_default();
                debug!(
                    "Parser::parse_short_arg:iter:{}: val={:?} (bytes), val={:?} (ascii), short_arg={:?}",
                    c, val, val.as_raw_bytes(), short_arg
                );
                let val = Some(val).filter(|v| !v.is_empty());

                // Default to "we're expecting a value later".
                //
                // If attached value is not consumed, we may have more short
                // flags to parse, continue.
                //
                // e.g. `-xvf`, when require_equals && x.min_vals == 0, we don't
                // consume the `vf`, even if it's provided as value.
                let (val, has_eq) = if let Some(val) = val.and_then(|v| v.strip_prefix('=')) {
                    (Some(val), true)
                } else {
                    (val, false)
                };
                match ok!(self.parse_opt_value(ident, val, arg, matcher, has_eq)) {
                    ParseResult::AttachedValueNotConsumed => continue,
                    x => return Ok(x),
                }
            }

            return if let Some(sc_name) = self.cmd.find_short_subcmd(c) {
                debug!("Parser::parse_short_arg:iter:{}: subcommand={}", c, sc_name);
                // Make sure indices get updated before reading `self.cur_idx`
                ok!(self.resolve_pending(matcher));
                self.cur_idx.set(self.cur_idx.get() + 1);
                debug!("Parser::parse_short_arg: cur_idx:={}", self.cur_idx.get());

                let name = sc_name.to_string();
                // Get the index of the previously saved flag subcommand in the group of flags (if exists).
                // If it is a new flag subcommand, then the formentioned index should be the current one
                // (ie. `cur_idx`), and should be registered.
                let cur_idx = self.cur_idx.get();
                self.flag_subcmd_at.get_or_insert(cur_idx);
                let done_short_args = short_arg.is_empty();
                if done_short_args {
                    self.flag_subcmd_at = None;
                }
                Ok(ParseResult::FlagSubCommand(name))
            } else {
                Ok(ParseResult::NoMatchingArg {
                    arg: format!("-{}", c),
                })
            };
        }
        Ok(ret)
    }

pub fn is_allow_negative_numbers_set(&self) -> bool

Report whether Arg::allow_negative_numbers is set

Examples found in repository

src/parser/parser.rs (line 651)

    fn is_new_arg(&self, next: &clap_lex::ParsedArg<'_>, current_positional: &Arg) -> bool {
        #![allow(clippy::needless_bool)] // Prefer consistent if/else-if ladder

        debug!(
            "Parser::is_new_arg: {:?}:{}",
            next.to_value_os(),
            current_positional.get_id()
        );

        if self.cmd[current_positional.get_id()].is_allow_hyphen_values_set()
            || (self.cmd[current_positional.get_id()].is_allow_negative_numbers_set()
                && next.is_number())
        {
            // If allow hyphen, this isn't a new arg.
            debug!("Parser::is_new_arg: Allow hyphen");
            false
        } else if next.is_long() {
            // If this is a long flag, this is a new arg.
            debug!("Parser::is_new_arg: --<something> found");
            true
        } else if next.is_short() {
            // If this is a short flag, this is a new arg. But a singe '-' by
            // itself is a value and typically means "stdin" on unix systems.
            debug!("Parser::is_new_arg: -<something> found");
            true
        } else {
            // Nothing special, this is a value.
            debug!("Parser::is_new_arg: value");
            false
        }
    }

    fn parse_subcommand(
        &mut self,
        sc_name: &str,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
        keep_state: bool,
    ) -> ClapResult<()> {
        debug!("Parser::parse_subcommand");

        let partial_parsing_enabled = self.cmd.is_ignore_errors_set();

        if let Some(sc) = self.cmd._build_subcommand(sc_name) {
            let mut sc_matcher = ArgMatcher::new(sc);

            debug!(
                "Parser::parse_subcommand: About to parse sc={}",
                sc.get_name()
            );

            {
                let mut p = Parser::new(sc);
                // HACK: maintain indexes between parsers
                // FlagSubCommand short arg needs to revisit the current short args, but skip the subcommand itself
                if keep_state {
                    p.cur_idx.set(self.cur_idx.get());
                    p.flag_subcmd_at = self.flag_subcmd_at;
                    p.flag_subcmd_skip = self.flag_subcmd_skip;
                }
                if let Err(error) = p.get_matches_with(&mut sc_matcher, raw_args, args_cursor) {
                    if partial_parsing_enabled {
                        debug!(
                            "Parser::parse_subcommand: ignored error in subcommand {}: {:?}",
                            sc_name, error
                        );
                    } else {
                        return Err(error);
                    }
                }
            }
            matcher.subcommand(SubCommand {
                name: sc.get_name().to_owned(),
                matches: sc_matcher.into_inner(),
            });
        }
        Ok(())
    }

    fn parse_long_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        long_arg: Result<&str, &RawOsStr>,
        long_value: Option<&RawOsStr>,
        parse_state: &ParseState,
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        // maybe here lifetime should be 'a
        debug!("Parser::parse_long_arg");

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
            self.cmd[opt].is_allow_hyphen_values_set())
        {
            debug!("Parser::parse_long_arg: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        }

        debug!("Parser::parse_long_arg: Does it contain '='...");
        let long_arg = match long_arg {
            Ok(long_arg) => long_arg,
            Err(long_arg) => {
                return Ok(ParseResult::NoMatchingArg {
                    arg: long_arg.to_str_lossy().into_owned(),
                });
            }
        };
        if long_arg.is_empty() {
            debug_assert!(
                long_value.is_some(),
                "`--` should be filtered out before this point"
            );
        }

        let arg = if let Some(arg) = self.cmd.get_keymap().get(long_arg) {
            debug!("Parser::parse_long_arg: Found valid arg or flag '{}'", arg);
            Some((long_arg, arg))
        } else if self.cmd.is_infer_long_args_set() {
            self.cmd.get_arguments().find_map(|a| {
                if let Some(long) = a.get_long() {
                    if long.starts_with(long_arg) {
                        return Some((long, a));
                    }
                }
                a.aliases
                    .iter()
                    .find_map(|(alias, _)| alias.starts_with(long_arg).then(|| (alias.as_str(), a)))
            })
        } else {
            None
        };

        if let Some((_long_arg, arg)) = arg {
            let ident = Identifier::Long;
            *valid_arg_found = true;
            if arg.is_takes_value_set() {
                debug!(
                    "Parser::parse_long_arg({:?}): Found an arg with value '{:?}'",
                    long_arg, &long_value
                );
                let has_eq = long_value.is_some();
                self.parse_opt_value(ident, long_value, arg, matcher, has_eq)
            } else if let Some(rest) = long_value {
                let required = self.cmd.required_graph();
                debug!(
                    "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                    long_arg, rest
                );
                let mut used: Vec<Id> = matcher
                    .arg_ids()
                    .filter(|arg_id| {
                        matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    })
                    .filter(|&n| {
                        self.cmd.find(n).map_or(true, |a| {
                            !(a.is_hide_set() || required.contains(a.get_id()))
                        })
                    })
                    .cloned()
                    .collect();
                used.push(arg.get_id().clone());

                Ok(ParseResult::UnneededAttachedValue {
                    rest: rest.to_str_lossy().into_owned(),
                    used,
                    arg: arg.to_string(),
                })
            } else {
                debug!("Parser::parse_long_arg({:?}): Presence validated", long_arg);
                let trailing_idx = None;
                self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    vec![],
                    trailing_idx,
                    matcher,
                )
            }
        } else if let Some(sc_name) = self.possible_long_flag_subcommand(long_arg) {
            Ok(ParseResult::FlagSubCommand(sc_name.to_string()))
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
        {
            debug!(
                "Parser::parse_long_args: positional at {} allows hyphens",
                pos_counter
            );
            Ok(ParseResult::MaybeHyphenValue)
        } else {
            Ok(ParseResult::NoMatchingArg {
                arg: long_arg.to_owned(),
            })
        }
    }

    fn parse_short_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        mut short_arg: clap_lex::ShortFlags<'_>,
        parse_state: &ParseState,
        // change this to possible pos_arg when removing the usage of &mut Parser.
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        debug!("Parser::parse_short_arg: short_arg={:?}", short_arg);

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt)
                if self.cmd[opt].is_allow_hyphen_values_set() || (self.cmd[opt].is_allow_negative_numbers_set() && short_arg.is_number()))
        {
            debug!("Parser::parse_short_args: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| arg.is_allow_negative_numbers_set())
            && short_arg.is_number()
        {
            debug!("Parser::parse_short_arg: negative number");
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
            && short_arg
                .clone()
                .any(|c| !c.map(|c| self.cmd.contains_short(c)).unwrap_or_default())
        {
            debug!(
                "Parser::parse_short_args: positional at {} allows hyphens",
                pos_counter
            );
            return Ok(ParseResult::MaybeHyphenValue);
        }

        let mut ret = ParseResult::NoArg;

        let skip = self.flag_subcmd_skip;
        self.flag_subcmd_skip = 0;
        let res = short_arg.advance_by(skip);
        debug_assert_eq!(
            res,
            Ok(()),
            "tracking of `flag_subcmd_skip` is off for `{:?}`",
            short_arg
        );
        while let Some(c) = short_arg.next_flag() {
            let c = match c {
                Ok(c) => c,
                Err(rest) => {
                    return Ok(ParseResult::NoMatchingArg {
                        arg: format!("-{}", rest.to_str_lossy()),
                    });
                }
            };
            debug!("Parser::parse_short_arg:iter:{}", c);

            // Check for matching short options, and return the name if there is no trailing
            // concatenated value: -oval
            // Option: -o
            // Value: val
            if let Some(arg) = self.cmd.get_keymap().get(&c) {
                let ident = Identifier::Short;
                debug!(
                    "Parser::parse_short_arg:iter:{}: Found valid opt or flag",
                    c
                );
                *valid_arg_found = true;
                if !arg.is_takes_value_set() {
                    let arg_values = Vec::new();
                    let trailing_idx = None;
                    ret = ok!(self.react(
                        Some(ident),
                        ValueSource::CommandLine,
                        arg,
                        arg_values,
                        trailing_idx,
                        matcher,
                    ));
                    continue;
                }

                // Check for trailing concatenated value
                //
                // Cloning the iterator, so we rollback if it isn't there.
                let val = short_arg.clone().next_value_os().unwrap_or_default();
                debug!(
                    "Parser::parse_short_arg:iter:{}: val={:?} (bytes), val={:?} (ascii), short_arg={:?}",
                    c, val, val.as_raw_bytes(), short_arg
                );
                let val = Some(val).filter(|v| !v.is_empty());

                // Default to "we're expecting a value later".
                //
                // If attached value is not consumed, we may have more short
                // flags to parse, continue.
                //
                // e.g. `-xvf`, when require_equals && x.min_vals == 0, we don't
                // consume the `vf`, even if it's provided as value.
                let (val, has_eq) = if let Some(val) = val.and_then(|v| v.strip_prefix('=')) {
                    (Some(val), true)
                } else {
                    (val, false)
                };
                match ok!(self.parse_opt_value(ident, val, arg, matcher, has_eq)) {
                    ParseResult::AttachedValueNotConsumed => continue,
                    x => return Ok(x),
                }
            }

            return if let Some(sc_name) = self.cmd.find_short_subcmd(c) {
                debug!("Parser::parse_short_arg:iter:{}: subcommand={}", c, sc_name);
                // Make sure indices get updated before reading `self.cur_idx`
                ok!(self.resolve_pending(matcher));
                self.cur_idx.set(self.cur_idx.get() + 1);
                debug!("Parser::parse_short_arg: cur_idx:={}", self.cur_idx.get());

                let name = sc_name.to_string();
                // Get the index of the previously saved flag subcommand in the group of flags (if exists).
                // If it is a new flag subcommand, then the formentioned index should be the current one
                // (ie. `cur_idx`), and should be registered.
                let cur_idx = self.cur_idx.get();
                self.flag_subcmd_at.get_or_insert(cur_idx);
                let done_short_args = short_arg.is_empty();
                if done_short_args {
                    self.flag_subcmd_at = None;
                }
                Ok(ParseResult::FlagSubCommand(name))
            } else {
                Ok(ParseResult::NoMatchingArg {
                    arg: format!("-{}", c),
                })
            };
        }
        Ok(ret)
    }

pub fn get_action(&self) -> &ArgAction

Behavior when parsing the argument

Examples found in repository

src/builder/arg.rs (line 3937)

    pub(crate) fn is_takes_value_set(&self) -> bool {
        self.get_action().takes_values()
    }

    /// Report whether [`Arg::allow_hyphen_values`] is set
    pub fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(ArgSettings::AllowHyphenValues)
    }

    /// Report whether [`Arg::allow_negative_numbers`] is set
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(ArgSettings::AllowNegativeNumbers)
    }

    /// Behavior when parsing the argument
    pub fn get_action(&self) -> &super::ArgAction {
        const DEFAULT: super::ArgAction = super::ArgAction::Set;
        self.action.as_ref().unwrap_or(&DEFAULT)
    }

    /// Configured parser for argument values
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .arg(
    ///         clap::Arg::new("port")
    ///             .value_parser(clap::value_parser!(usize))
    ///     );
    /// let value_parser = cmd.get_arguments()
    ///     .find(|a| a.get_id() == "port").unwrap()
    ///     .get_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_value_parser(&self) -> &super::ValueParser {
        if let Some(value_parser) = self.value_parser.as_ref() {
            value_parser
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::string();
            &DEFAULT
        }
    }

    /// Report whether [`Arg::global`] is set
    pub fn is_global_set(&self) -> bool {
        self.is_set(ArgSettings::Global)
    }

    /// Report whether [`Arg::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(ArgSettings::NextLineHelp)
    }

    /// Report whether [`Arg::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(ArgSettings::Hidden)
    }

    /// Report whether [`Arg::hide_default_value`] is set
    pub fn is_hide_default_value_set(&self) -> bool {
        self.is_set(ArgSettings::HideDefaultValue)
    }

    /// Report whether [`Arg::hide_possible_values`] is set
    pub fn is_hide_possible_values_set(&self) -> bool {
        self.is_set(ArgSettings::HidePossibleValues)
    }

    /// Report whether [`Arg::hide_env`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnv)
    }

    /// Report whether [`Arg::hide_env_values`] is set
    #[cfg(feature = "env")]
    pub fn is_hide_env_values_set(&self) -> bool {
        self.is_set(ArgSettings::HideEnvValues)
    }

    /// Report whether [`Arg::hide_short_help`] is set
    pub fn is_hide_short_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenShortHelp)
    }

    /// Report whether [`Arg::hide_long_help`] is set
    pub fn is_hide_long_help_set(&self) -> bool {
        self.is_set(ArgSettings::HiddenLongHelp)
    }

    /// Report whether [`Arg::require_equals`] is set
    pub fn is_require_equals_set(&self) -> bool {
        self.is_set(ArgSettings::RequireEquals)
    }

    /// Reports whether [`Arg::exclusive`] is set
    pub fn is_exclusive_set(&self) -> bool {
        self.is_set(ArgSettings::Exclusive)
    }

    /// Report whether [`Arg::trailing_var_arg`] is set
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(ArgSettings::TrailingVarArg)
    }

    /// Reports whether [`Arg::last`] is set
    pub fn is_last_set(&self) -> bool {
        self.is_set(ArgSettings::Last)
    }

    /// Reports whether [`Arg::ignore_case`] is set
    pub fn is_ignore_case_set(&self) -> bool {
        self.is_set(ArgSettings::IgnoreCase)
    }
}

/// # Internally used only
impl Arg {
    pub(crate) fn _build(&mut self) {
        if self.action.is_none() {
            if self.num_vals == Some(ValueRange::EMPTY) {
                let action = super::ArgAction::SetTrue;
                self.action = Some(action);
            } else {
                let action =
                    if self.is_positional() && self.num_vals.unwrap_or_default().is_unbounded() {
                        // Allow collecting arguments interleaved with flags
                        //
                        // Bounded values are probably a group and the user should explicitly opt-in to
                        // Append
                        super::ArgAction::Append
                    } else {
                        super::ArgAction::Set
                    };
                self.action = Some(action);
            }
        }
        if let Some(action) = self.action.as_ref() {
            if let Some(default_value) = action.default_value() {
                if self.default_vals.is_empty() {
                    self.default_vals = vec![default_value.into()];
                }
            }
            if let Some(default_value) = action.default_missing_value() {
                if self.default_missing_vals.is_empty() {
                    self.default_missing_vals = vec![default_value.into()];
                }
            }
        }

        if self.value_parser.is_none() {
            if let Some(default) = self.action.as_ref().and_then(|a| a.default_value_parser()) {
                self.value_parser = Some(default);
            } else {
                self.value_parser = Some(super::ValueParser::string());
            }
        }

        let val_names_len = self.val_names.len();
        if val_names_len > 1 {
            self.num_vals.get_or_insert(val_names_len.into());
        } else {
            let nargs = if self.get_action().takes_values() {
                ValueRange::SINGLE
            } else {
                ValueRange::EMPTY
            };
            self.num_vals.get_or_insert(nargs);
        }
    }

    // Used for positionals when printing
    pub(crate) fn name_no_brackets(&self) -> String {
        debug!("Arg::name_no_brackets:{}", self.get_id());
        let delim = " ";
        if !self.val_names.is_empty() {
            debug!("Arg::name_no_brackets: val_names={:#?}", self.val_names);

            if self.val_names.len() > 1 {
                self.val_names
                    .iter()
                    .map(|n| format!("<{}>", n))
                    .collect::<Vec<_>>()
                    .join(delim)
            } else {
                self.val_names
                    .first()
                    .expect(INTERNAL_ERROR_MSG)
                    .as_str()
                    .to_owned()
            }
        } else {
            debug!("Arg::name_no_brackets: just name");
            self.get_id().as_str().to_owned()
        }
    }

    pub(crate) fn stylized(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();
        // Write the name such --long or -l
        if let Some(l) = self.get_long() {
            styled.literal("--");
            styled.literal(l);
        } else if let Some(s) = self.get_short() {
            styled.literal("-");
            styled.literal(s);
        }
        styled.extend(self.stylize_arg_suffix(required).into_iter());
        styled
    }

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

    /// Write the values such as <name1> <name2>
    fn render_arg_val(&self, required: bool) -> String {
        let mut rendered = String::new();

        let num_vals = self.get_num_args().unwrap_or_else(|| 1.into());

        let mut val_names = if self.val_names.is_empty() {
            vec![self.id.as_internal_str().to_owned()]
        } else {
            self.val_names.clone()
        };
        if val_names.len() == 1 {
            let min = num_vals.min_values().max(1);
            let val_name = val_names.pop().unwrap();
            val_names = vec![val_name; min];
        }

        debug_assert!(self.is_takes_value_set());
        for (n, val_name) in val_names.iter().enumerate() {
            let arg_name = if self.is_positional() && (num_vals.min_values() == 0 || !required) {
                format!("[{}]", val_name)
            } else {
                format!("<{}>", val_name)
            };

            if n != 0 {
                rendered.push(' ');
            }
            rendered.push_str(&arg_name);
        }

        let mut extra_values = false;
        extra_values |= val_names.len() < num_vals.max_values();
        if self.is_positional() && matches!(*self.get_action(), ArgAction::Append) {
            extra_values = true;
        }
        if extra_values {
            rendered.push_str("...");
        }

        rendered
    }

    /// Either multiple values or occurrences
    pub(crate) fn is_multiple(&self) -> bool {
        self.is_multiple_values_set() || matches!(*self.get_action(), ArgAction::Append)
    }

src/parser/parser.rs (line 1175)

    fn react(
        &self,
        ident: Option<Identifier>,
        source: ValueSource,
        arg: &Arg,
        mut raw_vals: Vec<OsString>,
        mut trailing_idx: Option<usize>,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<ParseResult> {
        ok!(self.resolve_pending(matcher));

        debug!(
            "Parser::react action={:?}, identifier={:?}, source={:?}",
            arg.get_action(),
            ident,
            source
        );

        // Process before `default_missing_values` to avoid it counting as values from the command
        // line
        if source == ValueSource::CommandLine {
            ok!(self.verify_num_args(arg, &raw_vals));
        }

        if raw_vals.is_empty() {
            // We assume this case is valid: require equals, but min_vals == 0.
            if !arg.default_missing_vals.is_empty() {
                debug!("Parser::react: has default_missing_vals");
                trailing_idx = None;
                raw_vals.extend(
                    arg.default_missing_vals
                        .iter()
                        .map(|s| s.as_os_str().to_owned()),
                );
            }
        }

        if let Some(val_delim) = arg.get_value_delimiter() {
            if self.cmd.is_dont_delimit_trailing_values_set() && trailing_idx == Some(0) {
                // Nothing to do
            } else {
                let mut split_raw_vals = Vec::with_capacity(raw_vals.len());
                for (i, raw_val) in raw_vals.into_iter().enumerate() {
                    let raw_val = RawOsString::new(raw_val);
                    if !raw_val.contains(val_delim)
                        || (self.cmd.is_dont_delimit_trailing_values_set()
                            && trailing_idx == Some(i))
                    {
                        split_raw_vals.push(raw_val.into_os_string());
                    } else {
                        split_raw_vals
                            .extend(raw_val.split(val_delim).map(|x| x.to_os_str().into_owned()));
                    }
                }
                raw_vals = split_raw_vals
            }
        }

        match arg.get_action() {
            ArgAction::Set => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Append => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetTrue => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("true")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetFalse => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("false")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Count => {
                let raw_vals = if raw_vals.is_empty() {
                    let existing_value = *matcher
                        .get_one::<crate::builder::CountType>(arg.get_id().as_str())
                        .unwrap_or(&0);
                    let next_value = existing_value.saturating_add(1);
                    vec![OsString::from(next_value.to_string())]
                } else {
                    raw_vals
                };

                matcher.remove(arg.get_id());
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Help => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Help: use_long={}", use_long);
                Err(self.help_err(use_long))
            }
            ArgAction::Version => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Version: use_long={}", use_long);
                Err(self.version_err(use_long))
            }
        }
    }

src/builder/debug_asserts.rs (line 32)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn get_value_parser(&self) -> &ValueParser

Configured parser for argument values

Example

let cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("port")
            .value_parser(clap::value_parser!(usize))
    );
let value_parser = cmd.get_arguments()
    .find(|a| a.get_id() == "port").unwrap()
    .get_value_parser();
println!("{:?}", value_parser);

Examples found in repository

src/parser/validator.rs (line 539)

pub(crate) fn get_possible_values_cli(a: &Arg) -> Vec<PossibleValue> {
    if !a.is_takes_value_set() {
        vec![]
    } else {
        a.get_value_parser()
            .possible_values()
            .map(|pvs| pvs.collect())
            .unwrap_or_default()
    }
}

src/builder/arg.rs (line 3827)

    pub fn get_possible_values(&self) -> Vec<PossibleValue> {
        if !self.is_takes_value_set() {
            vec![]
        } else {
            self.get_value_parser()
                .possible_values()
                .map(|pvs| pvs.collect())
                .unwrap_or_default()
        }
    }

    /// Get the names of values for this argument.
    #[inline]
    pub fn get_value_names(&self) -> Option<&[Str]> {
        if self.val_names.is_empty() {
            None
        } else {
            Some(&self.val_names)
        }
    }

    /// Get the number of values for this argument.
    #[inline]
    pub fn get_num_args(&self) -> Option<ValueRange> {
        self.num_vals
    }

    #[inline]
    pub(crate) fn get_min_vals(&self) -> usize {
        self.get_num_args().expect(INTERNAL_ERROR_MSG).min_values()
    }

    /// Get the delimiter between multiple values
    #[inline]
    pub fn get_value_delimiter(&self) -> Option<char> {
        self.val_delim
    }

    /// Get the index of this argument, if any
    #[inline]
    pub fn get_index(&self) -> Option<usize> {
        self.index
    }

    /// Get the value hint of this argument
    pub fn get_value_hint(&self) -> ValueHint {
        self.value_hint.unwrap_or_else(|| {
            if self.is_takes_value_set() {
                let type_id = self.get_value_parser().type_id();
                if type_id == crate::parser::AnyValueId::of::<std::path::PathBuf>() {
                    ValueHint::AnyPath
                } else {
                    ValueHint::default()
                }
            } else {
                ValueHint::default()
            }
        })
    }

src/parser/matches/matched_arg.rs (line 31)

    pub(crate) fn new_arg(arg: &crate::Arg) -> Self {
        let ignore_case = arg.is_ignore_case_set();
        Self {
            source: None,
            indices: Vec::new(),
            type_id: Some(arg.get_value_parser().type_id()),
            vals: Vec::new(),
            raw_vals: Vec::new(),
            ignore_case,
        }
    }

src/parser/arg_matcher.rs (line 139)

    pub(crate) fn start_custom_arg(&mut self, arg: &Arg, source: ValueSource) {
        let id = arg.get_id().clone();
        debug!(
            "ArgMatcher::start_custom_arg: id={:?}, source={:?}",
            id, source
        );
        let ma = self.entry(id).or_insert(MatchedArg::new_arg(arg));
        debug_assert_eq!(ma.type_id(), Some(arg.get_value_parser().type_id()));
        ma.set_source(source);
        ma.new_val_group();
    }

src/parser/parser.rs (line 1085)

    fn push_arg_values(
        &self,
        arg: &Arg,
        raw_vals: Vec<OsString>,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<()> {
        debug!("Parser::push_arg_values: {:?}", raw_vals);

        for raw_val in raw_vals {
            // update the current index because each value is a distinct index to clap
            self.cur_idx.set(self.cur_idx.get() + 1);
            debug!(
                "Parser::add_single_val_to_arg: cur_idx:={}",
                self.cur_idx.get()
            );
            let value_parser = arg.get_value_parser();
            let val = ok!(value_parser.parse_ref(self.cmd, Some(arg), &raw_val));

            matcher.add_val_to(arg.get_id(), val, raw_val);
            matcher.add_index_to(arg.get_id(), self.cur_idx.get());
        }

        Ok(())
    }

src/builder/debug_asserts.rs (line 710)

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

fn assert_arg_flags(arg: &Arg) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if arg.$a() {
                let mut s = String::new();

                $(
                    if !arg.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  Arg::{} is required when Arg::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("Argument {:?}\n{}", arg.get_id(), s)
                }
            }
        }
    }

    checker!(is_hide_possible_values_set requires is_takes_value_set);
    checker!(is_allow_hyphen_values_set requires is_takes_value_set);
    checker!(is_allow_negative_numbers_set requires is_takes_value_set);
    checker!(is_require_equals_set requires is_takes_value_set);
    checker!(is_last_set requires is_takes_value_set);
    checker!(is_hide_default_value_set requires is_takes_value_set);
    checker!(is_multiple_values_set requires is_takes_value_set);
    checker!(is_ignore_case_set requires is_takes_value_set);
}

fn assert_defaults<'d>(
    arg: &Arg,
    field: &'static str,
    defaults: impl IntoIterator<Item = &'d OsStr>,
) {
    for default_os in defaults {
        let value_parser = arg.get_value_parser();
        let assert_cmd = Command::new("assert");
        if let Some(delim) = arg.get_value_delimiter() {
            let default_os = RawOsStr::new(default_os);
            for part in default_os.split(delim) {
                if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), &part.to_os_str())
                {
                    panic!(
                        "Argument `{}`'s {}={:?} failed validation: {}",
                        arg.get_id(),
                        field,
                        part.to_str_lossy(),
                        err
                    );
                }
            }
        } else if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), default_os) {
            panic!(
                "Argument `{}`'s {}={:?} failed validation: {}",
                arg.get_id(),
                field,
                default_os,
                err
            );
        }
    }
}

pub fn is_global_set(&self) -> bool

Report whether Arg::global is set

Examples found in repository

src/builder/command.rs (line 3481)

    pub fn get_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        if arg.is_global_set() {
            self.get_global_arg_conflicts_with(arg)
        } else {
            let mut result = Vec::new();
            for id in arg.blacklist.iter() {
                if let Some(arg) = self.find(id) {
                    result.push(arg);
                } else if let Some(group) = self.find_group(id) {
                    result.extend(
                        self.unroll_args_in_group(&group.id)
                            .iter()
                            .map(|id| self.find(id).expect(INTERNAL_ERROR_MSG)),
                    );
                } else {
                    panic!("Command::get_arg_conflicts_with: The passed arg conflicts with an arg unknown to the cmd");
                }
            }
            result
        }
    }

    // Get a unique list of all arguments of all commands and continuous subcommands the given argument conflicts with.
    //
    // This behavior follows the propagation rules of global arguments.
    // It is useful for finding conflicts for arguments declared as global.
    //
    // ### Panics
    //
    // If the given arg contains a conflict with an argument that is unknown to
    // this `Command`.
    fn get_global_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        arg.blacklist
            .iter()
            .map(|id| {
                self.args
                    .args()
                    .chain(
                        self.get_subcommands_containing(arg)
                            .iter()
                            .flat_map(|x| x.args.args()),
                    )
                    .find(|arg| arg.get_id() == id)
                    .expect(
                        "Command::get_arg_conflicts_with: \
                    The passed arg conflicts with an arg unknown to the cmd",
                    )
            })
            .collect()
    }

    // Get a list of subcommands which contain the provided Argument
    //
    // This command will only include subcommands in its list for which the subcommands
    // parent also contains the Argument.
    //
    // This search follows the propagation rules of global arguments.
    // It is useful to finding subcommands, that have inherited a global argument.
    //
    // **NOTE:** In this case only Sucommand_1 will be included
    //   Subcommand_1 (contains Arg)
    //     Subcommand_1.1 (doesn't contain Arg)
    //       Subcommand_1.1.1 (contains Arg)
    //
    fn get_subcommands_containing(&self, arg: &Arg) -> Vec<&Self> {
        let mut vec = std::vec::Vec::new();
        for idx in 0..self.subcommands.len() {
            if self.subcommands[idx]
                .args
                .args()
                .any(|ar| ar.get_id() == arg.get_id())
            {
                vec.push(&self.subcommands[idx]);
                vec.append(&mut self.subcommands[idx].get_subcommands_containing(arg));
            }
        }
        vec
    }

    /// Report whether [`Command::no_binary_name`] is set
    pub fn is_no_binary_name_set(&self) -> bool {
        self.is_set(AppSettings::NoBinaryName)
    }

    /// Report whether [`Command::ignore_errors`] is set
    pub(crate) fn is_ignore_errors_set(&self) -> bool {
        self.is_set(AppSettings::IgnoreErrors)
    }

    /// Report whether [`Command::dont_delimit_trailing_values`] is set
    pub fn is_dont_delimit_trailing_values_set(&self) -> bool {
        self.is_set(AppSettings::DontDelimitTrailingValues)
    }

    /// Report whether [`Command::disable_version_flag`] is set
    pub fn is_disable_version_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableVersionFlag)
            || (self.version.is_none() && self.long_version.is_none())
    }

    /// Report whether [`Command::propagate_version`] is set
    pub fn is_propagate_version_set(&self) -> bool {
        self.is_set(AppSettings::PropagateVersion)
    }

    /// Report whether [`Command::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(AppSettings::NextLineHelp)
    }

    /// Report whether [`Command::disable_help_flag`] is set
    pub fn is_disable_help_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpFlag)
    }

    /// Report whether [`Command::disable_help_subcommand`] is set
    pub fn is_disable_help_subcommand_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpSubcommand)
    }

    /// Report whether [`Command::disable_colored_help`] is set
    pub fn is_disable_colored_help_set(&self) -> bool {
        self.is_set(AppSettings::DisableColoredHelp)
    }

    /// Report whether [`Command::help_expected`] is set
    #[cfg(debug_assertions)]
    pub(crate) fn is_help_expected_set(&self) -> bool {
        self.is_set(AppSettings::HelpExpected)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn is_dont_collapse_args_in_usage_set(&self) -> bool {
        true
    }

    /// Report whether [`Command::infer_long_args`] is set
    pub(crate) fn is_infer_long_args_set(&self) -> bool {
        self.is_set(AppSettings::InferLongArgs)
    }

    /// Report whether [`Command::infer_subcommands`] is set
    pub(crate) fn is_infer_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::InferSubcommands)
    }

    /// Report whether [`Command::arg_required_else_help`] is set
    pub fn is_arg_required_else_help_set(&self) -> bool {
        self.is_set(AppSettings::ArgRequiredElseHelp)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_hyphen_values_set`"
        )
    )]
    pub(crate) fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(AppSettings::AllowHyphenValues)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_negative_numbers_set`"
        )
    )]
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(AppSettings::AllowNegativeNumbers)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::is_trailing_var_arg_set`")
    )]
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(AppSettings::TrailingVarArg)
    }

    /// Report whether [`Command::allow_missing_positional`] is set
    pub fn is_allow_missing_positional_set(&self) -> bool {
        self.is_set(AppSettings::AllowMissingPositional)
    }

    /// Report whether [`Command::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(AppSettings::Hidden)
    }

    /// Report whether [`Command::subcommand_required`] is set
    pub fn is_subcommand_required_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandRequired)
    }

    /// Report whether [`Command::allow_external_subcommands`] is set
    pub fn is_allow_external_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::AllowExternalSubcommands)
    }

    /// Configured parser for values passed to an external subcommand
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .external_subcommand_value_parser(clap::value_parser!(String));
    /// let value_parser = cmd.get_external_subcommand_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_external_subcommand_value_parser(&self) -> Option<&super::ValueParser> {
        if !self.is_allow_external_subcommands_set() {
            None
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::os_string();
            Some(self.external_value_parser.as_ref().unwrap_or(&DEFAULT))
        }
    }

    /// Report whether [`Command::args_conflicts_with_subcommands`] is set
    pub fn is_args_conflicts_with_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::ArgsNegateSubcommands)
    }

    #[doc(hidden)]
    pub fn is_args_override_self(&self) -> bool {
        self.is_set(AppSettings::AllArgsOverrideSelf)
    }

    /// Report whether [`Command::subcommand_precedence_over_arg`] is set
    pub fn is_subcommand_precedence_over_arg_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandPrecedenceOverArg)
    }

    /// Report whether [`Command::subcommand_negates_reqs`] is set
    pub fn is_subcommand_negates_reqs_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandsNegateReqs)
    }

    /// Report whether [`Command::multicall`] is set
    pub fn is_multicall_set(&self) -> bool {
        self.is_set(AppSettings::Multicall)
    }
}

// Internally used only
impl Command {
    pub(crate) fn get_override_usage(&self) -> Option<&StyledStr> {
        self.usage_str.as_ref()
    }

    pub(crate) fn get_override_help(&self) -> Option<&StyledStr> {
        self.help_str.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_help_template(&self) -> Option<&StyledStr> {
        self.template.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_term_width(&self) -> Option<usize> {
        self.term_w
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_max_term_width(&self) -> Option<usize> {
        self.max_w
    }

    pub(crate) fn get_replacement(&self, key: &str) -> Option<&[Str]> {
        self.replacers.get(key).map(|v| v.as_slice())
    }

    pub(crate) fn get_keymap(&self) -> &MKeyMap {
        &self.args
    }

    fn get_used_global_args(&self, matches: &ArgMatches, global_arg_vec: &mut Vec<Id>) {
        global_arg_vec.extend(
            self.args
                .args()
                .filter(|a| a.is_global_set())
                .map(|ga| ga.id.clone()),
        );
        if let Some((id, matches)) = matches.subcommand() {
            if let Some(used_sub) = self.find_subcommand(id) {
                used_sub.get_used_global_args(matches, global_arg_vec);
            }
        }
    }

    fn _do_parse(
        &mut self,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<ArgMatches> {
        debug!("Command::_do_parse");

        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing in case we run into a subcommand
        self._build_self(false);

        let mut matcher = ArgMatcher::new(self);

        // do the real parsing
        let mut parser = Parser::new(self);
        if let Err(error) = parser.get_matches_with(&mut matcher, raw_args, args_cursor) {
            if self.is_set(AppSettings::IgnoreErrors) {
                debug!("Command::_do_parse: ignoring error: {}", error);
            } else {
                return Err(error);
            }
        }

        let mut global_arg_vec = Default::default();
        self.get_used_global_args(&matcher, &mut global_arg_vec);

        matcher.propagate_globals(&global_arg_vec);

        Ok(matcher.into_inner())
    }

    /// Prepare for introspecting on all included [`Command`]s
    ///
    /// Call this on the top-level [`Command`] when done building and before reading state for
    /// cases like completions, custom help output, etc.
    pub fn build(&mut self) {
        self._build_recursive(true);
        self._build_bin_names_internal();
    }

    pub(crate) fn _build_recursive(&mut self, expand_help_tree: bool) {
        self._build_self(expand_help_tree);
        for subcmd in self.get_subcommands_mut() {
            subcmd._build_recursive(expand_help_tree);
        }
    }

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

    pub(crate) fn _build_subcommand(&mut self, name: &str) -> Option<&mut Self> {
        use std::fmt::Write;

        let mut mid_string = String::from(" ");
        #[cfg(feature = "usage")]
        if !self.is_subcommand_negates_reqs_set() && !self.is_args_conflicts_with_subcommands_set()
        {
            let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

            for s in &reqs {
                mid_string.push_str(&s.to_string());
                mid_string.push(' ');
            }
        }
        let is_multicall_set = self.is_multicall_set();

        let sc = some!(self.subcommands.iter_mut().find(|s| s.name == name));

        // Display subcommand name, short and long in usage
        let mut sc_names = String::new();
        sc_names.push_str(sc.name.as_str());
        let mut flag_subcmd = false;
        if let Some(l) = sc.get_long_flag() {
            write!(sc_names, "|--{}", l).unwrap();
            flag_subcmd = true;
        }
        if let Some(s) = sc.get_short_flag() {
            write!(sc_names, "|-{}", s).unwrap();
            flag_subcmd = true;
        }

        if flag_subcmd {
            sc_names = format!("{{{}}}", sc_names);
        }

        let usage_name = self
            .bin_name
            .as_ref()
            .map(|bin_name| format!("{}{}{}", bin_name, mid_string, sc_names))
            .unwrap_or(sc_names);
        sc.usage_name = Some(usage_name);

        // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
        // a space
        let bin_name = format!(
            "{}{}{}",
            self.bin_name.as_deref().unwrap_or_default(),
            if self.bin_name.is_some() { " " } else { "" },
            &*sc.name
        );
        debug!(
            "Command::_build_subcommand Setting bin_name of {} to {:?}",
            sc.name, bin_name
        );
        sc.bin_name = Some(bin_name);

        if sc.display_name.is_none() {
            let self_display_name = if is_multicall_set {
                self.display_name.as_deref().unwrap_or("")
            } else {
                self.display_name.as_deref().unwrap_or(&self.name)
            };
            let display_name = format!(
                "{}{}{}",
                self_display_name,
                if !self_display_name.is_empty() {
                    "-"
                } else {
                    ""
                },
                &*sc.name
            );
            debug!(
                "Command::_build_subcommand Setting display_name of {} to {:?}",
                sc.name, display_name
            );
            sc.display_name = Some(display_name);
        }

        // Ensure all args are built and ready to parse
        sc._build_self(false);

        Some(sc)
    }

    fn _build_bin_names_internal(&mut self) {
        debug!("Command::_build_bin_names");

        if !self.is_set(AppSettings::BinNameBuilt) {
            let mut mid_string = String::from(" ");
            #[cfg(feature = "usage")]
            if !self.is_subcommand_negates_reqs_set()
                && !self.is_args_conflicts_with_subcommands_set()
            {
                let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

                for s in &reqs {
                    mid_string.push_str(&s.to_string());
                    mid_string.push(' ');
                }
            }
            let is_multicall_set = self.is_multicall_set();

            let self_bin_name = if is_multicall_set {
                self.bin_name.as_deref().unwrap_or("")
            } else {
                self.bin_name.as_deref().unwrap_or(&self.name)
            }
            .to_owned();

            for mut sc in &mut self.subcommands {
                debug!("Command::_build_bin_names:iter: bin_name set...");

                if sc.usage_name.is_none() {
                    use std::fmt::Write;
                    // Display subcommand name, short and long in usage
                    let mut sc_names = String::new();
                    sc_names.push_str(sc.name.as_str());
                    let mut flag_subcmd = false;
                    if let Some(l) = sc.get_long_flag() {
                        write!(sc_names, "|--{}", l).unwrap();
                        flag_subcmd = true;
                    }
                    if let Some(s) = sc.get_short_flag() {
                        write!(sc_names, "|-{}", s).unwrap();
                        flag_subcmd = true;
                    }

                    if flag_subcmd {
                        sc_names = format!("{{{}}}", sc_names);
                    }

                    let usage_name = format!("{}{}{}", self_bin_name, mid_string, sc_names);
                    debug!(
                        "Command::_build_bin_names:iter: Setting usage_name of {} to {:?}",
                        sc.name, usage_name
                    );
                    sc.usage_name = Some(usage_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing usage_name of {} ({:?})",
                        sc.name, sc.usage_name
                    );
                }

                if sc.bin_name.is_none() {
                    let bin_name = format!(
                        "{}{}{}",
                        self_bin_name,
                        if !self_bin_name.is_empty() { " " } else { "" },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting bin_name of {} to {:?}",
                        sc.name, bin_name
                    );
                    sc.bin_name = Some(bin_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing bin_name of {} ({:?})",
                        sc.name, sc.bin_name
                    );
                }

                if sc.display_name.is_none() {
                    let self_display_name = if is_multicall_set {
                        self.display_name.as_deref().unwrap_or("")
                    } else {
                        self.display_name.as_deref().unwrap_or(&self.name)
                    };
                    let display_name = format!(
                        "{}{}{}",
                        self_display_name,
                        if !self_display_name.is_empty() {
                            "-"
                        } else {
                            ""
                        },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting display_name of {} to {:?}",
                        sc.name, display_name
                    );
                    sc.display_name = Some(display_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing display_name of {} ({:?})",
                        sc.name, sc.display_name
                    );
                }

                sc._build_bin_names_internal();
            }
            self.set(AppSettings::BinNameBuilt);
        } else {
            debug!("Command::_build_bin_names: already built");
        }
    }

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

src/builder/debug_asserts.rs (line 259)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

pub fn is_next_line_help_set(&self) -> bool

Report whether Arg::next_line_help is set

Examples found in repository

src/output/help_template.rs (line 685)

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

    fn header<T: Into<String>>(&mut self, msg: T) {
        self.writer.header(msg);
    }

    fn literal<T: Into<String>>(&mut self, msg: T) {
        self.writer.literal(msg);
    }

    fn none<T: Into<String>>(&mut self, msg: T) {
        self.writer.none(msg);
    }

    fn get_spaces(&self, n: usize) -> String {
        " ".repeat(n)
    }

    fn spaces(&mut self, n: usize) {
        self.none(self.get_spaces(n));
    }
}

/// Subcommand handling
impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
    /// Writes help for subcommands of a Parser Object to the wrapped stream.
    fn write_subcommands(&mut self, cmd: &Command) {
        debug!("HelpTemplate::write_subcommands");
        // The shortest an arg can legally be is 2 (i.e. '-x')
        let mut longest = 2;
        let mut ord_v = Vec::new();
        for subcommand in cmd
            .get_subcommands()
            .filter(|subcommand| should_show_subcommand(subcommand))
        {
            let mut styled = StyledStr::new();
            styled.literal(subcommand.get_name());
            if let Some(short) = subcommand.get_short_flag() {
                styled.none(", ");
                styled.literal(format!("-{}", short));
            }
            if let Some(long) = subcommand.get_long_flag() {
                styled.none(", ");
                styled.literal(format!("--{}", long));
            }
            longest = longest.max(styled.display_width());
            ord_v.push((subcommand.get_display_order(), styled, subcommand));
        }
        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));

        debug!("HelpTemplate::write_subcommands longest = {}", longest);

        let next_line_help = self.will_subcommands_wrap(cmd.get_subcommands(), longest);

        let mut first = true;
        for (_, sc_str, sc) in ord_v {
            if first {
                first = false;
            } else {
                self.none("\n");
            }
            self.write_subcommand(sc_str, sc, next_line_help, longest);
        }
    }

    /// Will use next line help on writing subcommands.
    fn will_subcommands_wrap<'a>(
        &self,
        subcommands: impl IntoIterator<Item = &'a Command>,
        longest: usize,
    ) -> bool {
        subcommands
            .into_iter()
            .filter(|&subcommand| should_show_subcommand(subcommand))
            .any(|subcommand| {
                let spec_vals = &self.sc_spec_vals(subcommand);
                self.subcommand_next_line_help(subcommand, spec_vals, longest)
            })
    }

    fn write_subcommand(
        &mut self,
        sc_str: StyledStr,
        cmd: &Command,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::write_subcommand");

        let spec_vals = &self.sc_spec_vals(cmd);

        let about = cmd
            .get_about()
            .or_else(|| cmd.get_long_about())
            .unwrap_or_default();

        self.subcmd(sc_str, next_line_help, longest);
        self.help(None, about, spec_vals, next_line_help, longest)
    }

    fn sc_spec_vals(&self, a: &Command) -> String {
        debug!("HelpTemplate::sc_spec_vals: a={}", a.get_name());
        let mut spec_vals = vec![];

        let mut short_als = a
            .get_visible_short_flag_aliases()
            .map(|a| format!("-{}", a))
            .collect::<Vec<_>>();
        let als = a.get_visible_aliases().map(|s| s.to_string());
        short_als.extend(als);
        let all_als = short_als.join(", ");
        if !all_als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found aliases...{:?}",
                a.get_all_aliases().collect::<Vec<_>>()
            );
            debug!(
                "HelpTemplate::spec_vals: Found short flag aliases...{:?}",
                a.get_all_short_flag_aliases().collect::<Vec<_>>()
            );
            spec_vals.push(format!("[aliases: {}]", all_als));
        }

        spec_vals.join(" ")
    }

    fn subcommand_next_line_help(&self, cmd: &Command, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help | self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = cmd.get_about().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = longest + TAB_WIDTH * 2;
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    /// Writes subcommand to the wrapped stream.
    fn subcmd(&mut self, sc_str: StyledStr, next_line_help: bool, longest: usize) {
        let width = sc_str.display_width();

        self.none(TAB);
        self.writer.extend(sc_str.into_iter());
        if !next_line_help {
            self.spaces(longest + TAB_WIDTH - width);
        }
    }
}

const NEXT_LINE_INDENT: &str = "        ";

type ArgSortKey = fn(arg: &Arg) -> (usize, String);

fn positional_sort_key(arg: &Arg) -> (usize, String) {
    (arg.get_index().unwrap_or(0), String::new())
}

fn option_sort_key(arg: &Arg) -> (usize, String) {
    // Formatting key like this to ensure that:
    // 1. Argument has long flags are printed just after short flags.
    // 2. For two args both have short flags like `-c` and `-C`, the
    //    `-C` arg is printed just after the `-c` arg
    // 3. For args without short or long flag, print them at last(sorted
    //    by arg name).
    // Example order: -a, -b, -B, -s, --select-file, --select-folder, -x

    let key = if let Some(x) = arg.get_short() {
        let mut s = x.to_ascii_lowercase().to_string();
        s.push(if x.is_ascii_lowercase() { '0' } else { '1' });
        s
    } else if let Some(x) = arg.get_long() {
        x.to_string()
    } else {
        let mut s = '{'.to_string();
        s.push_str(arg.get_id().as_str());
        s
    };
    (arg.get_display_order(), key)
}

pub(crate) fn dimensions() -> (Option<usize>, Option<usize>) {
    #[cfg(not(feature = "wrap_help"))]
    return (None, None);

    #[cfg(feature = "wrap_help")]
    terminal_size::terminal_size()
        .map(|(w, h)| (Some(w.0.into()), Some(h.0.into())))
        .unwrap_or_else(|| (parse_env("COLUMNS"), parse_env("LINES")))
}

#[cfg(feature = "wrap_help")]
fn parse_env(var: &str) -> Option<usize> {
    some!(some!(std::env::var_os(var)).to_str())
        .parse::<usize>()
        .ok()
}

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

pub fn is_hide_set(&self) -> bool

Report whether Arg::hide is set

Examples found in repository

src/output/help_template.rs (line 1005)

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

src/parser/validator.rs (line 203)

    fn build_conflict_err_usage(
        &self,
        matcher: &ArgMatcher,
        conflicting_keys: &[Id],
    ) -> Option<StyledStr> {
        let used_filtered: Vec<Id> = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .filter(|n| {
                // Filter out the args we don't want to specify.
                self.cmd.find(n).map_or(false, |a| !a.is_hide_set())
            })
            .filter(|key| !conflicting_keys.contains(key))
            .cloned()
            .collect();
        let required: Vec<Id> = used_filtered
            .iter()
            .filter_map(|key| self.cmd.find(key))
            .flat_map(|arg| arg.requires.iter().map(|item| &item.1))
            .filter(|key| !used_filtered.contains(key) && !conflicting_keys.contains(key))
            .chain(used_filtered.iter())
            .cloned()
            .collect();
        Usage::new(self.cmd)
            .required(&self.required)
            .create_usage_with_title(&required)
    }

    fn gather_requires(&mut self, matcher: &ArgMatcher) {
        debug!("Validator::gather_requires");
        for name in matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
        {
            debug!("Validator::gather_requires:iter:{:?}", name);
            if let Some(arg) = self.cmd.find(name) {
                let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                    let required = matcher.check_explicit(arg.get_id(), val);
                    required.then(|| req_arg.clone())
                };

                for req in self.cmd.unroll_arg_requires(is_relevant, arg.get_id()) {
                    self.required.insert(req);
                }
            } else if let Some(g) = self.cmd.find_group(name) {
                debug!("Validator::gather_requires:iter:{:?}:group", name);
                for r in &g.requires {
                    self.required.insert(r.clone());
                }
            }
        }
    }

    fn validate_required(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_required: required={:?}", self.required);
        self.gather_requires(matcher);

        let mut missing_required = Vec::new();
        let mut highest_index = 0;

        let is_exclusive_present = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .any(|id| {
                self.cmd
                    .find(id)
                    .map(|arg| arg.is_exclusive_set())
                    .unwrap_or_default()
            });
        debug!(
            "Validator::validate_required: is_exclusive_present={}",
            is_exclusive_present
        );

        for arg_or_group in self
            .required
            .iter()
            .filter(|r| !matcher.check_explicit(r, &ArgPredicate::IsPresent))
        {
            debug!("Validator::validate_required:iter:aog={:?}", arg_or_group);
            if let Some(arg) = self.cmd.find(arg_or_group) {
                debug!("Validator::validate_required:iter: This is an arg");
                if !is_exclusive_present && !self.is_missing_required_ok(arg, matcher, conflicts) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        arg.get_id()
                    );
                    missing_required.push(arg.get_id().clone());
                    if !arg.is_last_set() {
                        highest_index = highest_index.max(arg.get_index().unwrap_or(0));
                    }
                }
            } else if let Some(group) = self.cmd.find_group(arg_or_group) {
                debug!("Validator::validate_required:iter: This is a group");
                if !self
                    .cmd
                    .unroll_args_in_group(&group.id)
                    .iter()
                    .any(|a| matcher.check_explicit(a, &ArgPredicate::IsPresent))
                {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        group.get_id()
                    );
                    missing_required.push(group.get_id().clone());
                }
            }
        }

        // Validate the conditionally required args
        for a in self
            .cmd
            .get_arguments()
            .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
        {
            let mut required = false;

            for (other, val) in &a.r_ifs {
                if matcher.check_explicit(other, &ArgPredicate::Equals(val.into())) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        a.get_id()
                    );
                    required = true;
                }
            }

            let match_all = a.r_ifs_all.iter().all(|(other, val)| {
                matcher.check_explicit(other, &ArgPredicate::Equals(val.into()))
            });
            if match_all && !a.r_ifs_all.is_empty() {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if (!a.r_unless.is_empty() || !a.r_unless_all.is_empty())
                && self.fails_arg_required_unless(a, matcher)
            {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if required {
                missing_required.push(a.get_id().clone());
                if !a.is_last_set() {
                    highest_index = highest_index.max(a.get_index().unwrap_or(0));
                }
            }
        }

        // For display purposes, include all of the preceding positional arguments
        if !self.cmd.is_allow_missing_positional_set() {
            for pos in self
                .cmd
                .get_positionals()
                .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
            {
                if pos.get_index() < Some(highest_index) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        pos.get_id()
                    );
                    missing_required.push(pos.get_id().clone());
                }
            }
        }

        if !missing_required.is_empty() {
            ok!(self.missing_required_error(matcher, missing_required));
        }

        Ok(())
    }

    fn is_missing_required_ok(
        &self,
        a: &Arg,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> bool {
        debug!("Validator::is_missing_required_ok: {}", a.get_id());
        let conflicts = conflicts.gather_conflicts(self.cmd, matcher, a.get_id());
        !conflicts.is_empty()
    }

    // Failing a required unless means, the arg's "unless" wasn't present, and neither were they
    fn fails_arg_required_unless(&self, a: &Arg, matcher: &ArgMatcher) -> bool {
        debug!("Validator::fails_arg_required_unless: a={:?}", a.get_id());
        let exists = |id| matcher.check_explicit(id, &ArgPredicate::IsPresent);

        (a.r_unless_all.is_empty() || !a.r_unless_all.iter().all(exists))
            && !a.r_unless.iter().any(exists)
    }

    // `req_args`: an arg to include in the error even if not used
    fn missing_required_error(
        &self,
        matcher: &ArgMatcher,
        raw_req_args: Vec<Id>,
    ) -> ClapResult<()> {
        debug!("Validator::missing_required_error; incl={:?}", raw_req_args);
        debug!(
            "Validator::missing_required_error: reqs={:?}",
            self.required
        );

        let usg = Usage::new(self.cmd).required(&self.required);

        let req_args = {
            #[cfg(feature = "usage")]
            {
                usg.get_required_usage_from(&raw_req_args, Some(matcher), true)
                    .into_iter()
                    .map(|s| s.to_string())
                    .collect::<Vec<_>>()
            }

            #[cfg(not(feature = "usage"))]
            {
                raw_req_args
                    .iter()
                    .map(|id| {
                        if let Some(arg) = self.cmd.find(id) {
                            arg.to_string()
                        } else if let Some(_group) = self.cmd.find_group(id) {
                            self.cmd.format_group(id).to_string()
                        } else {
                            debug_assert!(false, "id={:?} is unknown", id);
                            "".to_owned()
                        }
                    })
                    .collect::<Vec<_>>()
            }
        };

        debug!(
            "Validator::missing_required_error: req_args={:#?}",
            req_args
        );

        let used: Vec<Id> = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .filter(|n| {
                // Filter out the args we don't want to specify.
                self.cmd.find(n).map_or(false, |a| !a.is_hide_set())
            })
            .cloned()
            .chain(raw_req_args)
            .collect();

        Err(Error::missing_required_argument(
            self.cmd,
            req_args,
            usg.create_usage_with_title(&used),
        ))
    }

src/output/usage.rs (line 165)

    fn needs_options_tag(&self) -> bool {
        debug!("Usage::needs_options_tag");
        'outer: for f in self.cmd.get_non_positionals() {
            debug!("Usage::needs_options_tag:iter: f={}", f.get_id());

            // Don't print `[OPTIONS]` just for help or version
            if f.get_long() == Some("help") || f.get_long() == Some("version") {
                debug!("Usage::needs_options_tag:iter Option is built-in");
                continue;
            }

            if f.is_hide_set() {
                debug!("Usage::needs_options_tag:iter Option is hidden");
                continue;
            }
            if f.is_required_set() {
                debug!("Usage::needs_options_tag:iter Option is required");
                continue;
            }
            for grp_s in self.cmd.groups_for_arg(f.get_id()) {
                debug!("Usage::needs_options_tag:iter:iter: grp_s={:?}", grp_s);
                if self.cmd.get_groups().any(|g| g.id == grp_s && g.required) {
                    debug!("Usage::needs_options_tag:iter:iter: Group is required");
                    continue 'outer;
                }
            }

            debug!("Usage::needs_options_tag:iter: [OPTIONS] required");
            return true;
        }

        debug!("Usage::needs_options_tag: [OPTIONS] not required");
        false
    }

    // Returns the required args in usage string form by fully unrolling all groups
    pub(crate) fn write_args(&self, incls: &[Id], force_optional: bool, styled: &mut StyledStr) {
        for required in self.get_args(incls, force_optional) {
            styled.none(" ");
            styled.extend(required.into_iter());
        }
    }

    pub(crate) fn get_args(&self, incls: &[Id], force_optional: bool) -> Vec<StyledStr> {
        debug!("Usage::get_args: incls={:?}", incls,);

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => false,
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!("Usage::get_args: unrolled_reqs={:?}", unrolled_reqs);

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let stylized = arg.stylized(Some(!force_optional));
                if let Some(index) = arg.get_index() {
                    let new_len = index + 1;
                    if required_positionals.len() < new_len {
                        required_positionals.resize(new_len, None);
                    }
                    required_positionals[index] = Some(stylized);
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        for pos in self.cmd.get_positionals() {
            if pos.is_hide_set() {
                continue;
            }
            if required_groups_members.contains(pos.get_id()) {
                continue;
            }

            let index = pos.get_index().unwrap();
            let new_len = index + 1;
            if required_positionals.len() < new_len {
                required_positionals.resize(new_len, None);
            }
            if required_positionals[index].is_some() {
                if pos.is_last_set() {
                    let styled = required_positionals[index].take().unwrap();
                    let mut new = StyledStr::new();
                    new.literal("-- ");
                    new.extend(styled.into_iter());
                    required_positionals[index] = Some(new);
                }
            } else {
                let mut styled;
                if pos.is_last_set() {
                    styled = StyledStr::new();
                    styled.literal("[-- ");
                    styled.extend(pos.stylized(Some(true)).into_iter());
                    styled.literal("]");
                } else {
                    styled = pos.stylized(Some(false));
                }
                required_positionals[index] = Some(styled);
            }
            if pos.is_last_set() && force_optional {
                required_positionals[index] = None;
            }
        }

        let mut ret_val = Vec::new();
        if !force_optional {
            ret_val.extend(required_opts);
            ret_val.extend(required_groups);
        }
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_args: ret_val={:?}", ret_val);
        ret_val
    }

src/parser/parser.rs (line 798)

    fn parse_long_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        long_arg: Result<&str, &RawOsStr>,
        long_value: Option<&RawOsStr>,
        parse_state: &ParseState,
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        // maybe here lifetime should be 'a
        debug!("Parser::parse_long_arg");

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
            self.cmd[opt].is_allow_hyphen_values_set())
        {
            debug!("Parser::parse_long_arg: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        }

        debug!("Parser::parse_long_arg: Does it contain '='...");
        let long_arg = match long_arg {
            Ok(long_arg) => long_arg,
            Err(long_arg) => {
                return Ok(ParseResult::NoMatchingArg {
                    arg: long_arg.to_str_lossy().into_owned(),
                });
            }
        };
        if long_arg.is_empty() {
            debug_assert!(
                long_value.is_some(),
                "`--` should be filtered out before this point"
            );
        }

        let arg = if let Some(arg) = self.cmd.get_keymap().get(long_arg) {
            debug!("Parser::parse_long_arg: Found valid arg or flag '{}'", arg);
            Some((long_arg, arg))
        } else if self.cmd.is_infer_long_args_set() {
            self.cmd.get_arguments().find_map(|a| {
                if let Some(long) = a.get_long() {
                    if long.starts_with(long_arg) {
                        return Some((long, a));
                    }
                }
                a.aliases
                    .iter()
                    .find_map(|(alias, _)| alias.starts_with(long_arg).then(|| (alias.as_str(), a)))
            })
        } else {
            None
        };

        if let Some((_long_arg, arg)) = arg {
            let ident = Identifier::Long;
            *valid_arg_found = true;
            if arg.is_takes_value_set() {
                debug!(
                    "Parser::parse_long_arg({:?}): Found an arg with value '{:?}'",
                    long_arg, &long_value
                );
                let has_eq = long_value.is_some();
                self.parse_opt_value(ident, long_value, arg, matcher, has_eq)
            } else if let Some(rest) = long_value {
                let required = self.cmd.required_graph();
                debug!(
                    "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                    long_arg, rest
                );
                let mut used: Vec<Id> = matcher
                    .arg_ids()
                    .filter(|arg_id| {
                        matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    })
                    .filter(|&n| {
                        self.cmd.find(n).map_or(true, |a| {
                            !(a.is_hide_set() || required.contains(a.get_id()))
                        })
                    })
                    .cloned()
                    .collect();
                used.push(arg.get_id().clone());

                Ok(ParseResult::UnneededAttachedValue {
                    rest: rest.to_str_lossy().into_owned(),
                    used,
                    arg: arg.to_string(),
                })
            } else {
                debug!("Parser::parse_long_arg({:?}): Presence validated", long_arg);
                let trailing_idx = None;
                self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    vec![],
                    trailing_idx,
                    matcher,
                )
            }
        } else if let Some(sc_name) = self.possible_long_flag_subcommand(long_arg) {
            Ok(ParseResult::FlagSubCommand(sc_name.to_string()))
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
        {
            debug!(
                "Parser::parse_long_args: positional at {} allows hyphens",
                pos_counter
            );
            Ok(ParseResult::MaybeHyphenValue)
        } else {
            Ok(ParseResult::NoMatchingArg {
                arg: long_arg.to_owned(),
            })
        }
    }

    fn parse_short_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        mut short_arg: clap_lex::ShortFlags<'_>,
        parse_state: &ParseState,
        // change this to possible pos_arg when removing the usage of &mut Parser.
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        debug!("Parser::parse_short_arg: short_arg={:?}", short_arg);

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt)
                if self.cmd[opt].is_allow_hyphen_values_set() || (self.cmd[opt].is_allow_negative_numbers_set() && short_arg.is_number()))
        {
            debug!("Parser::parse_short_args: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| arg.is_allow_negative_numbers_set())
            && short_arg.is_number()
        {
            debug!("Parser::parse_short_arg: negative number");
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
            && short_arg
                .clone()
                .any(|c| !c.map(|c| self.cmd.contains_short(c)).unwrap_or_default())
        {
            debug!(
                "Parser::parse_short_args: positional at {} allows hyphens",
                pos_counter
            );
            return Ok(ParseResult::MaybeHyphenValue);
        }

        let mut ret = ParseResult::NoArg;

        let skip = self.flag_subcmd_skip;
        self.flag_subcmd_skip = 0;
        let res = short_arg.advance_by(skip);
        debug_assert_eq!(
            res,
            Ok(()),
            "tracking of `flag_subcmd_skip` is off for `{:?}`",
            short_arg
        );
        while let Some(c) = short_arg.next_flag() {
            let c = match c {
                Ok(c) => c,
                Err(rest) => {
                    return Ok(ParseResult::NoMatchingArg {
                        arg: format!("-{}", rest.to_str_lossy()),
                    });
                }
            };
            debug!("Parser::parse_short_arg:iter:{}", c);

            // Check for matching short options, and return the name if there is no trailing
            // concatenated value: -oval
            // Option: -o
            // Value: val
            if let Some(arg) = self.cmd.get_keymap().get(&c) {
                let ident = Identifier::Short;
                debug!(
                    "Parser::parse_short_arg:iter:{}: Found valid opt or flag",
                    c
                );
                *valid_arg_found = true;
                if !arg.is_takes_value_set() {
                    let arg_values = Vec::new();
                    let trailing_idx = None;
                    ret = ok!(self.react(
                        Some(ident),
                        ValueSource::CommandLine,
                        arg,
                        arg_values,
                        trailing_idx,
                        matcher,
                    ));
                    continue;
                }

                // Check for trailing concatenated value
                //
                // Cloning the iterator, so we rollback if it isn't there.
                let val = short_arg.clone().next_value_os().unwrap_or_default();
                debug!(
                    "Parser::parse_short_arg:iter:{}: val={:?} (bytes), val={:?} (ascii), short_arg={:?}",
                    c, val, val.as_raw_bytes(), short_arg
                );
                let val = Some(val).filter(|v| !v.is_empty());

                // Default to "we're expecting a value later".
                //
                // If attached value is not consumed, we may have more short
                // flags to parse, continue.
                //
                // e.g. `-xvf`, when require_equals && x.min_vals == 0, we don't
                // consume the `vf`, even if it's provided as value.
                let (val, has_eq) = if let Some(val) = val.and_then(|v| v.strip_prefix('=')) {
                    (Some(val), true)
                } else {
                    (val, false)
                };
                match ok!(self.parse_opt_value(ident, val, arg, matcher, has_eq)) {
                    ParseResult::AttachedValueNotConsumed => continue,
                    x => return Ok(x),
                }
            }

            return if let Some(sc_name) = self.cmd.find_short_subcmd(c) {
                debug!("Parser::parse_short_arg:iter:{}: subcommand={}", c, sc_name);
                // Make sure indices get updated before reading `self.cur_idx`
                ok!(self.resolve_pending(matcher));
                self.cur_idx.set(self.cur_idx.get() + 1);
                debug!("Parser::parse_short_arg: cur_idx:={}", self.cur_idx.get());

                let name = sc_name.to_string();
                // Get the index of the previously saved flag subcommand in the group of flags (if exists).
                // If it is a new flag subcommand, then the formentioned index should be the current one
                // (ie. `cur_idx`), and should be registered.
                let cur_idx = self.cur_idx.get();
                self.flag_subcmd_at.get_or_insert(cur_idx);
                let done_short_args = short_arg.is_empty();
                if done_short_args {
                    self.flag_subcmd_at = None;
                }
                Ok(ParseResult::FlagSubCommand(name))
            } else {
                Ok(ParseResult::NoMatchingArg {
                    arg: format!("-{}", c),
                })
            };
        }
        Ok(ret)
    }

    fn parse_opt_value(
        &self,
        ident: Identifier,
        attached_value: Option<&RawOsStr>,
        arg: &Arg,
        matcher: &mut ArgMatcher,
        has_eq: bool,
    ) -> ClapResult<ParseResult> {
        debug!(
            "Parser::parse_opt_value; arg={}, val={:?}, has_eq={:?}",
            arg.get_id(),
            attached_value,
            has_eq
        );
        debug!("Parser::parse_opt_value; arg.settings={:?}", arg.settings);

        debug!("Parser::parse_opt_value; Checking for val...");
        // require_equals is set, but no '=' is provided, try throwing error.
        if arg.is_require_equals_set() && !has_eq {
            if arg.get_min_vals() == 0 {
                debug!("Requires equals, but min_vals == 0");
                let arg_values = Vec::new();
                let trailing_idx = None;
                let react_result = ok!(self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    arg_values,
                    trailing_idx,
                    matcher,
                ));
                debug_assert_eq!(react_result, ParseResult::ValuesDone);
                if attached_value.is_some() {
                    Ok(ParseResult::AttachedValueNotConsumed)
                } else {
                    Ok(ParseResult::ValuesDone)
                }
            } else {
                debug!("Requires equals but not provided. Error.");
                Ok(ParseResult::EqualsNotProvided {
                    arg: arg.to_string(),
                })
            }
        } else if let Some(v) = attached_value {
            let arg_values = vec![v.to_os_str().into_owned()];
            let trailing_idx = None;
            let react_result = ok!(self.react(
                Some(ident),
                ValueSource::CommandLine,
                arg,
                arg_values,
                trailing_idx,
                matcher,
            ));
            debug_assert_eq!(react_result, ParseResult::ValuesDone);
            // Attached are always done
            Ok(ParseResult::ValuesDone)
        } else {
            debug!("Parser::parse_opt_value: More arg vals required...");
            ok!(self.resolve_pending(matcher));
            let trailing_values = false;
            matcher.pending_values_mut(arg.get_id(), Some(ident), trailing_values);
            Ok(ParseResult::Opt(arg.get_id().clone()))
        }
    }

    fn check_terminator(&self, arg: &Arg, val: &RawOsStr) -> Option<ParseResult> {
        if Some(val)
            == arg
                .terminator
                .as_ref()
                .map(|s| RawOsStr::from_str(s.as_str()))
        {
            debug!("Parser::check_terminator: terminator={:?}", arg.terminator);
            Some(ParseResult::ValuesDone)
        } else {
            None
        }
    }

    fn push_arg_values(
        &self,
        arg: &Arg,
        raw_vals: Vec<OsString>,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<()> {
        debug!("Parser::push_arg_values: {:?}", raw_vals);

        for raw_val in raw_vals {
            // update the current index because each value is a distinct index to clap
            self.cur_idx.set(self.cur_idx.get() + 1);
            debug!(
                "Parser::add_single_val_to_arg: cur_idx:={}",
                self.cur_idx.get()
            );
            let value_parser = arg.get_value_parser();
            let val = ok!(value_parser.parse_ref(self.cmd, Some(arg), &raw_val));

            matcher.add_val_to(arg.get_id(), val, raw_val);
            matcher.add_index_to(arg.get_id(), self.cur_idx.get());
        }

        Ok(())
    }

    fn resolve_pending(&self, matcher: &mut ArgMatcher) -> ClapResult<()> {
        let pending = match matcher.take_pending() {
            Some(pending) => pending,
            None => {
                return Ok(());
            }
        };

        debug!("Parser::resolve_pending: id={:?}", pending.id);
        let arg = self.cmd.find(&pending.id).expect(INTERNAL_ERROR_MSG);
        let _ = ok!(self.react(
            pending.ident,
            ValueSource::CommandLine,
            arg,
            pending.raw_vals,
            pending.trailing_idx,
            matcher,
        ));

        Ok(())
    }

    fn react(
        &self,
        ident: Option<Identifier>,
        source: ValueSource,
        arg: &Arg,
        mut raw_vals: Vec<OsString>,
        mut trailing_idx: Option<usize>,
        matcher: &mut ArgMatcher,
    ) -> ClapResult<ParseResult> {
        ok!(self.resolve_pending(matcher));

        debug!(
            "Parser::react action={:?}, identifier={:?}, source={:?}",
            arg.get_action(),
            ident,
            source
        );

        // Process before `default_missing_values` to avoid it counting as values from the command
        // line
        if source == ValueSource::CommandLine {
            ok!(self.verify_num_args(arg, &raw_vals));
        }

        if raw_vals.is_empty() {
            // We assume this case is valid: require equals, but min_vals == 0.
            if !arg.default_missing_vals.is_empty() {
                debug!("Parser::react: has default_missing_vals");
                trailing_idx = None;
                raw_vals.extend(
                    arg.default_missing_vals
                        .iter()
                        .map(|s| s.as_os_str().to_owned()),
                );
            }
        }

        if let Some(val_delim) = arg.get_value_delimiter() {
            if self.cmd.is_dont_delimit_trailing_values_set() && trailing_idx == Some(0) {
                // Nothing to do
            } else {
                let mut split_raw_vals = Vec::with_capacity(raw_vals.len());
                for (i, raw_val) in raw_vals.into_iter().enumerate() {
                    let raw_val = RawOsString::new(raw_val);
                    if !raw_val.contains(val_delim)
                        || (self.cmd.is_dont_delimit_trailing_values_set()
                            && trailing_idx == Some(i))
                    {
                        split_raw_vals.push(raw_val.into_os_string());
                    } else {
                        split_raw_vals
                            .extend(raw_val.split(val_delim).map(|x| x.to_os_str().into_owned()));
                    }
                }
                raw_vals = split_raw_vals
            }
        }

        match arg.get_action() {
            ArgAction::Set => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Append => {
                if source == ValueSource::CommandLine
                    && matches!(ident, Some(Identifier::Short) | Some(Identifier::Long))
                {
                    // Record flag's index
                    self.cur_idx.set(self.cur_idx.get() + 1);
                    debug!("Parser::react: cur_idx:={}", self.cur_idx.get());
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                if cfg!(debug_assertions) && matcher.needs_more_vals(arg) {
                    debug!(
                        "Parser::react not enough values passed in, leaving it to the validator to complain",
                    );
                }
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetTrue => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("true")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::SetFalse => {
                let raw_vals = if raw_vals.is_empty() {
                    vec![OsString::from("false")]
                } else {
                    raw_vals
                };

                if matcher.remove(arg.get_id())
                    && !(self.cmd.is_args_override_self() || arg.overrides.contains(arg.get_id()))
                {
                    return Err(ClapError::argument_conflict(
                        self.cmd,
                        arg.to_string(),
                        vec![arg.to_string()],
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Count => {
                let raw_vals = if raw_vals.is_empty() {
                    let existing_value = *matcher
                        .get_one::<crate::builder::CountType>(arg.get_id().as_str())
                        .unwrap_or(&0);
                    let next_value = existing_value.saturating_add(1);
                    vec![OsString::from(next_value.to_string())]
                } else {
                    raw_vals
                };

                matcher.remove(arg.get_id());
                self.start_custom_arg(matcher, arg, source);
                ok!(self.push_arg_values(arg, raw_vals, matcher));
                Ok(ParseResult::ValuesDone)
            }
            ArgAction::Help => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Help: use_long={}", use_long);
                Err(self.help_err(use_long))
            }
            ArgAction::Version => {
                let use_long = match ident {
                    Some(Identifier::Long) => true,
                    Some(Identifier::Short) => false,
                    Some(Identifier::Index) => true,
                    None => true,
                };
                debug!("Version: use_long={}", use_long);
                Err(self.version_err(use_long))
            }
        }
    }

    fn verify_num_args(&self, arg: &Arg, raw_vals: &[OsString]) -> ClapResult<()> {
        if self.cmd.is_ignore_errors_set() {
            return Ok(());
        }

        let actual = raw_vals.len();
        let expected = arg.get_num_args().expect(INTERNAL_ERROR_MSG);

        if 0 < expected.min_values() && actual == 0 {
            // Issue 665 (https://github.com/clap-rs/clap/issues/665)
            // Issue 1105 (https://github.com/clap-rs/clap/issues/1105)
            return Err(ClapError::empty_value(
                self.cmd,
                &super::get_possible_values_cli(arg)
                    .iter()
                    .filter(|pv| !pv.is_hide_set())
                    .map(|n| n.get_name().to_owned())
                    .collect::<Vec<_>>(),
                arg.to_string(),
            ));
        } else if let Some(expected) = expected.num_values() {
            if expected != actual {
                debug!("Validator::validate_arg_num_vals: Sending error WrongNumberOfValues");
                return Err(ClapError::wrong_number_of_values(
                    self.cmd,
                    arg.to_string(),
                    expected,
                    actual,
                    Usage::new(self.cmd).create_usage_with_title(&[]),
                ));
            }
        } else if actual < expected.min_values() {
            return Err(ClapError::too_few_values(
                self.cmd,
                arg.to_string(),
                expected.min_values(),
                actual,
                Usage::new(self.cmd).create_usage_with_title(&[]),
            ));
        } else if expected.max_values() < actual {
            debug!("Validator::validate_arg_num_vals: Sending error TooManyValues");
            return Err(ClapError::too_many_values(
                self.cmd,
                raw_vals
                    .last()
                    .expect(INTERNAL_ERROR_MSG)
                    .to_string_lossy()
                    .into_owned(),
                arg.to_string(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            ));
        }

        Ok(())
    }

    fn remove_overrides(&self, arg: &Arg, matcher: &mut ArgMatcher) {
        debug!("Parser::remove_overrides: id={:?}", arg.id);
        for override_id in &arg.overrides {
            debug!("Parser::remove_overrides:iter:{:?}: removing", override_id);
            matcher.remove(override_id);
        }

        // Override anything that can override us
        let mut transitive = Vec::new();
        for arg_id in matcher.arg_ids() {
            if let Some(overrider) = self.cmd.find(arg_id) {
                if overrider.overrides.contains(arg.get_id()) {
                    transitive.push(overrider.get_id());
                }
            }
        }
        for overrider_id in transitive {
            debug!("Parser::remove_overrides:iter:{:?}: removing", overrider_id);
            matcher.remove(overrider_id);
        }
    }

    #[cfg(feature = "env")]
    fn add_env(&mut self, matcher: &mut ArgMatcher) -> ClapResult<()> {
        debug!("Parser::add_env");

        for arg in self.cmd.get_arguments() {
            // Use env only if the arg was absent among command line args,
            // early return if this is not the case.
            if matcher.contains(&arg.id) {
                debug!("Parser::add_env: Skipping existing arg `{}`", arg);
                continue;
            }

            debug!("Parser::add_env: Checking arg `{}`", arg);
            if let Some((_, Some(ref val))) = arg.env {
                debug!("Parser::add_env: Found an opt with value={:?}", val);
                let arg_values = vec![val.to_owned()];
                let trailing_idx = None;
                let _ = ok!(self.react(
                    None,
                    ValueSource::EnvVariable,
                    arg,
                    arg_values,
                    trailing_idx,
                    matcher,
                ));
            }
        }

        Ok(())
    }

    fn add_defaults(&self, matcher: &mut ArgMatcher) -> ClapResult<()> {
        debug!("Parser::add_defaults");

        for arg in self.cmd.get_arguments() {
            debug!("Parser::add_defaults:iter:{}:", arg.get_id());
            ok!(self.add_default_value(arg, matcher));
        }

        Ok(())
    }

    fn add_default_value(&self, arg: &Arg, matcher: &mut ArgMatcher) -> ClapResult<()> {
        if !arg.default_vals_ifs.is_empty() {
            debug!("Parser::add_default_value: has conditional defaults");
            if !matcher.contains(arg.get_id()) {
                for (id, val, default) in arg.default_vals_ifs.iter() {
                    let add = if let Some(a) = matcher.get(id) {
                        match val {
                            crate::builder::ArgPredicate::Equals(v) => {
                                a.raw_vals_flatten().any(|value| v == value)
                            }
                            crate::builder::ArgPredicate::IsPresent => true,
                        }
                    } else {
                        false
                    };

                    if add {
                        if let Some(default) = default {
                            let arg_values = vec![default.to_os_string()];
                            let trailing_idx = None;
                            let _ = ok!(self.react(
                                None,
                                ValueSource::DefaultValue,
                                arg,
                                arg_values,
                                trailing_idx,
                                matcher,
                            ));
                        }
                        return Ok(());
                    }
                }
            }
        } else {
            debug!("Parser::add_default_value: doesn't have conditional defaults");
        }

        if !arg.default_vals.is_empty() {
            debug!(
                "Parser::add_default_value:iter:{}: has default vals",
                arg.get_id()
            );
            if matcher.contains(arg.get_id()) {
                debug!("Parser::add_default_value:iter:{}: was used", arg.get_id());
            // do nothing
            } else {
                debug!(
                    "Parser::add_default_value:iter:{}: wasn't used",
                    arg.get_id()
                );
                let arg_values: Vec<_> = arg
                    .default_vals
                    .iter()
                    .map(crate::builder::OsStr::to_os_string)
                    .collect();
                let trailing_idx = None;
                let _ = ok!(self.react(
                    None,
                    ValueSource::DefaultValue,
                    arg,
                    arg_values,
                    trailing_idx,
                    matcher,
                ));
            }
        } else {
            debug!(
                "Parser::add_default_value:iter:{}: doesn't have default vals",
                arg.get_id()
            );

            // do nothing
        }

        Ok(())
    }

    fn start_custom_arg(&self, matcher: &mut ArgMatcher, arg: &Arg, source: ValueSource) {
        if source == ValueSource::CommandLine {
            // With each new occurrence, remove overrides from prior occurrences
            self.remove_overrides(arg, matcher);
        }
        matcher.start_custom_arg(arg, source);
        if source.is_explicit() {
            for group in self.cmd.groups_for_arg(arg.get_id()) {
                matcher.start_custom_group(group.clone(), source);
                matcher.add_val_to(
                    &group,
                    AnyValue::new(arg.get_id().clone()),
                    OsString::from(arg.get_id().as_str()),
                );
            }
        }
    }
}

// Error, Help, and Version Methods
impl<'cmd> Parser<'cmd> {
    /// Is only used for the long flag(which is the only one needs fuzzy searching)
    fn did_you_mean_error(
        &mut self,
        arg: &str,
        matcher: &mut ArgMatcher,
        remaining_args: &[&OsStr],
        trailing_values: bool,
    ) -> ClapError {
        debug!("Parser::did_you_mean_error: arg={}", arg);
        // Didn't match a flag or option
        let longs = self
            .cmd
            .get_keymap()
            .keys()
            .filter_map(|x| match x {
                KeyType::Long(l) => Some(l.to_string_lossy().into_owned()),
                _ => None,
            })
            .collect::<Vec<_>>();
        debug!("Parser::did_you_mean_error: longs={:?}", longs);

        let did_you_mean = suggestions::did_you_mean_flag(
            arg,
            remaining_args,
            longs.iter().map(|x| &x[..]),
            self.cmd.get_subcommands_mut(),
        );

        // Add the arg to the matches to build a proper usage string
        if let Some((name, _)) = did_you_mean.as_ref() {
            if let Some(arg) = self.cmd.get_keymap().get(&name.as_ref()) {
                self.start_custom_arg(matcher, arg, ValueSource::CommandLine);
            }
        }

        let required = self.cmd.required_graph();
        let used: Vec<Id> = matcher
            .arg_ids()
            .filter(|arg_id| {
                matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
            })
            .filter(|n| self.cmd.find(n).map_or(true, |a| !a.is_hide_set()))
            .cloned()
            .collect();

        // `did_you_mean` is a lot more likely and should cause us to skip the `--` suggestion
        //
        // In theory, this is only called for `--long`s, so we don't need to check
        let suggested_trailing_arg =
            did_you_mean.is_none() && !trailing_values && self.cmd.has_positionals();
        ClapError::unknown_argument(
            self.cmd,
            format!("--{}", arg),
            did_you_mean,
            suggested_trailing_arg,
            Usage::new(self.cmd)
                .required(&required)
                .create_usage_with_title(&used),
        )
    }

pub fn is_hide_default_value_set(&self) -> bool

Report whether Arg::hide_default_value is set

Examples found in repository

src/output/help_template.rs (line 728)

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

pub fn is_hide_possible_values_set(&self) -> bool

Report whether Arg::hide_possible_values is set

Examples found in repository

src/output/help_template.rs (line 604)

    fn help(
        &mut self,
        arg: Option<&Arg>,
        about: &StyledStr,
        spec_vals: &str,
        next_line_help: bool,
        longest: usize,
    ) {
        debug!("HelpTemplate::help");

        // Is help on next line, if so then indent
        if next_line_help {
            debug!("HelpTemplate::help: Next Line...{:?}", next_line_help);
            self.none("\n");
            self.none(TAB);
            self.none(NEXT_LINE_INDENT);
        }

        let spaces = if next_line_help {
            TAB.len() + NEXT_LINE_INDENT.len()
        } else if let Some(true) = arg.map(|a| a.is_positional()) {
            longest + TAB_WIDTH * 2
        } else {
            longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
        };
        let trailing_indent = spaces; // Don't indent any further than the first line is indented
        let trailing_indent = self.get_spaces(trailing_indent);

        let mut help = about.clone();
        replace_newline_var(&mut help);
        if !spec_vals.is_empty() {
            if !help.is_empty() {
                let sep = if self.use_long && arg.is_some() {
                    "\n\n"
                } else {
                    " "
                };
                help.none(sep);
            }
            help.none(spec_vals);
        }
        let avail_chars = self.term_w.saturating_sub(spaces);
        debug!(
            "HelpTemplate::help: help_width={}, spaces={}, avail={}",
            spaces,
            help.display_width(),
            avail_chars
        );
        help.wrap(avail_chars);
        help.indent("", &trailing_indent);
        let help_is_empty = help.is_empty();
        self.writer.extend(help.into_iter());
        if let Some(arg) = arg {
            const DASH_SPACE: usize = "- ".len();
            const COLON_SPACE: usize = ": ".len();
            let possible_vals = arg.get_possible_values();
            if self.use_long
                && !arg.is_hide_possible_values_set()
                && possible_vals.iter().any(PossibleValue::should_show_help)
            {
                debug!(
                    "HelpTemplate::help: Found possible vals...{:?}",
                    possible_vals
                );
                if !help_is_empty {
                    self.none("\n\n");
                    self.spaces(spaces);
                }
                self.none("Possible values:");
                let longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
                    .max()
                    .expect("Only called with possible value");
                let help_longest = possible_vals
                    .iter()
                    .filter_map(|f| f.get_visible_help().map(|h| h.display_width()))
                    .max()
                    .expect("Only called with possible value with help");
                // should new line
                let taken = longest + spaces + DASH_SPACE;

                let possible_value_new_line =
                    self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;

                let spaces = spaces + TAB_WIDTH - DASH_SPACE;
                let trailing_indent = if possible_value_new_line {
                    spaces + DASH_SPACE
                } else {
                    spaces + longest + DASH_SPACE + COLON_SPACE
                };
                let trailing_indent = self.get_spaces(trailing_indent);

                for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
                    self.none("\n");
                    self.spaces(spaces);
                    self.none("- ");
                    self.literal(pv.get_name());
                    if let Some(help) = pv.get_help() {
                        debug!("HelpTemplate::help: Possible Value help");

                        if possible_value_new_line {
                            self.none(":\n");
                            self.spaces(trailing_indent.len());
                        } else {
                            self.none(": ");
                            // To align help messages
                            self.spaces(longest - display_width(pv.get_name()));
                        }

                        let avail_chars = if self.term_w > trailing_indent.len() {
                            self.term_w - trailing_indent.len()
                        } else {
                            usize::MAX
                        };

                        let mut help = help.clone();
                        replace_newline_var(&mut help);
                        help.wrap(avail_chars);
                        help.indent("", &trailing_indent);
                        self.writer.extend(help.into_iter());
                    }
                }
            }
        }
    }

    /// Will use next line help on writing args.
    fn will_args_wrap(&self, args: &[&Arg], longest: usize) -> bool {
        args.iter()
            .filter(|arg| should_show_arg(self.use_long, arg))
            .any(|arg| {
                let spec_vals = &self.spec_vals(arg);
                self.arg_next_line_help(arg, spec_vals, longest)
            })
    }

    fn arg_next_line_help(&self, arg: &Arg, spec_vals: &str, longest: usize) -> bool {
        if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
            // setting_next_line
            true
        } else {
            // force_next_line
            let h = arg.get_help().unwrap_or_default();
            let h_w = h.display_width() + display_width(spec_vals);
            let taken = if arg.is_positional() {
                longest + TAB_WIDTH * 2
            } else {
                longest + TAB_WIDTH * 2 + 4 // See `fn short` for the 4
            };
            self.term_w >= taken
                && (taken as f32 / self.term_w as f32) > 0.40
                && h_w > (self.term_w - taken)
        }
    }

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

pub fn is_hide_env_set(&self) -> bool

Available on crate feature env only.

Report whether Arg::hide_env is set

Examples found in repository

src/output/help_template.rs (line 708)

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

pub fn is_hide_env_values_set(&self) -> bool

Available on crate feature env only.

Report whether Arg::hide_env_values is set

Examples found in repository

src/output/help_template.rs (line 713)

    fn spec_vals(&self, a: &Arg) -> String {
        debug!("HelpTemplate::spec_vals: a={}", a);
        let mut spec_vals = Vec::new();
        #[cfg(feature = "env")]
        if let Some(ref env) = a.env {
            if !a.is_hide_env_set() {
                debug!(
                    "HelpTemplate::spec_vals: Found environment variable...[{:?}:{:?}]",
                    env.0, env.1
                );
                let env_val = if !a.is_hide_env_values_set() {
                    format!(
                        "={}",
                        env.1
                            .as_ref()
                            .map(|s| s.to_string_lossy())
                            .unwrap_or_default()
                    )
                } else {
                    Default::default()
                };
                let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
                spec_vals.push(env_info);
            }
        }
        if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found default value...[{:?}]",
                a.default_vals
            );

            let pvs = a
                .default_vals
                .iter()
                .map(|pvs| pvs.to_string_lossy())
                .map(|pvs| {
                    if pvs.contains(char::is_whitespace) {
                        Cow::from(format!("{:?}", pvs))
                    } else {
                        pvs
                    }
                })
                .collect::<Vec<_>>()
                .join(" ");

            spec_vals.push(format!("[default: {}]", pvs));
        }

        let als = a
            .aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|als| als.0.as_str()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!("HelpTemplate::spec_vals: Found aliases...{:?}", a.aliases);
            spec_vals.push(format!("[aliases: {}]", als));
        }

        let als = a
            .short_aliases
            .iter()
            .filter(|&als| als.1) // visible
            .map(|&als| als.0.to_string()) // name
            .collect::<Vec<_>>()
            .join(", ");
        if !als.is_empty() {
            debug!(
                "HelpTemplate::spec_vals: Found short aliases...{:?}",
                a.short_aliases
            );
            spec_vals.push(format!("[short aliases: {}]", als));
        }

        let possible_vals = a.get_possible_values();
        if !(a.is_hide_possible_values_set()
            || possible_vals.is_empty()
            || self.use_long && possible_vals.iter().any(PossibleValue::should_show_help))
        {
            debug!(
                "HelpTemplate::spec_vals: Found possible vals...{:?}",
                possible_vals
            );

            let pvs = possible_vals
                .iter()
                .filter_map(PossibleValue::get_visible_quoted_name)
                .collect::<Vec<_>>()
                .join(", ");

            spec_vals.push(format!("[possible values: {}]", pvs));
        }
        let connector = if self.use_long { "\n" } else { " " };
        spec_vals.join(connector)
    }

pub fn is_hide_short_help_set(&self) -> bool

Report whether Arg::hide_short_help is set

Examples found in repository

src/output/help_template.rs (line 1009)

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

src/builder/command.rs (line 4598)

    fn long_help_exists_(&self) -> bool {
        debug!("Command::long_help_exists");
        // In this case, both must be checked. This allows the retention of
        // original formatting, but also ensures that the actual -h or --help
        // specified by the user is sent through. If hide_short_help is not included,
        // then items specified with hidden_short_help will also be hidden.
        let should_long = |v: &Arg| {
            v.get_long_help().is_some()
                || v.is_hide_long_help_set()
                || v.is_hide_short_help_set()
                || v.get_possible_values()
                    .iter()
                    .any(PossibleValue::should_show_help)
        };

        // Subcommands aren't checked because we prefer short help for them, deferring to
        // `cmd subcmd --help` for more.
        self.get_long_about().is_some()
            || self.get_before_long_help().is_some()
            || self.get_after_long_help().is_some()
            || self.get_arguments().any(should_long)
    }

pub fn is_hide_long_help_set(&self) -> bool

Report whether Arg::hide_long_help is set

Examples found in repository

src/output/help_template.rs (line 1008)

fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
    debug!(
        "should_show_arg: use_long={:?}, arg={}",
        use_long,
        arg.get_id()
    );
    if arg.is_hide_set() {
        return false;
    }
    (!arg.is_hide_long_help_set() && use_long)
        || (!arg.is_hide_short_help_set() && !use_long)
        || arg.is_next_line_help_set()
}

src/builder/command.rs (line 4597)

    fn long_help_exists_(&self) -> bool {
        debug!("Command::long_help_exists");
        // In this case, both must be checked. This allows the retention of
        // original formatting, but also ensures that the actual -h or --help
        // specified by the user is sent through. If hide_short_help is not included,
        // then items specified with hidden_short_help will also be hidden.
        let should_long = |v: &Arg| {
            v.get_long_help().is_some()
                || v.is_hide_long_help_set()
                || v.is_hide_short_help_set()
                || v.get_possible_values()
                    .iter()
                    .any(PossibleValue::should_show_help)
        };

        // Subcommands aren't checked because we prefer short help for them, deferring to
        // `cmd subcmd --help` for more.
        self.get_long_about().is_some()
            || self.get_before_long_help().is_some()
            || self.get_after_long_help().is_some()
            || self.get_arguments().any(should_long)
    }

pub fn is_require_equals_set(&self) -> bool

Report whether Arg::require_equals is set

Examples found in repository

src/builder/arg.rs (line 4154)

    pub(crate) fn stylize_arg_suffix(&self, required: Option<bool>) -> StyledStr {
        let mut styled = StyledStr::new();

        let mut need_closing_bracket = false;
        if self.is_takes_value_set() && !self.is_positional() {
            let is_optional_val = self.get_min_vals() == 0;
            if self.is_require_equals_set() {
                if is_optional_val {
                    need_closing_bracket = true;
                    styled.placeholder("[=");
                } else {
                    styled.literal("=");
                }
            } else if is_optional_val {
                need_closing_bracket = true;
                styled.placeholder(" [");
            } else {
                styled.placeholder(" ");
            }
        }
        if self.is_takes_value_set() || self.is_positional() {
            let required = required.unwrap_or_else(|| self.is_required_set());
            let arg_val = self.render_arg_val(required);
            styled.placeholder(arg_val);
        } else if matches!(*self.get_action(), ArgAction::Count) {
            styled.placeholder("...");
        }
        if need_closing_bracket {
            styled.placeholder("]");
        }

        styled
    }

src/parser/parser.rs (line 1008)

    fn parse_opt_value(
        &self,
        ident: Identifier,
        attached_value: Option<&RawOsStr>,
        arg: &Arg,
        matcher: &mut ArgMatcher,
        has_eq: bool,
    ) -> ClapResult<ParseResult> {
        debug!(
            "Parser::parse_opt_value; arg={}, val={:?}, has_eq={:?}",
            arg.get_id(),
            attached_value,
            has_eq
        );
        debug!("Parser::parse_opt_value; arg.settings={:?}", arg.settings);

        debug!("Parser::parse_opt_value; Checking for val...");
        // require_equals is set, but no '=' is provided, try throwing error.
        if arg.is_require_equals_set() && !has_eq {
            if arg.get_min_vals() == 0 {
                debug!("Requires equals, but min_vals == 0");
                let arg_values = Vec::new();
                let trailing_idx = None;
                let react_result = ok!(self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    arg_values,
                    trailing_idx,
                    matcher,
                ));
                debug_assert_eq!(react_result, ParseResult::ValuesDone);
                if attached_value.is_some() {
                    Ok(ParseResult::AttachedValueNotConsumed)
                } else {
                    Ok(ParseResult::ValuesDone)
                }
            } else {
                debug!("Requires equals but not provided. Error.");
                Ok(ParseResult::EqualsNotProvided {
                    arg: arg.to_string(),
                })
            }
        } else if let Some(v) = attached_value {
            let arg_values = vec![v.to_os_str().into_owned()];
            let trailing_idx = None;
            let react_result = ok!(self.react(
                Some(ident),
                ValueSource::CommandLine,
                arg,
                arg_values,
                trailing_idx,
                matcher,
            ));
            debug_assert_eq!(react_result, ParseResult::ValuesDone);
            // Attached are always done
            Ok(ParseResult::ValuesDone)
        } else {
            debug!("Parser::parse_opt_value: More arg vals required...");
            ok!(self.resolve_pending(matcher));
            let trailing_values = false;
            matcher.pending_values_mut(arg.get_id(), Some(ident), trailing_values);
            Ok(ParseResult::Opt(arg.get_id().clone()))
        }
    }

src/builder/debug_asserts.rs (line 786)

fn assert_arg(arg: &Arg) {
    debug!("Arg::_debug_asserts:{}", arg.get_id());

    // Self conflict
    // TODO: this check should be recursive
    assert!(
        !arg.blacklist.iter().any(|x| x == arg.get_id()),
        "Argument '{}' cannot conflict with itself",
        arg.get_id(),
    );

    assert_eq!(
        arg.get_action().takes_values(),
        arg.is_takes_value_set(),
        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
        arg.get_id(),
        arg.get_action()
    );
    if let Some(action_type_id) = arg.get_action().value_type_id() {
        assert_eq!(
            action_type_id,
            arg.get_value_parser().type_id(),
            "Argument `{}`'s selected action {:?} contradicts `value_parser` ({:?})",
            arg.get_id(),
            arg.get_action(),
            arg.get_value_parser()
        );
    }

    if arg.get_value_hint() != ValueHint::Unknown {
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}' has value hint but takes no value",
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_multiple_values_set(),
                "Argument '{}' uses hint CommandWithArguments and must accept multiple values",
                arg.get_id()
            )
        }
    }

    if arg.index.is_some() {
        assert!(
            arg.is_positional(),
            "Argument '{}' is a positional argument and can't have short or long name versions",
            arg.get_id()
        );
        assert!(
            arg.is_takes_value_set(),
            "Argument '{}` is positional, it must take a value{}",
            arg.get_id(),
            if arg.get_id() == Id::HELP {
                " (`mut_arg` no longer works with implicit `--help`)"
            } else if arg.get_id() == Id::VERSION {
                " (`mut_arg` no longer works with implicit `--version`)"
            } else {
                ""
            }
        );
    }

    let num_vals = arg.get_num_args().expect(INTERNAL_ERROR_MSG);
    // This can be the cause of later asserts, so put this first
    if num_vals != ValueRange::EMPTY {
        // HACK: Don't check for flags to make the derive easier
        let num_val_names = arg.get_value_names().unwrap_or(&[]).len();
        if num_vals.max_values() < num_val_names {
            panic!(
                "Argument {}: Too many value names ({}) compared to `num_args` ({})",
                arg.get_id(),
                num_val_names,
                num_vals
            );
        }
    }

    assert_eq!(
        num_vals.takes_values(),
        arg.is_takes_value_set(),
        "Argument {}: mismatch between `num_args` ({}) and `takes_value`",
        arg.get_id(),
        num_vals,
    );
    assert_eq!(
        num_vals.is_multiple(),
        arg.is_multiple_values_set(),
        "Argument {}: mismatch between `num_args` ({}) and `multiple_values`",
        arg.get_id(),
        num_vals,
    );

    if 1 < num_vals.min_values() {
        assert!(
            !arg.is_require_equals_set(),
            "Argument {}: cannot accept more than 1 arg (num_args={}) with require_equals",
            arg.get_id(),
            num_vals
        );
    }

    if num_vals == ValueRange::SINGLE {
        assert!(
            !arg.is_multiple_values_set(),
            "Argument {}: mismatch between `num_args` and `multiple_values`",
            arg.get_id()
        );
    }

    assert_arg_flags(arg);

    assert_defaults(arg, "default_value", arg.default_vals.iter());
    assert_defaults(
        arg,
        "default_missing_value",
        arg.default_missing_vals.iter(),
    );
    assert_defaults(
        arg,
        "default_value_if",
        arg.default_vals_ifs
            .iter()
            .filter_map(|(_, _, default)| default.as_ref()),
    );
}

pub fn is_exclusive_set(&self) -> bool

Reports whether Arg::exclusive is set

Examples found in repository

src/parser/validator.rs (line 139)

    fn validate_exclusive(&self, matcher: &ArgMatcher) -> ClapResult<()> {
        debug!("Validator::validate_exclusive");
        let args_count = matcher
            .arg_ids()
            .filter(|arg_id| {
                matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    // Avoid including our own groups by checking none of them.  If a group is present, the
                    // args for the group will be.
                    && self.cmd.find(arg_id).is_some()
            })
            .count();
        if args_count <= 1 {
            // Nothing present to conflict with
            return Ok(());
        }

        matcher
            .arg_ids()
            .filter(|arg_id| {
                matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
            })
            .filter_map(|name| {
                debug!("Validator::validate_exclusive:iter:{:?}", name);
                self.cmd
                    .find(name)
                    // Find `arg`s which are exclusive but also appear with other args.
                    .filter(|&arg| arg.is_exclusive_set() && args_count > 1)
            })
            // Throw an error for the first conflict found.
            .try_for_each(|arg| {
                Err(Error::argument_conflict(
                    self.cmd,
                    arg.to_string(),
                    Vec::new(),
                    Usage::new(self.cmd)
                        .required(&self.required)
                        .create_usage_with_title(&[]),
                ))
            })
    }

    fn build_conflict_err(
        &self,
        name: &Id,
        conflict_ids: &[Id],
        matcher: &ArgMatcher,
    ) -> ClapResult<()> {
        if conflict_ids.is_empty() {
            return Ok(());
        }

        debug!("Validator::build_conflict_err: name={:?}", name);
        let mut seen = FlatSet::new();
        let conflicts = conflict_ids
            .iter()
            .flat_map(|c_id| {
                if self.cmd.find_group(c_id).is_some() {
                    self.cmd.unroll_args_in_group(c_id)
                } else {
                    vec![c_id.clone()]
                }
            })
            .filter_map(|c_id| {
                seen.insert(c_id.clone()).then(|| {
                    let c_arg = self.cmd.find(&c_id).expect(INTERNAL_ERROR_MSG);
                    c_arg.to_string()
                })
            })
            .collect();

        let former_arg = self.cmd.find(name).expect(INTERNAL_ERROR_MSG);
        let usg = self.build_conflict_err_usage(matcher, conflict_ids);
        Err(Error::argument_conflict(
            self.cmd,
            former_arg.to_string(),
            conflicts,
            usg,
        ))
    }

    fn build_conflict_err_usage(
        &self,
        matcher: &ArgMatcher,
        conflicting_keys: &[Id],
    ) -> Option<StyledStr> {
        let used_filtered: Vec<Id> = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .filter(|n| {
                // Filter out the args we don't want to specify.
                self.cmd.find(n).map_or(false, |a| !a.is_hide_set())
            })
            .filter(|key| !conflicting_keys.contains(key))
            .cloned()
            .collect();
        let required: Vec<Id> = used_filtered
            .iter()
            .filter_map(|key| self.cmd.find(key))
            .flat_map(|arg| arg.requires.iter().map(|item| &item.1))
            .filter(|key| !used_filtered.contains(key) && !conflicting_keys.contains(key))
            .chain(used_filtered.iter())
            .cloned()
            .collect();
        Usage::new(self.cmd)
            .required(&self.required)
            .create_usage_with_title(&required)
    }

    fn gather_requires(&mut self, matcher: &ArgMatcher) {
        debug!("Validator::gather_requires");
        for name in matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
        {
            debug!("Validator::gather_requires:iter:{:?}", name);
            if let Some(arg) = self.cmd.find(name) {
                let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                    let required = matcher.check_explicit(arg.get_id(), val);
                    required.then(|| req_arg.clone())
                };

                for req in self.cmd.unroll_arg_requires(is_relevant, arg.get_id()) {
                    self.required.insert(req);
                }
            } else if let Some(g) = self.cmd.find_group(name) {
                debug!("Validator::gather_requires:iter:{:?}:group", name);
                for r in &g.requires {
                    self.required.insert(r.clone());
                }
            }
        }
    }

    fn validate_required(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_required: required={:?}", self.required);
        self.gather_requires(matcher);

        let mut missing_required = Vec::new();
        let mut highest_index = 0;

        let is_exclusive_present = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .any(|id| {
                self.cmd
                    .find(id)
                    .map(|arg| arg.is_exclusive_set())
                    .unwrap_or_default()
            });
        debug!(
            "Validator::validate_required: is_exclusive_present={}",
            is_exclusive_present
        );

        for arg_or_group in self
            .required
            .iter()
            .filter(|r| !matcher.check_explicit(r, &ArgPredicate::IsPresent))
        {
            debug!("Validator::validate_required:iter:aog={:?}", arg_or_group);
            if let Some(arg) = self.cmd.find(arg_or_group) {
                debug!("Validator::validate_required:iter: This is an arg");
                if !is_exclusive_present && !self.is_missing_required_ok(arg, matcher, conflicts) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        arg.get_id()
                    );
                    missing_required.push(arg.get_id().clone());
                    if !arg.is_last_set() {
                        highest_index = highest_index.max(arg.get_index().unwrap_or(0));
                    }
                }
            } else if let Some(group) = self.cmd.find_group(arg_or_group) {
                debug!("Validator::validate_required:iter: This is a group");
                if !self
                    .cmd
                    .unroll_args_in_group(&group.id)
                    .iter()
                    .any(|a| matcher.check_explicit(a, &ArgPredicate::IsPresent))
                {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        group.get_id()
                    );
                    missing_required.push(group.get_id().clone());
                }
            }
        }

        // Validate the conditionally required args
        for a in self
            .cmd
            .get_arguments()
            .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
        {
            let mut required = false;

            for (other, val) in &a.r_ifs {
                if matcher.check_explicit(other, &ArgPredicate::Equals(val.into())) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        a.get_id()
                    );
                    required = true;
                }
            }

            let match_all = a.r_ifs_all.iter().all(|(other, val)| {
                matcher.check_explicit(other, &ArgPredicate::Equals(val.into()))
            });
            if match_all && !a.r_ifs_all.is_empty() {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if (!a.r_unless.is_empty() || !a.r_unless_all.is_empty())
                && self.fails_arg_required_unless(a, matcher)
            {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if required {
                missing_required.push(a.get_id().clone());
                if !a.is_last_set() {
                    highest_index = highest_index.max(a.get_index().unwrap_or(0));
                }
            }
        }

        // For display purposes, include all of the preceding positional arguments
        if !self.cmd.is_allow_missing_positional_set() {
            for pos in self
                .cmd
                .get_positionals()
                .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
            {
                if pos.get_index() < Some(highest_index) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        pos.get_id()
                    );
                    missing_required.push(pos.get_id().clone());
                }
            }
        }

        if !missing_required.is_empty() {
            ok!(self.missing_required_error(matcher, missing_required));
        }

        Ok(())
    }

pub fn is_trailing_var_arg_set(&self) -> bool

Report whether Arg::trailing_var_arg is set

Examples found in repository

src/builder/debug_asserts.rs (line 274)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

src/parser/parser.rs (line 396)

    pub(crate) fn get_matches_with(
        &mut self,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        mut args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<()> {
        debug!("Parser::get_matches_with");
        // Verify all positional assertions pass

        let mut subcmd_name: Option<String> = None;
        let mut keep_state = false;
        let mut parse_state = ParseState::ValuesDone;
        let mut pos_counter = 1;

        // Already met any valid arg(then we shouldn't expect subcommands after it).
        let mut valid_arg_found = false;
        // If the user already passed '--'. Meaning only positional args follow.
        let mut trailing_values = false;

        // Count of positional args
        let positional_count = self
            .cmd
            .get_keymap()
            .keys()
            .filter(|x| x.is_position())
            .count();
        // If any arg sets .last(true)
        let contains_last = self.cmd.get_arguments().any(|x| x.is_last_set());

        while let Some(arg_os) = raw_args.next(&mut args_cursor) {
            // Recover the replaced items if any.
            if let Some(replaced_items) = arg_os
                .to_value()
                .ok()
                .and_then(|a| self.cmd.get_replacement(a))
            {
                debug!(
                    "Parser::get_matches_with: found replacer: {:?}, target: {:?}",
                    arg_os, replaced_items
                );
                raw_args.insert(&args_cursor, replaced_items);
                continue;
            }

            debug!(
                "Parser::get_matches_with: Begin parsing '{:?}' ({:?})",
                arg_os.to_value_os(),
                arg_os.to_value_os().as_raw_bytes()
            );

            // Has the user already passed '--'? Meaning only positional args follow
            if !trailing_values {
                if self.cmd.is_subcommand_precedence_over_arg_set()
                    || !matches!(parse_state, ParseState::Opt(_) | ParseState::Pos(_))
                {
                    // Does the arg match a subcommand name, or any of its aliases (if defined)
                    let sc_name = self.possible_subcommand(arg_os.to_value(), valid_arg_found);
                    debug!("Parser::get_matches_with: sc={:?}", sc_name);
                    if let Some(sc_name) = sc_name {
                        if sc_name == "help" && !self.cmd.is_disable_help_subcommand_set() {
                            ok!(self.parse_help_subcommand(raw_args.remaining(&mut args_cursor)));
                            unreachable!("`parse_help_subcommand` always errors");
                        } else {
                            subcmd_name = Some(sc_name.to_owned());
                        }
                        break;
                    }
                }

                if arg_os.is_escape() {
                    if matches!(&parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
                        self.cmd[opt].is_allow_hyphen_values_set())
                    {
                        // ParseResult::MaybeHyphenValue, do nothing
                    } else {
                        debug!("Parser::get_matches_with: setting TrailingVals=true");
                        trailing_values = true;
                        matcher.start_trailing();
                        continue;
                    }
                } else if let Some((long_arg, long_value)) = arg_os.to_long() {
                    let parse_result = ok!(self.parse_long_arg(
                        matcher,
                        long_arg,
                        long_value,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    debug!(
                        "Parser::get_matches_with: After parse_long_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            unreachable!("`to_long` always has the flag specified")
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            debug!(
                                "Parser::get_matches_with: FlagSubCommand found in long arg {:?}",
                                &name
                            );
                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            let remaining_args: Vec<_> =
                                raw_args.remaining(&mut args_cursor).collect();
                            return Err(self.did_you_mean_error(
                                &arg,
                                matcher,
                                &remaining_args,
                                trailing_values,
                            ));
                        }
                        ParseResult::UnneededAttachedValue { rest, used, arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::too_many_values(
                                self.cmd,
                                rest,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&used),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::AttachedValueNotConsumed => {
                            unreachable!()
                        }
                    }
                } else if let Some(short_arg) = arg_os.to_short() {
                    // Arg looks like a short flag, and not a possible number

                    // Try to parse short args like normal, if allow_hyphen_values or
                    // AllowNegativeNumbers is set, parse_short_arg will *not* throw
                    // an error, and instead return Ok(None)
                    let parse_result = ok!(self.parse_short_arg(
                        matcher,
                        short_arg,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    // If it's None, we then check if one of those two AppSettings was set
                    debug!(
                        "Parser::get_matches_with: After parse_short_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            // Is a single dash `-`, try positional.
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            // If there are more short flags to be processed, we should keep the state, and later
                            // revisit the current group of short flags skipping the subcommand.
                            keep_state = self
                                .flag_subcmd_at
                                .map(|at| {
                                    raw_args
                                        .seek(&mut args_cursor, clap_lex::SeekFrom::Current(-1));
                                    // Since we are now saving the current state, the number of flags to skip during state recovery should
                                    // be the current index (`cur_idx`) minus ONE UNIT TO THE LEFT of the starting position.
                                    self.flag_subcmd_skip = self.cur_idx.get() - at + 1;
                                })
                                .is_some();

                            debug!(
                                "Parser::get_matches_with:FlagSubCommandShort: subcmd_name={}, keep_state={}, flag_subcmd_skip={}",
                                name,
                                keep_state,
                                self.flag_subcmd_skip
                            );

                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            // We already know it looks like a flag
                            let suggested_trailing_arg =
                                !trailing_values && self.cmd.has_positionals();
                            return Err(ClapError::unknown_argument(
                                self.cmd,
                                arg,
                                None,
                                suggested_trailing_arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::UnneededAttachedValue { .. }
                        | ParseResult::AttachedValueNotConsumed => unreachable!(),
                    }
                }

                if let ParseState::Opt(id) = &parse_state {
                    // Assume this is a value of a previous arg.

                    // get the option so we can check the settings
                    let arg = &self.cmd[id];
                    let parse_result = if let Some(parse_result) =
                        self.check_terminator(arg, arg_os.to_value_os())
                    {
                        parse_result
                    } else {
                        let trailing_values = false;
                        let arg_values = matcher.pending_values_mut(id, None, trailing_values);
                        arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                        if matcher.needs_more_vals(arg) {
                            ParseResult::Opt(arg.get_id().clone())
                        } else {
                            ParseResult::ValuesDone
                        }
                    };
                    parse_state = match parse_result {
                        ParseResult::Opt(id) => ParseState::Opt(id),
                        ParseResult::ValuesDone => ParseState::ValuesDone,
                        _ => unreachable!(),
                    };
                    // get the next value from the iterator
                    continue;
                }
            }

            // Correct pos_counter.
            pos_counter = {
                let is_second_to_last = pos_counter + 1 == positional_count;

                // The last positional argument, or second to last positional
                // argument may be set to .multiple_values(true) or `.multiple_occurrences(true)`
                let low_index_mults = is_second_to_last
                    && self.cmd.get_positionals().any(|a| {
                        a.is_multiple() && (positional_count != a.get_index().unwrap_or(0))
                    })
                    && self
                        .cmd
                        .get_positionals()
                        .last()
                        .map_or(false, |p_name| !p_name.is_last_set());

                let missing_pos = self.cmd.is_allow_missing_positional_set()
                    && is_second_to_last
                    && !trailing_values;

                debug!(
                    "Parser::get_matches_with: Positional counter...{}",
                    pos_counter
                );
                debug!(
                    "Parser::get_matches_with: Low index multiples...{:?}",
                    low_index_mults
                );

                if low_index_mults || missing_pos {
                    let skip_current = if let Some(n) = raw_args.peek(&args_cursor) {
                        if let Some(arg) = self
                            .cmd
                            .get_positionals()
                            .find(|a| a.get_index() == Some(pos_counter))
                        {
                            // If next value looks like a new_arg or it's a
                            // subcommand, skip positional argument under current
                            // pos_counter(which means current value cannot be a
                            // positional argument with a value next to it), assume
                            // current value matches the next arg.
                            self.is_new_arg(&n, arg)
                                || self
                                    .possible_subcommand(n.to_value(), valid_arg_found)
                                    .is_some()
                        } else {
                            true
                        }
                    } else {
                        true
                    };

                    if skip_current {
                        debug!("Parser::get_matches_with: Bumping the positional counter...");
                        pos_counter + 1
                    } else {
                        pos_counter
                    }
                } else if trailing_values
                    && (self.cmd.is_allow_missing_positional_set() || contains_last)
                {
                    // Came to -- and one positional has .last(true) set, so we go immediately
                    // to the last (highest index) positional
                    debug!("Parser::get_matches_with: .last(true) and --, setting last pos");
                    positional_count
                } else {
                    pos_counter
                }
            };

            if let Some(arg) = self.cmd.get_keymap().get(&pos_counter) {
                if arg.is_last_set() && !trailing_values {
                    let _ = self.resolve_pending(matcher);
                    // Its already considered a positional, we don't need to suggest turning it
                    // into one
                    let suggested_trailing_arg = false;
                    return Err(ClapError::unknown_argument(
                        self.cmd,
                        arg_os.display().to_string(),
                        None,
                        suggested_trailing_arg,
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }

                if arg.is_trailing_var_arg_set() {
                    trailing_values = true;
                }

                if matcher.pending_arg_id() != Some(arg.get_id()) || !arg.is_multiple_values_set() {
                    ok!(self.resolve_pending(matcher));
                }
                if let Some(_parse_result) = self.check_terminator(arg, arg_os.to_value_os()) {
                    debug!(
                        "Parser::get_matches_with: ignoring terminator result {:?}",
                        _parse_result
                    );
                } else {
                    let arg_values = matcher.pending_values_mut(
                        arg.get_id(),
                        Some(Identifier::Index),
                        trailing_values,
                    );
                    arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                }

                // Only increment the positional counter if it doesn't allow multiples
                if !arg.is_multiple() {
                    pos_counter += 1;
                    parse_state = ParseState::ValuesDone;
                } else {
                    parse_state = ParseState::Pos(arg.get_id().clone());
                }
                valid_arg_found = true;
            } else if let Some(external_parser) =
                self.cmd.get_external_subcommand_value_parser().cloned()
            {
                // Get external subcommand name
                let sc_name = match arg_os.to_value() {
                    Ok(s) => s.to_owned(),
                    Err(_) => {
                        let _ = self.resolve_pending(matcher);
                        return Err(ClapError::invalid_utf8(
                            self.cmd,
                            Usage::new(self.cmd).create_usage_with_title(&[]),
                        ));
                    }
                };

                // Collect the external subcommand args
                let mut sc_m = ArgMatcher::new(self.cmd);
                sc_m.start_occurrence_of_external(self.cmd);

                for raw_val in raw_args.remaining(&mut args_cursor) {
                    let val = ok!(external_parser.parse_ref(self.cmd, None, raw_val));
                    let external_id = Id::from_static_ref(Id::EXTERNAL);
                    sc_m.add_val_to(&external_id, val, raw_val.to_os_string());
                }

                matcher.subcommand(SubCommand {
                    name: sc_name,
                    matches: sc_m.into_inner(),
                });

                ok!(self.resolve_pending(matcher));
                #[cfg(feature = "env")]
                ok!(self.add_env(matcher));
                ok!(self.add_defaults(matcher));
                return Validator::new(self.cmd).validate(parse_state, matcher);
            } else {
                // Start error processing
                let _ = self.resolve_pending(matcher);
                return Err(self.match_arg_error(&arg_os, valid_arg_found, trailing_values));
            }
        }

        if let Some(ref pos_sc_name) = subcmd_name {
            let sc_name = self
                .cmd
                .find_subcommand(pos_sc_name)
                .expect(INTERNAL_ERROR_MSG)
                .get_name()
                .to_owned();
            ok!(self.parse_subcommand(&sc_name, matcher, raw_args, args_cursor, keep_state));
        }

        ok!(self.resolve_pending(matcher));
        #[cfg(feature = "env")]
        ok!(self.add_env(matcher));
        ok!(self.add_defaults(matcher));
        Validator::new(self.cmd).validate(parse_state, matcher)
    }

pub fn is_last_set(&self) -> bool

Reports whether Arg::last is set

Examples found in repository

src/output/usage.rs (line 279)

    pub(crate) fn get_args(&self, incls: &[Id], force_optional: bool) -> Vec<StyledStr> {
        debug!("Usage::get_args: incls={:?}", incls,);

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => false,
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!("Usage::get_args: unrolled_reqs={:?}", unrolled_reqs);

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let stylized = arg.stylized(Some(!force_optional));
                if let Some(index) = arg.get_index() {
                    let new_len = index + 1;
                    if required_positionals.len() < new_len {
                        required_positionals.resize(new_len, None);
                    }
                    required_positionals[index] = Some(stylized);
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        for pos in self.cmd.get_positionals() {
            if pos.is_hide_set() {
                continue;
            }
            if required_groups_members.contains(pos.get_id()) {
                continue;
            }

            let index = pos.get_index().unwrap();
            let new_len = index + 1;
            if required_positionals.len() < new_len {
                required_positionals.resize(new_len, None);
            }
            if required_positionals[index].is_some() {
                if pos.is_last_set() {
                    let styled = required_positionals[index].take().unwrap();
                    let mut new = StyledStr::new();
                    new.literal("-- ");
                    new.extend(styled.into_iter());
                    required_positionals[index] = Some(new);
                }
            } else {
                let mut styled;
                if pos.is_last_set() {
                    styled = StyledStr::new();
                    styled.literal("[-- ");
                    styled.extend(pos.stylized(Some(true)).into_iter());
                    styled.literal("]");
                } else {
                    styled = pos.stylized(Some(false));
                }
                required_positionals[index] = Some(styled);
            }
            if pos.is_last_set() && force_optional {
                required_positionals[index] = None;
            }
        }

        let mut ret_val = Vec::new();
        if !force_optional {
            ret_val.extend(required_opts);
            ret_val.extend(required_groups);
        }
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_args: ret_val={:?}", ret_val);
        ret_val
    }

    pub(crate) fn get_required_usage_from(
        &self,
        incls: &[Id],
        matcher: Option<&ArgMatcher>,
        incl_last: bool,
    ) -> Vec<StyledStr> {
        debug!(
            "Usage::get_required_usage_from: incls={:?}, matcher={:?}, incl_last={:?}",
            incls,
            matcher.is_some(),
            incl_last
        );

        let required_owned;
        let required = if let Some(required) = self.required {
            required
        } else {
            required_owned = self.cmd.required_graph();
            &required_owned
        };

        let mut unrolled_reqs = Vec::new();
        for a in required.iter() {
            let is_relevant = |(val, req_arg): &(ArgPredicate, Id)| -> Option<Id> {
                let required = match val {
                    ArgPredicate::Equals(_) => {
                        if let Some(matcher) = matcher {
                            matcher.check_explicit(a, val)
                        } else {
                            false
                        }
                    }
                    ArgPredicate::IsPresent => true,
                };
                required.then(|| req_arg.clone())
            };

            for aa in self.cmd.unroll_arg_requires(is_relevant, a) {
                // if we don't check for duplicates here this causes duplicate error messages
                // see https://github.com/clap-rs/clap/issues/2770
                unrolled_reqs.push(aa);
            }
            // always include the required arg itself. it will not be enumerated
            // by unroll_requirements_for_arg.
            unrolled_reqs.push(a.clone());
        }
        debug!(
            "Usage::get_required_usage_from: unrolled_reqs={:?}",
            unrolled_reqs
        );

        let mut required_groups_members = FlatSet::new();
        let mut required_groups = FlatSet::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if self.cmd.find_group(req).is_some() {
                let group_members = self.cmd.unroll_args_in_group(req);
                let is_present = matcher
                    .map(|m| {
                        group_members
                            .iter()
                            .any(|arg| m.check_explicit(arg, &ArgPredicate::IsPresent))
                    })
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} group is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let elem = self.cmd.format_group(req);
                required_groups.insert(elem);
                required_groups_members.extend(group_members);
            } else {
                debug_assert!(self.cmd.find(req).is_some());
            }
        }

        let mut required_opts = FlatSet::new();
        let mut required_positionals = Vec::new();
        for req in unrolled_reqs.iter().chain(incls.iter()) {
            if let Some(arg) = self.cmd.find(req) {
                if required_groups_members.contains(arg.get_id()) {
                    continue;
                }

                let is_present = matcher
                    .map(|m| m.check_explicit(req, &ArgPredicate::IsPresent))
                    .unwrap_or(false);
                debug!(
                    "Usage::get_required_usage_from:iter:{:?} arg is_present={}",
                    req, is_present
                );
                if is_present {
                    continue;
                }

                let stylized = arg.stylized(Some(true));
                if let Some(index) = arg.get_index() {
                    if !arg.is_last_set() || incl_last {
                        let new_len = index + 1;
                        if required_positionals.len() < new_len {
                            required_positionals.resize(new_len, None);
                        }
                        required_positionals[index] = Some(stylized);
                    }
                } else {
                    required_opts.insert(stylized);
                }
            } else {
                debug_assert!(self.cmd.find_group(req).is_some());
            }
        }

        let mut ret_val = Vec::new();
        ret_val.extend(required_opts);
        ret_val.extend(required_groups);
        for pos in required_positionals.into_iter().flatten() {
            ret_val.push(pos);
        }

        debug!("Usage::get_required_usage_from: ret_val={:?}", ret_val);
        ret_val
    }

src/parser/validator.rs (line 285)

    fn validate_required(
        &mut self,
        matcher: &ArgMatcher,
        conflicts: &mut Conflicts,
    ) -> ClapResult<()> {
        debug!("Validator::validate_required: required={:?}", self.required);
        self.gather_requires(matcher);

        let mut missing_required = Vec::new();
        let mut highest_index = 0;

        let is_exclusive_present = matcher
            .arg_ids()
            .filter(|arg_id| matcher.check_explicit(arg_id, &ArgPredicate::IsPresent))
            .any(|id| {
                self.cmd
                    .find(id)
                    .map(|arg| arg.is_exclusive_set())
                    .unwrap_or_default()
            });
        debug!(
            "Validator::validate_required: is_exclusive_present={}",
            is_exclusive_present
        );

        for arg_or_group in self
            .required
            .iter()
            .filter(|r| !matcher.check_explicit(r, &ArgPredicate::IsPresent))
        {
            debug!("Validator::validate_required:iter:aog={:?}", arg_or_group);
            if let Some(arg) = self.cmd.find(arg_or_group) {
                debug!("Validator::validate_required:iter: This is an arg");
                if !is_exclusive_present && !self.is_missing_required_ok(arg, matcher, conflicts) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        arg.get_id()
                    );
                    missing_required.push(arg.get_id().clone());
                    if !arg.is_last_set() {
                        highest_index = highest_index.max(arg.get_index().unwrap_or(0));
                    }
                }
            } else if let Some(group) = self.cmd.find_group(arg_or_group) {
                debug!("Validator::validate_required:iter: This is a group");
                if !self
                    .cmd
                    .unroll_args_in_group(&group.id)
                    .iter()
                    .any(|a| matcher.check_explicit(a, &ArgPredicate::IsPresent))
                {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        group.get_id()
                    );
                    missing_required.push(group.get_id().clone());
                }
            }
        }

        // Validate the conditionally required args
        for a in self
            .cmd
            .get_arguments()
            .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
        {
            let mut required = false;

            for (other, val) in &a.r_ifs {
                if matcher.check_explicit(other, &ArgPredicate::Equals(val.into())) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        a.get_id()
                    );
                    required = true;
                }
            }

            let match_all = a.r_ifs_all.iter().all(|(other, val)| {
                matcher.check_explicit(other, &ArgPredicate::Equals(val.into()))
            });
            if match_all && !a.r_ifs_all.is_empty() {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if (!a.r_unless.is_empty() || !a.r_unless_all.is_empty())
                && self.fails_arg_required_unless(a, matcher)
            {
                debug!(
                    "Validator::validate_required:iter: Missing {:?}",
                    a.get_id()
                );
                required = true;
            }

            if required {
                missing_required.push(a.get_id().clone());
                if !a.is_last_set() {
                    highest_index = highest_index.max(a.get_index().unwrap_or(0));
                }
            }
        }

        // For display purposes, include all of the preceding positional arguments
        if !self.cmd.is_allow_missing_positional_set() {
            for pos in self
                .cmd
                .get_positionals()
                .filter(|a| !matcher.check_explicit(a.get_id(), &ArgPredicate::IsPresent))
            {
                if pos.get_index() < Some(highest_index) {
                    debug!(
                        "Validator::validate_required:iter: Missing {:?}",
                        pos.get_id()
                    );
                    missing_required.push(pos.get_id().clone());
                }
            }
        }

        if !missing_required.is_empty() {
            ok!(self.missing_required_error(matcher, missing_required));
        }

        Ok(())
    }

src/builder/debug_asserts.rs (line 243)

pub(crate) fn assert_app(cmd: &Command) {
    debug!("Command::_debug_asserts");

    let mut short_flags = vec![];
    let mut long_flags = vec![];

    // Invalid version flag settings
    if cmd.get_version().is_none() && cmd.get_long_version().is_none() {
        // PropagateVersion is meaningless if there is no version
        assert!(
            !cmd.is_propagate_version_set(),
            "Command {}: No version information via Command::version or Command::long_version to propagate",
            cmd.get_name(),
        );

        // Used `Command::mut_arg("version", ..) but did not provide any version information to display
        let version_needed = cmd
            .get_arguments()
            .filter(|x| matches!(x.get_action(), ArgAction::Version))
            .map(|x| x.get_id())
            .collect::<Vec<_>>();

        assert_eq!(version_needed, Vec::<&str>::new(), "Command {}: `ArgAction::Version` used without providing Command::version or Command::long_version"
            ,cmd.get_name()
        );
    }

    for sc in cmd.get_subcommands() {
        if let Some(s) = sc.get_short_flag().as_ref() {
            short_flags.push(Flag::Command(format!("-{}", s), sc.get_name()));
        }

        for short_alias in sc.get_all_short_flag_aliases() {
            short_flags.push(Flag::Command(format!("-{}", short_alias), sc.get_name()));
        }

        if let Some(l) = sc.get_long_flag().as_ref() {
            assert!(!l.starts_with('-'), "Command {}: long_flag {:?} must not start with a `-`, that will be handled by the parser", sc.get_name(), l);
            long_flags.push(Flag::Command(format!("--{}", l), sc.get_name()));
        }

        for long_alias in sc.get_all_long_flag_aliases() {
            long_flags.push(Flag::Command(format!("--{}", long_alias), sc.get_name()));
        }
    }

    for arg in cmd.get_arguments() {
        assert_arg(arg);

        assert!(
            !cmd.is_multicall_set(),
            "Command {}: Arguments like {} cannot be set on a multicall command",
            cmd.get_name(),
            arg.get_id()
        );

        if let Some(s) = arg.get_short() {
            short_flags.push(Flag::Arg(format!("-{}", s), arg.get_id().as_str()));
        }

        for (short_alias, _) in &arg.short_aliases {
            short_flags.push(Flag::Arg(
                format!("-{}", short_alias),
                arg.get_id().as_str(),
            ));
        }

        if let Some(l) = arg.get_long() {
            assert!(!l.starts_with('-'), "Argument {}: long {:?} must not start with a `-`, that will be handled by the parser", arg.get_id(), l);
            long_flags.push(Flag::Arg(format!("--{}", l), arg.get_id().as_str()));
        }

        for (long_alias, _) in &arg.aliases {
            long_flags.push(Flag::Arg(
                format!("--{}", long_alias),
                arg.get_id().as_str(),
            ));
        }

        // Name conflicts
        if let Some((first, second)) = cmd.two_args_of(|x| x.get_id() == arg.get_id()) {
            panic!(
            "Command {}: Argument names must be unique, but '{}' is in use by more than one argument or group{}",
            cmd.get_name(),
            arg.get_id(),
            duplicate_tip(cmd, first, second),
        );
        }

        // Long conflicts
        if let Some(l) = arg.get_long() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_long() == Some(l)) {
                panic!(
                    "Command {}: Long option names must be unique for each argument, \
                            but '--{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    l,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second)
                )
            }
        }

        // Short conflicts
        if let Some(s) = arg.get_short() {
            if let Some((first, second)) = cmd.two_args_of(|x| x.get_short() == Some(s)) {
                panic!(
                    "Command {}: Short option names must be unique for each argument, \
                            but '-{}' is in use by both '{}' and '{}'{}",
                    cmd.get_name(),
                    s,
                    first.get_id(),
                    second.get_id(),
                    duplicate_tip(cmd, first, second),
                )
            }
        }

        // Index conflicts
        if let Some(idx) = arg.index {
            if let Some((first, second)) =
                cmd.two_args_of(|x| x.is_positional() && x.get_index() == Some(idx))
            {
                panic!(
                    "Command {}: Argument '{}' has the same index as '{}' \
                    and they are both positional arguments\n\n\t \
                    Use `Arg::num_args(1..)` to allow one \
                    positional argument to take multiple values",
                    cmd.get_name(),
                    first.get_id(),
                    second.get_id()
                )
            }
        }

        // requires, r_if, r_unless
        for req in &arg.requires {
            assert!(
                cmd.id_exists(&req.1),
                "Command {}: Argument or group '{}' specified in 'requires*' for '{}' does not exist",
                cmd.get_name(),
                req.1,
                arg.get_id(),
            );
        }

        for req in &arg.r_ifs {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq*' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_ifs_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_if_eq_all`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(&req.0),
                "Command {}: Argument or group '{}' specified in 'required_if_eq_all' for '{}' does not exist",
                    cmd.get_name(),
                req.0,
                arg.get_id()
            );
        }

        for req in &arg.r_unless {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        for req in &arg.r_unless_all {
            assert!(
                !arg.is_required_set(),
                "Argument {}: `required` conflicts with `required_unless*`",
                arg.get_id()
            );
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'required_unless*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // blacklist
        for req in &arg.blacklist {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'conflicts_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        // overrides
        for req in &arg.overrides {
            assert!(
                cmd.id_exists(req),
                "Command {}: Argument or group '{}' specified in 'overrides_with*' for '{}' does not exist",
                    cmd.get_name(),
                req,
                arg.get_id(),
            );
        }

        if arg.is_last_set() {
            assert!(
                arg.get_long().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a long and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
            assert!(
                arg.get_short().is_none(),
                "Command {}: Flags or Options cannot have last(true) set. '{}' has both a short and last(true) set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }

        assert!(
            !(arg.is_required_set() && arg.is_global_set()),
            "Command {}: Global arguments cannot be required.\n\n\t'{}' is marked as both global and required",
                    cmd.get_name(),
            arg.get_id()
        );

        if arg.get_value_hint() == ValueHint::CommandWithArguments {
            assert!(
                arg.is_positional(),
                "Command {}: Argument '{}' has hint CommandWithArguments and must be positional.",
                cmd.get_name(),
                arg.get_id()
            );

            assert!(
                arg.is_trailing_var_arg_set() || arg.is_last_set(),
                "Command {}: Positional argument '{}' has hint CommandWithArguments, so Command must have `trailing_var_arg(true)` or `last(true)` set.",
                    cmd.get_name(),
                arg.get_id()
            );
        }
    }

    for group in cmd.get_groups() {
        let derive_hint = if cfg!(feature = "derive") {
            " (note: `Args` implicitly creates `ArgGroup`s; disable with `#[group(skip)]`"
        } else {
            ""
        };

        // Name conflicts
        assert!(
            cmd.get_groups().filter(|x| x.id == group.id).count() < 2,
            "Command {}: Argument group name must be unique\n\n\t'{}' is already in use{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        // Groups should not have naming conflicts with Args
        assert!(
            !cmd.get_arguments().any(|x| x.get_id() == group.get_id()),
            "Command {}: Argument group name '{}' must not conflict with argument name{}",
            cmd.get_name(),
            group.get_id(),
            derive_hint
        );

        for arg in &group.args {
            // Args listed inside groups should exist
            assert!(
                cmd.get_arguments().any(|x| x.get_id() == arg),
                "Command {}: Argument group '{}' contains non-existent argument '{}'",
                cmd.get_name(),
                group.get_id(),
                arg
            );
        }
    }

    // Conflicts between flags and subcommands

    long_flags.sort_unstable();
    short_flags.sort_unstable();

    detect_duplicate_flags(&long_flags, "long");
    detect_duplicate_flags(&short_flags, "short");

    let mut subs = FlatSet::new();
    for sc in cmd.get_subcommands() {
        assert!(
            subs.insert(sc.get_name()),
            "Command {}: command name `{}` is duplicated",
            cmd.get_name(),
            sc.get_name()
        );
        for alias in sc.get_all_aliases() {
            assert!(
                subs.insert(alias),
                "Command {}: command `{}` alias `{}` is duplicated",
                cmd.get_name(),
                sc.get_name(),
                alias
            );
        }
    }

    _verify_positionals(cmd);

    #[cfg(feature = "help")]
    if let Some(help_template) = cmd.get_help_template() {
        assert!(
            !help_template.to_string().contains("{flags}"),
            "Command {}: {}",
                    cmd.get_name(),
            "`{flags}` template variable was removed in clap3, they are now included in `{options}`",
        );
        assert!(
            !help_template.to_string().contains("{unified}"),
            "Command {}: {}",
            cmd.get_name(),
            "`{unified}` template variable was removed in clap3, use `{options}` instead"
        );
    }

    cmd._panic_on_missing_help(cmd.is_help_expected_set());
    assert_app_flags(cmd);
}

fn duplicate_tip(cmd: &Command, first: &Arg, second: &Arg) -> &'static str {
    if !cmd.is_disable_help_flag_set()
        && (first.get_id() == Id::HELP || second.get_id() == Id::HELP)
    {
        " (call `cmd.disable_help_flag(true)` to remove the auto-generated `--help`)"
    } else if !cmd.is_disable_version_flag_set()
        && (first.get_id() == Id::VERSION || second.get_id() == Id::VERSION)
    {
        " (call `cmd.disable_version_flag(true)` to remove the auto-generated `--version`)"
    } else {
        ""
    }
}

#[derive(Eq)]
enum Flag<'a> {
    Command(String, &'a str),
    Arg(String, &'a str),
}

impl PartialEq for Flag<'_> {
    fn eq(&self, other: &Flag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Flag<'_> {
    fn partial_cmp(&self, other: &Flag) -> Option<Ordering> {
        use Flag::*;

        match (self, other) {
            (Command(s1, _), Command(s2, _))
            | (Arg(s1, _), Arg(s2, _))
            | (Command(s1, _), Arg(s2, _))
            | (Arg(s1, _), Command(s2, _)) => {
                if s1 == s2 {
                    Some(Ordering::Equal)
                } else {
                    s1.partial_cmp(s2)
                }
            }
        }
    }
}

impl Ord for Flag<'_> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.partial_cmp(other).unwrap()
    }
}

fn detect_duplicate_flags(flags: &[Flag], short_or_long: &str) {
    use Flag::*;

    for (one, two) in find_duplicates(flags) {
        match (one, two) {
            (Command(flag, one), Command(_, another)) if one != another => panic!(
                "the '{}' {} flag is specified for both '{}' and '{}' subcommands",
                flag, short_or_long, one, another
            ),

            (Arg(flag, one), Arg(_, another)) if one != another => panic!(
                "{} option names must be unique, but '{}' is in use by both '{}' and '{}'",
                short_or_long, flag, one, another
            ),

            (Arg(flag, arg), Command(_, sub)) | (Command(flag, sub), Arg(_, arg)) => panic!(
                "the '{}' {} flag for the '{}' argument conflicts with the short flag \
                     for '{}' subcommand",
                flag, short_or_long, arg, sub
            ),

            _ => {}
        }
    }
}

/// Find duplicates in a sorted array.
///
/// The algorithm is simple: the array is sorted, duplicates
/// must be placed next to each other, we can check only adjacent elements.
fn find_duplicates<T: PartialEq>(slice: &[T]) -> impl Iterator<Item = (&T, &T)> {
    slice.windows(2).filter_map(|w| {
        if w[0] == w[1] {
            Some((&w[0], &w[1]))
        } else {
            None
        }
    })
}

fn assert_app_flags(cmd: &Command) {
    macro_rules! checker {
        ($a:ident requires $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if !cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} is required when AppSettings::{} is set.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}", s)
                }
            }
        };
        ($a:ident conflicts $($b:ident)|+) => {
            if cmd.$a() {
                let mut s = String::new();

                $(
                    if cmd.$b() {
                        use std::fmt::Write;
                        write!(&mut s, "  AppSettings::{} conflicts with AppSettings::{}.\n", std::stringify!($b), std::stringify!($a)).unwrap();
                    }
                )+

                if !s.is_empty() {
                    panic!("{}\n{}", cmd.get_name(), s)
                }
            }
        };
    }

    checker!(is_multicall_set conflicts is_no_binary_name_set);
}

#[cfg(debug_assertions)]
fn _verify_positionals(cmd: &Command) -> bool {
    debug!("Command::_verify_positionals");
    // Because you must wait until all arguments have been supplied, this is the first chance
    // to make assertions on positional argument indexes
    //
    // First we verify that the index highest supplied index, is equal to the number of
    // positional arguments to verify there are no gaps (i.e. supplying an index of 1 and 3
    // but no 2)

    let highest_idx = cmd
        .get_keymap()
        .keys()
        .filter_map(|x| {
            if let KeyType::Position(n) = x {
                Some(*n)
            } else {
                None
            }
        })
        .max()
        .unwrap_or(0);

    let num_p = cmd.get_keymap().keys().filter(|x| x.is_position()).count();

    assert!(
        highest_idx == num_p,
        "Found positional argument whose index is {} but there \
             are only {} positional arguments defined",
        highest_idx,
        num_p
    );

    for arg in cmd.get_arguments() {
        if arg.index.unwrap_or(0) == highest_idx {
            assert!(
                !arg.is_trailing_var_arg_set() || !arg.is_last_set(),
                "{}:{}: `Arg::trailing_var_arg` and `Arg::last` cannot be used together",
                cmd.get_name(),
                arg.get_id()
            );

            if arg.is_trailing_var_arg_set() {
                assert!(
                    arg.is_multiple(),
                    "{}:{}: `Arg::trailing_var_arg` must accept multiple values",
                    cmd.get_name(),
                    arg.get_id()
                );
            }
        } else {
            assert!(
                !arg.is_trailing_var_arg_set(),
                "{}:{}: `Arg::trailing_var_arg` can only apply to last positional",
                cmd.get_name(),
                arg.get_id()
            );
        }
    }

    // Next we verify that only the highest index has takes multiple arguments (if any)
    let only_highest = |a: &Arg| a.is_multiple() && (a.get_index().unwrap_or(0) != highest_idx);
    if cmd.get_positionals().any(only_highest) {
        // First we make sure if there is a positional that allows multiple values
        // the one before it (second to last) has one of these:
        //  * a value terminator
        //  * ArgSettings::Last
        //  * The last arg is Required

        // We can't pass the closure (it.next()) to the macro directly because each call to
        // find() (iterator, not macro) gets called repeatedly.
        let last = &cmd.get_keymap()[&KeyType::Position(highest_idx)];
        let second_to_last = &cmd.get_keymap()[&KeyType::Position(highest_idx - 1)];

        // Either the final positional is required
        // Or the second to last has a terminator or .last(true) set
        let ok = last.is_required_set()
            || (second_to_last.terminator.is_some() || second_to_last.is_last_set())
            || last.is_last_set();
        assert!(
            ok,
            "When using a positional argument with `.num_args(1..)` that is *not the \
                 last* positional argument, the last positional argument (i.e. the one \
                 with the highest index) *must* have .required(true) or .last(true) set."
        );

        // We make sure if the second to last is Multiple the last is ArgSettings::Last
        let ok = second_to_last.is_multiple() || last.is_last_set();
        assert!(
            ok,
            "Only the last positional argument, or second to last positional \
                 argument may be set to `.num_args(1..)`"
        );

        // Next we check how many have both Multiple and not a specific number of values set
        let count = cmd
            .get_positionals()
            .filter(|p| {
                p.is_multiple_values_set()
                    && !p.get_num_args().expect(INTERNAL_ERROR_MSG).is_fixed()
            })
            .count();
        let ok = count <= 1
            || (last.is_last_set()
                && last.is_multiple()
                && second_to_last.is_multiple()
                && count == 2);
        assert!(
            ok,
            "Only one positional argument with `.num_args(1..)` set is allowed per \
                 command, unless the second one also has .last(true) set"
        );
    }

    let mut found = false;

    if cmd.is_allow_missing_positional_set() {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required.
        let mut foundx2 = false;

        for p in cmd.get_positionals() {
            if foundx2 && !p.is_required_set() {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument by two or more: {:?} \
                         index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                if found {
                    foundx2 = true;
                    continue;
                }
                found = true;
                continue;
            } else {
                found = false;
            }
        }
    } else {
        // Check that if a required positional argument is found, all positions with a lower
        // index are also required
        for p in (1..=num_p).rev().filter_map(|n| cmd.get_keymap().get(&n)) {
            if found {
                assert!(
                    p.is_required_set(),
                    "Found non-required positional argument with a lower \
                         index than a required positional argument: {:?} index {:?}",
                    p.get_id(),
                    p.get_index()
                );
            } else if p.is_required_set() && !p.is_last_set() {
                // Args that .last(true) don't count since they can be required and have
                // positionals with a lower index that aren't required
                // Imagine: prog <req1> [opt1] -- <req2>
                // Both of these are valid invocations:
                //      $ prog r1 -- r2
                //      $ prog r1 o1 -- r2
                found = true;
                continue;
            }
        }
    }
    assert!(
        cmd.get_positionals().filter(|p| p.is_last_set()).count() < 2,
        "Only one positional argument may have last(true) set. Found two."
    );
    if cmd
        .get_positionals()
        .any(|p| p.is_last_set() && p.is_required_set())
        && cmd.has_subcommands()
        && !cmd.is_subcommand_negates_reqs_set()
    {
        panic!(
            "Having a required positional argument with .last(true) set *and* child \
                 subcommands without setting SubcommandsNegateReqs isn't compatible."
        );
    }

    true
}

src/parser/parser.rs (line 78)

    pub(crate) fn get_matches_with(
        &mut self,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        mut args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<()> {
        debug!("Parser::get_matches_with");
        // Verify all positional assertions pass

        let mut subcmd_name: Option<String> = None;
        let mut keep_state = false;
        let mut parse_state = ParseState::ValuesDone;
        let mut pos_counter = 1;

        // Already met any valid arg(then we shouldn't expect subcommands after it).
        let mut valid_arg_found = false;
        // If the user already passed '--'. Meaning only positional args follow.
        let mut trailing_values = false;

        // Count of positional args
        let positional_count = self
            .cmd
            .get_keymap()
            .keys()
            .filter(|x| x.is_position())
            .count();
        // If any arg sets .last(true)
        let contains_last = self.cmd.get_arguments().any(|x| x.is_last_set());

        while let Some(arg_os) = raw_args.next(&mut args_cursor) {
            // Recover the replaced items if any.
            if let Some(replaced_items) = arg_os
                .to_value()
                .ok()
                .and_then(|a| self.cmd.get_replacement(a))
            {
                debug!(
                    "Parser::get_matches_with: found replacer: {:?}, target: {:?}",
                    arg_os, replaced_items
                );
                raw_args.insert(&args_cursor, replaced_items);
                continue;
            }

            debug!(
                "Parser::get_matches_with: Begin parsing '{:?}' ({:?})",
                arg_os.to_value_os(),
                arg_os.to_value_os().as_raw_bytes()
            );

            // Has the user already passed '--'? Meaning only positional args follow
            if !trailing_values {
                if self.cmd.is_subcommand_precedence_over_arg_set()
                    || !matches!(parse_state, ParseState::Opt(_) | ParseState::Pos(_))
                {
                    // Does the arg match a subcommand name, or any of its aliases (if defined)
                    let sc_name = self.possible_subcommand(arg_os.to_value(), valid_arg_found);
                    debug!("Parser::get_matches_with: sc={:?}", sc_name);
                    if let Some(sc_name) = sc_name {
                        if sc_name == "help" && !self.cmd.is_disable_help_subcommand_set() {
                            ok!(self.parse_help_subcommand(raw_args.remaining(&mut args_cursor)));
                            unreachable!("`parse_help_subcommand` always errors");
                        } else {
                            subcmd_name = Some(sc_name.to_owned());
                        }
                        break;
                    }
                }

                if arg_os.is_escape() {
                    if matches!(&parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
                        self.cmd[opt].is_allow_hyphen_values_set())
                    {
                        // ParseResult::MaybeHyphenValue, do nothing
                    } else {
                        debug!("Parser::get_matches_with: setting TrailingVals=true");
                        trailing_values = true;
                        matcher.start_trailing();
                        continue;
                    }
                } else if let Some((long_arg, long_value)) = arg_os.to_long() {
                    let parse_result = ok!(self.parse_long_arg(
                        matcher,
                        long_arg,
                        long_value,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    debug!(
                        "Parser::get_matches_with: After parse_long_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            unreachable!("`to_long` always has the flag specified")
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            debug!(
                                "Parser::get_matches_with: FlagSubCommand found in long arg {:?}",
                                &name
                            );
                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            let remaining_args: Vec<_> =
                                raw_args.remaining(&mut args_cursor).collect();
                            return Err(self.did_you_mean_error(
                                &arg,
                                matcher,
                                &remaining_args,
                                trailing_values,
                            ));
                        }
                        ParseResult::UnneededAttachedValue { rest, used, arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::too_many_values(
                                self.cmd,
                                rest,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&used),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::AttachedValueNotConsumed => {
                            unreachable!()
                        }
                    }
                } else if let Some(short_arg) = arg_os.to_short() {
                    // Arg looks like a short flag, and not a possible number

                    // Try to parse short args like normal, if allow_hyphen_values or
                    // AllowNegativeNumbers is set, parse_short_arg will *not* throw
                    // an error, and instead return Ok(None)
                    let parse_result = ok!(self.parse_short_arg(
                        matcher,
                        short_arg,
                        &parse_state,
                        pos_counter,
                        &mut valid_arg_found,
                    ));
                    // If it's None, we then check if one of those two AppSettings was set
                    debug!(
                        "Parser::get_matches_with: After parse_short_arg {:?}",
                        parse_result
                    );
                    match parse_result {
                        ParseResult::NoArg => {
                            // Is a single dash `-`, try positional.
                        }
                        ParseResult::ValuesDone => {
                            parse_state = ParseState::ValuesDone;
                            continue;
                        }
                        ParseResult::Opt(id) => {
                            parse_state = ParseState::Opt(id);
                            continue;
                        }
                        ParseResult::FlagSubCommand(name) => {
                            // If there are more short flags to be processed, we should keep the state, and later
                            // revisit the current group of short flags skipping the subcommand.
                            keep_state = self
                                .flag_subcmd_at
                                .map(|at| {
                                    raw_args
                                        .seek(&mut args_cursor, clap_lex::SeekFrom::Current(-1));
                                    // Since we are now saving the current state, the number of flags to skip during state recovery should
                                    // be the current index (`cur_idx`) minus ONE UNIT TO THE LEFT of the starting position.
                                    self.flag_subcmd_skip = self.cur_idx.get() - at + 1;
                                })
                                .is_some();

                            debug!(
                                "Parser::get_matches_with:FlagSubCommandShort: subcmd_name={}, keep_state={}, flag_subcmd_skip={}",
                                name,
                                keep_state,
                                self.flag_subcmd_skip
                            );

                            subcmd_name = Some(name);
                            break;
                        }
                        ParseResult::EqualsNotProvided { arg } => {
                            let _ = self.resolve_pending(matcher);
                            return Err(ClapError::no_equals(
                                self.cmd,
                                arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::NoMatchingArg { arg } => {
                            let _ = self.resolve_pending(matcher);
                            // We already know it looks like a flag
                            let suggested_trailing_arg =
                                !trailing_values && self.cmd.has_positionals();
                            return Err(ClapError::unknown_argument(
                                self.cmd,
                                arg,
                                None,
                                suggested_trailing_arg,
                                Usage::new(self.cmd).create_usage_with_title(&[]),
                            ));
                        }
                        ParseResult::MaybeHyphenValue => {
                            // Maybe a hyphen value, do nothing.
                        }
                        ParseResult::UnneededAttachedValue { .. }
                        | ParseResult::AttachedValueNotConsumed => unreachable!(),
                    }
                }

                if let ParseState::Opt(id) = &parse_state {
                    // Assume this is a value of a previous arg.

                    // get the option so we can check the settings
                    let arg = &self.cmd[id];
                    let parse_result = if let Some(parse_result) =
                        self.check_terminator(arg, arg_os.to_value_os())
                    {
                        parse_result
                    } else {
                        let trailing_values = false;
                        let arg_values = matcher.pending_values_mut(id, None, trailing_values);
                        arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                        if matcher.needs_more_vals(arg) {
                            ParseResult::Opt(arg.get_id().clone())
                        } else {
                            ParseResult::ValuesDone
                        }
                    };
                    parse_state = match parse_result {
                        ParseResult::Opt(id) => ParseState::Opt(id),
                        ParseResult::ValuesDone => ParseState::ValuesDone,
                        _ => unreachable!(),
                    };
                    // get the next value from the iterator
                    continue;
                }
            }

            // Correct pos_counter.
            pos_counter = {
                let is_second_to_last = pos_counter + 1 == positional_count;

                // The last positional argument, or second to last positional
                // argument may be set to .multiple_values(true) or `.multiple_occurrences(true)`
                let low_index_mults = is_second_to_last
                    && self.cmd.get_positionals().any(|a| {
                        a.is_multiple() && (positional_count != a.get_index().unwrap_or(0))
                    })
                    && self
                        .cmd
                        .get_positionals()
                        .last()
                        .map_or(false, |p_name| !p_name.is_last_set());

                let missing_pos = self.cmd.is_allow_missing_positional_set()
                    && is_second_to_last
                    && !trailing_values;

                debug!(
                    "Parser::get_matches_with: Positional counter...{}",
                    pos_counter
                );
                debug!(
                    "Parser::get_matches_with: Low index multiples...{:?}",
                    low_index_mults
                );

                if low_index_mults || missing_pos {
                    let skip_current = if let Some(n) = raw_args.peek(&args_cursor) {
                        if let Some(arg) = self
                            .cmd
                            .get_positionals()
                            .find(|a| a.get_index() == Some(pos_counter))
                        {
                            // If next value looks like a new_arg or it's a
                            // subcommand, skip positional argument under current
                            // pos_counter(which means current value cannot be a
                            // positional argument with a value next to it), assume
                            // current value matches the next arg.
                            self.is_new_arg(&n, arg)
                                || self
                                    .possible_subcommand(n.to_value(), valid_arg_found)
                                    .is_some()
                        } else {
                            true
                        }
                    } else {
                        true
                    };

                    if skip_current {
                        debug!("Parser::get_matches_with: Bumping the positional counter...");
                        pos_counter + 1
                    } else {
                        pos_counter
                    }
                } else if trailing_values
                    && (self.cmd.is_allow_missing_positional_set() || contains_last)
                {
                    // Came to -- and one positional has .last(true) set, so we go immediately
                    // to the last (highest index) positional
                    debug!("Parser::get_matches_with: .last(true) and --, setting last pos");
                    positional_count
                } else {
                    pos_counter
                }
            };

            if let Some(arg) = self.cmd.get_keymap().get(&pos_counter) {
                if arg.is_last_set() && !trailing_values {
                    let _ = self.resolve_pending(matcher);
                    // Its already considered a positional, we don't need to suggest turning it
                    // into one
                    let suggested_trailing_arg = false;
                    return Err(ClapError::unknown_argument(
                        self.cmd,
                        arg_os.display().to_string(),
                        None,
                        suggested_trailing_arg,
                        Usage::new(self.cmd).create_usage_with_title(&[]),
                    ));
                }

                if arg.is_trailing_var_arg_set() {
                    trailing_values = true;
                }

                if matcher.pending_arg_id() != Some(arg.get_id()) || !arg.is_multiple_values_set() {
                    ok!(self.resolve_pending(matcher));
                }
                if let Some(_parse_result) = self.check_terminator(arg, arg_os.to_value_os()) {
                    debug!(
                        "Parser::get_matches_with: ignoring terminator result {:?}",
                        _parse_result
                    );
                } else {
                    let arg_values = matcher.pending_values_mut(
                        arg.get_id(),
                        Some(Identifier::Index),
                        trailing_values,
                    );
                    arg_values.push(arg_os.to_value_os().to_os_str().into_owned());
                }

                // Only increment the positional counter if it doesn't allow multiples
                if !arg.is_multiple() {
                    pos_counter += 1;
                    parse_state = ParseState::ValuesDone;
                } else {
                    parse_state = ParseState::Pos(arg.get_id().clone());
                }
                valid_arg_found = true;
            } else if let Some(external_parser) =
                self.cmd.get_external_subcommand_value_parser().cloned()
            {
                // Get external subcommand name
                let sc_name = match arg_os.to_value() {
                    Ok(s) => s.to_owned(),
                    Err(_) => {
                        let _ = self.resolve_pending(matcher);
                        return Err(ClapError::invalid_utf8(
                            self.cmd,
                            Usage::new(self.cmd).create_usage_with_title(&[]),
                        ));
                    }
                };

                // Collect the external subcommand args
                let mut sc_m = ArgMatcher::new(self.cmd);
                sc_m.start_occurrence_of_external(self.cmd);

                for raw_val in raw_args.remaining(&mut args_cursor) {
                    let val = ok!(external_parser.parse_ref(self.cmd, None, raw_val));
                    let external_id = Id::from_static_ref(Id::EXTERNAL);
                    sc_m.add_val_to(&external_id, val, raw_val.to_os_string());
                }

                matcher.subcommand(SubCommand {
                    name: sc_name,
                    matches: sc_m.into_inner(),
                });

                ok!(self.resolve_pending(matcher));
                #[cfg(feature = "env")]
                ok!(self.add_env(matcher));
                ok!(self.add_defaults(matcher));
                return Validator::new(self.cmd).validate(parse_state, matcher);
            } else {
                // Start error processing
                let _ = self.resolve_pending(matcher);
                return Err(self.match_arg_error(&arg_os, valid_arg_found, trailing_values));
            }
        }

        if let Some(ref pos_sc_name) = subcmd_name {
            let sc_name = self
                .cmd
                .find_subcommand(pos_sc_name)
                .expect(INTERNAL_ERROR_MSG)
                .get_name()
                .to_owned();
            ok!(self.parse_subcommand(&sc_name, matcher, raw_args, args_cursor, keep_state));
        }

        ok!(self.resolve_pending(matcher));
        #[cfg(feature = "env")]
        ok!(self.add_env(matcher));
        ok!(self.add_defaults(matcher));
        Validator::new(self.cmd).validate(parse_state, matcher)
    }

    fn match_arg_error(
        &self,
        arg_os: &clap_lex::ParsedArg<'_>,
        valid_arg_found: bool,
        trailing_values: bool,
    ) -> ClapError {
        // If argument follows a `--`
        if trailing_values {
            // If the arg matches a subcommand name, or any of its aliases (if defined)
            if self
                .possible_subcommand(arg_os.to_value(), valid_arg_found)
                .is_some()
            {
                return ClapError::unnecessary_double_dash(
                    self.cmd,
                    arg_os.display().to_string(),
                    Usage::new(self.cmd).create_usage_with_title(&[]),
                );
            }
        }

        let candidates = suggestions::did_you_mean(
            &arg_os.display().to_string(),
            self.cmd.all_subcommand_names(),
        );
        // If the argument looks like a subcommand.
        if !candidates.is_empty() {
            return ClapError::invalid_subcommand(
                self.cmd,
                arg_os.display().to_string(),
                candidates,
                self.cmd
                    .get_bin_name()
                    .unwrap_or_else(|| self.cmd.get_name())
                    .to_owned(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            );
        }

        // If the argument must be a subcommand.
        if self.cmd.has_subcommands()
            && (!self.cmd.has_positionals() || self.cmd.is_infer_subcommands_set())
        {
            return ClapError::unrecognized_subcommand(
                self.cmd,
                arg_os.display().to_string(),
                Usage::new(self.cmd).create_usage_with_title(&[]),
            );
        }

        let suggested_trailing_arg = !trailing_values
            && self.cmd.has_positionals()
            && (arg_os.is_long() || arg_os.is_short());
        ClapError::unknown_argument(
            self.cmd,
            arg_os.display().to_string(),
            None,
            suggested_trailing_arg,
            Usage::new(self.cmd).create_usage_with_title(&[]),
        )
    }

    // Checks if the arg matches a subcommand name, or any of its aliases (if defined)
    fn possible_subcommand(
        &self,
        arg: Result<&str, &RawOsStr>,
        valid_arg_found: bool,
    ) -> Option<&str> {
        debug!("Parser::possible_subcommand: arg={:?}", arg);
        let arg = some!(arg.ok());

        if !(self.cmd.is_args_conflicts_with_subcommands_set() && valid_arg_found) {
            if self.cmd.is_infer_subcommands_set() {
                // For subcommand `test`, we accepts it's prefix: `t`, `te`,
                // `tes` and `test`.
                let v = self
                    .cmd
                    .all_subcommand_names()
                    .filter(|s| s.starts_with(arg))
                    .collect::<Vec<_>>();

                if v.len() == 1 {
                    return Some(v[0]);
                }

                // If there is any ambiguity, fallback to non-infer subcommand
                // search.
            }
            if let Some(sc) = self.cmd.find_subcommand(arg) {
                return Some(sc.get_name());
            }
        }
        None
    }

    // Checks if the arg matches a long flag subcommand name, or any of its aliases (if defined)
    fn possible_long_flag_subcommand(&self, arg: &str) -> Option<&str> {
        debug!("Parser::possible_long_flag_subcommand: arg={:?}", arg);
        if self.cmd.is_infer_subcommands_set() {
            let options = self
                .cmd
                .get_subcommands()
                .fold(Vec::new(), |mut options, sc| {
                    if let Some(long) = sc.get_long_flag() {
                        if long.starts_with(arg) {
                            options.push(long);
                        }
                        options.extend(sc.get_all_aliases().filter(|alias| alias.starts_with(arg)))
                    }
                    options
                });
            if options.len() == 1 {
                return Some(options[0]);
            }

            for sc in options {
                if sc == arg {
                    return Some(sc);
                }
            }
        } else if let Some(sc_name) = self.cmd.find_long_subcmd(arg) {
            return Some(sc_name);
        }
        None
    }

    fn parse_help_subcommand(
        &self,
        cmds: impl Iterator<Item = &'cmd OsStr>,
    ) -> ClapResult<std::convert::Infallible> {
        debug!("Parser::parse_help_subcommand");

        let mut cmd = self.cmd.clone();
        let sc = {
            let mut sc = &mut cmd;

            for cmd in cmds {
                sc = if let Some(sc_name) =
                    sc.find_subcommand(cmd).map(|sc| sc.get_name().to_owned())
                {
                    sc._build_subcommand(&sc_name).unwrap()
                } else {
                    return Err(ClapError::unrecognized_subcommand(
                        sc,
                        cmd.to_string_lossy().into_owned(),
                        Usage::new(sc).create_usage_with_title(&[]),
                    ));
                };
            }

            sc
        };
        let parser = Parser::new(sc);

        Err(parser.help_err(true))
    }

    fn is_new_arg(&self, next: &clap_lex::ParsedArg<'_>, current_positional: &Arg) -> bool {
        #![allow(clippy::needless_bool)] // Prefer consistent if/else-if ladder

        debug!(
            "Parser::is_new_arg: {:?}:{}",
            next.to_value_os(),
            current_positional.get_id()
        );

        if self.cmd[current_positional.get_id()].is_allow_hyphen_values_set()
            || (self.cmd[current_positional.get_id()].is_allow_negative_numbers_set()
                && next.is_number())
        {
            // If allow hyphen, this isn't a new arg.
            debug!("Parser::is_new_arg: Allow hyphen");
            false
        } else if next.is_long() {
            // If this is a long flag, this is a new arg.
            debug!("Parser::is_new_arg: --<something> found");
            true
        } else if next.is_short() {
            // If this is a short flag, this is a new arg. But a singe '-' by
            // itself is a value and typically means "stdin" on unix systems.
            debug!("Parser::is_new_arg: -<something> found");
            true
        } else {
            // Nothing special, this is a value.
            debug!("Parser::is_new_arg: value");
            false
        }
    }

    fn parse_subcommand(
        &mut self,
        sc_name: &str,
        matcher: &mut ArgMatcher,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
        keep_state: bool,
    ) -> ClapResult<()> {
        debug!("Parser::parse_subcommand");

        let partial_parsing_enabled = self.cmd.is_ignore_errors_set();

        if let Some(sc) = self.cmd._build_subcommand(sc_name) {
            let mut sc_matcher = ArgMatcher::new(sc);

            debug!(
                "Parser::parse_subcommand: About to parse sc={}",
                sc.get_name()
            );

            {
                let mut p = Parser::new(sc);
                // HACK: maintain indexes between parsers
                // FlagSubCommand short arg needs to revisit the current short args, but skip the subcommand itself
                if keep_state {
                    p.cur_idx.set(self.cur_idx.get());
                    p.flag_subcmd_at = self.flag_subcmd_at;
                    p.flag_subcmd_skip = self.flag_subcmd_skip;
                }
                if let Err(error) = p.get_matches_with(&mut sc_matcher, raw_args, args_cursor) {
                    if partial_parsing_enabled {
                        debug!(
                            "Parser::parse_subcommand: ignored error in subcommand {}: {:?}",
                            sc_name, error
                        );
                    } else {
                        return Err(error);
                    }
                }
            }
            matcher.subcommand(SubCommand {
                name: sc.get_name().to_owned(),
                matches: sc_matcher.into_inner(),
            });
        }
        Ok(())
    }

    fn parse_long_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        long_arg: Result<&str, &RawOsStr>,
        long_value: Option<&RawOsStr>,
        parse_state: &ParseState,
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        // maybe here lifetime should be 'a
        debug!("Parser::parse_long_arg");

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt) if
            self.cmd[opt].is_allow_hyphen_values_set())
        {
            debug!("Parser::parse_long_arg: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        }

        debug!("Parser::parse_long_arg: Does it contain '='...");
        let long_arg = match long_arg {
            Ok(long_arg) => long_arg,
            Err(long_arg) => {
                return Ok(ParseResult::NoMatchingArg {
                    arg: long_arg.to_str_lossy().into_owned(),
                });
            }
        };
        if long_arg.is_empty() {
            debug_assert!(
                long_value.is_some(),
                "`--` should be filtered out before this point"
            );
        }

        let arg = if let Some(arg) = self.cmd.get_keymap().get(long_arg) {
            debug!("Parser::parse_long_arg: Found valid arg or flag '{}'", arg);
            Some((long_arg, arg))
        } else if self.cmd.is_infer_long_args_set() {
            self.cmd.get_arguments().find_map(|a| {
                if let Some(long) = a.get_long() {
                    if long.starts_with(long_arg) {
                        return Some((long, a));
                    }
                }
                a.aliases
                    .iter()
                    .find_map(|(alias, _)| alias.starts_with(long_arg).then(|| (alias.as_str(), a)))
            })
        } else {
            None
        };

        if let Some((_long_arg, arg)) = arg {
            let ident = Identifier::Long;
            *valid_arg_found = true;
            if arg.is_takes_value_set() {
                debug!(
                    "Parser::parse_long_arg({:?}): Found an arg with value '{:?}'",
                    long_arg, &long_value
                );
                let has_eq = long_value.is_some();
                self.parse_opt_value(ident, long_value, arg, matcher, has_eq)
            } else if let Some(rest) = long_value {
                let required = self.cmd.required_graph();
                debug!(
                    "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                    long_arg, rest
                );
                let mut used: Vec<Id> = matcher
                    .arg_ids()
                    .filter(|arg_id| {
                        matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
                    })
                    .filter(|&n| {
                        self.cmd.find(n).map_or(true, |a| {
                            !(a.is_hide_set() || required.contains(a.get_id()))
                        })
                    })
                    .cloned()
                    .collect();
                used.push(arg.get_id().clone());

                Ok(ParseResult::UnneededAttachedValue {
                    rest: rest.to_str_lossy().into_owned(),
                    used,
                    arg: arg.to_string(),
                })
            } else {
                debug!("Parser::parse_long_arg({:?}): Presence validated", long_arg);
                let trailing_idx = None;
                self.react(
                    Some(ident),
                    ValueSource::CommandLine,
                    arg,
                    vec![],
                    trailing_idx,
                    matcher,
                )
            }
        } else if let Some(sc_name) = self.possible_long_flag_subcommand(long_arg) {
            Ok(ParseResult::FlagSubCommand(sc_name.to_string()))
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
        {
            debug!(
                "Parser::parse_long_args: positional at {} allows hyphens",
                pos_counter
            );
            Ok(ParseResult::MaybeHyphenValue)
        } else {
            Ok(ParseResult::NoMatchingArg {
                arg: long_arg.to_owned(),
            })
        }
    }

    fn parse_short_arg(
        &mut self,
        matcher: &mut ArgMatcher,
        mut short_arg: clap_lex::ShortFlags<'_>,
        parse_state: &ParseState,
        // change this to possible pos_arg when removing the usage of &mut Parser.
        pos_counter: usize,
        valid_arg_found: &mut bool,
    ) -> ClapResult<ParseResult> {
        debug!("Parser::parse_short_arg: short_arg={:?}", short_arg);

        #[allow(clippy::blocks_in_if_conditions)]
        if matches!(parse_state, ParseState::Opt(opt) | ParseState::Pos(opt)
                if self.cmd[opt].is_allow_hyphen_values_set() || (self.cmd[opt].is_allow_negative_numbers_set() && short_arg.is_number()))
        {
            debug!("Parser::parse_short_args: prior arg accepts hyphenated values",);
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| arg.is_allow_negative_numbers_set())
            && short_arg.is_number()
        {
            debug!("Parser::parse_short_arg: negative number");
            return Ok(ParseResult::MaybeHyphenValue);
        } else if self
            .cmd
            .get_keymap()
            .get(&pos_counter)
            .map_or(false, |arg| {
                arg.is_allow_hyphen_values_set() && !arg.is_last_set()
            })
            && short_arg
                .clone()
                .any(|c| !c.map(|c| self.cmd.contains_short(c)).unwrap_or_default())
        {
            debug!(
                "Parser::parse_short_args: positional at {} allows hyphens",
                pos_counter
            );
            return Ok(ParseResult::MaybeHyphenValue);
        }

        let mut ret = ParseResult::NoArg;

        let skip = self.flag_subcmd_skip;
        self.flag_subcmd_skip = 0;
        let res = short_arg.advance_by(skip);
        debug_assert_eq!(
            res,
            Ok(()),
            "tracking of `flag_subcmd_skip` is off for `{:?}`",
            short_arg
        );
        while let Some(c) = short_arg.next_flag() {
            let c = match c {
                Ok(c) => c,
                Err(rest) => {
                    return Ok(ParseResult::NoMatchingArg {
                        arg: format!("-{}", rest.to_str_lossy()),
                    });
                }
            };
            debug!("Parser::parse_short_arg:iter:{}", c);

            // Check for matching short options, and return the name if there is no trailing
            // concatenated value: -oval
            // Option: -o
            // Value: val
            if let Some(arg) = self.cmd.get_keymap().get(&c) {
                let ident = Identifier::Short;
                debug!(
                    "Parser::parse_short_arg:iter:{}: Found valid opt or flag",
                    c
                );
                *valid_arg_found = true;
                if !arg.is_takes_value_set() {
                    let arg_values = Vec::new();
                    let trailing_idx = None;
                    ret = ok!(self.react(
                        Some(ident),
                        ValueSource::CommandLine,
                        arg,
                        arg_values,
                        trailing_idx,
                        matcher,
                    ));
                    continue;
                }

                // Check for trailing concatenated value
                //
                // Cloning the iterator, so we rollback if it isn't there.
                let val = short_arg.clone().next_value_os().unwrap_or_default();
                debug!(
                    "Parser::parse_short_arg:iter:{}: val={:?} (bytes), val={:?} (ascii), short_arg={:?}",
                    c, val, val.as_raw_bytes(), short_arg
                );
                let val = Some(val).filter(|v| !v.is_empty());

                // Default to "we're expecting a value later".
                //
                // If attached value is not consumed, we may have more short
                // flags to parse, continue.
                //
                // e.g. `-xvf`, when require_equals && x.min_vals == 0, we don't
                // consume the `vf`, even if it's provided as value.
                let (val, has_eq) = if let Some(val) = val.and_then(|v| v.strip_prefix('=')) {
                    (Some(val), true)
                } else {
                    (val, false)
                };
                match ok!(self.parse_opt_value(ident, val, arg, matcher, has_eq)) {
                    ParseResult::AttachedValueNotConsumed => continue,
                    x => return Ok(x),
                }
            }

            return if let Some(sc_name) = self.cmd.find_short_subcmd(c) {
                debug!("Parser::parse_short_arg:iter:{}: subcommand={}", c, sc_name);
                // Make sure indices get updated before reading `self.cur_idx`
                ok!(self.resolve_pending(matcher));
                self.cur_idx.set(self.cur_idx.get() + 1);
                debug!("Parser::parse_short_arg: cur_idx:={}", self.cur_idx.get());

                let name = sc_name.to_string();
                // Get the index of the previously saved flag subcommand in the group of flags (if exists).
                // If it is a new flag subcommand, then the formentioned index should be the current one
                // (ie. `cur_idx`), and should be registered.
                let cur_idx = self.cur_idx.get();
                self.flag_subcmd_at.get_or_insert(cur_idx);
                let done_short_args = short_arg.is_empty();
                if done_short_args {
                    self.flag_subcmd_at = None;
                }
                Ok(ParseResult::FlagSubCommand(name))
            } else {
                Ok(ParseResult::NoMatchingArg {
                    arg: format!("-{}", c),
                })
            };
        }
        Ok(ret)
    }

pub fn is_ignore_case_set(&self) -> bool

Reports whether Arg::ignore_case is set

Examples found in repository

src/parser/matches/matched_arg.rs (line 27)

    pub(crate) fn new_arg(arg: &crate::Arg) -> Self {
        let ignore_case = arg.is_ignore_case_set();
        Self {
            source: None,
            indices: Vec::new(),
            type_id: Some(arg.get_value_parser().type_id()),
            vals: Vec::new(),
            raw_vals: Vec::new(),
            ignore_case,
        }
    }

src/builder/value_parser.rs (line 1045)

    fn parse_ref(
        &self,
        cmd: &crate::Command,
        arg: Option<&crate::Arg>,
        value: &std::ffi::OsStr,
    ) -> Result<Self::Value, crate::Error> {
        let ignore_case = arg.map(|a| a.is_ignore_case_set()).unwrap_or(false);
        let possible_vals = || {
            E::value_variants()
                .iter()
                .filter_map(|v| v.to_possible_value())
                .filter(|v| !v.is_hide_set())
                .map(|v| v.get_name().to_owned())
                .collect::<Vec<_>>()
        };

        let value = ok!(value.to_str().ok_or_else(|| {
            crate::Error::invalid_value(
                cmd,
                value.to_string_lossy().into_owned(),
                &possible_vals(),
                arg.map(ToString::to_string)
                    .unwrap_or_else(|| "...".to_owned()),
            )
        }));
        let value = ok!(E::value_variants()
            .iter()
            .find(|v| {
                v.to_possible_value()
                    .expect("ValueEnum::value_variants contains only values with a corresponding ValueEnum::to_possible_value")
                    .matches(value, ignore_case)
            })
            .ok_or_else(|| {
            crate::Error::invalid_value(
                cmd,
                value.to_owned(),
                &possible_vals(),
                arg.map(ToString::to_string)
                    .unwrap_or_else(|| "...".to_owned()),
            )
            }))
            .clone();
        Ok(value)
    }

    fn possible_values(
        &self,
    ) -> Option<Box<dyn Iterator<Item = crate::builder::PossibleValue> + '_>> {
        Some(Box::new(
            E::value_variants()
                .iter()
                .filter_map(|v| v.to_possible_value()),
        ))
    }
}

impl<E: crate::ValueEnum + Clone + Send + Sync + 'static> Default for EnumValueParser<E> {
    fn default() -> Self {
        Self::new()
    }
}

/// Verify the value is from an enumerated set of [`PossibleValue`][crate::builder::PossibleValue].
///
/// See also:
/// - [`EnumValueParser`] for directly supporting [`ValueEnum`][crate::ValueEnum] types
/// - [`TypedValueParser::map`] for adapting values to a more specialized type, like an external
///   enums that can't implement [`ValueEnum`][crate::ValueEnum]
///
/// # Example
///
/// Usage:
/// ```rust
/// let mut cmd = clap::Command::new("raw")
///     .arg(
///         clap::Arg::new("color")
///             .value_parser(clap::builder::PossibleValuesParser::new(["always", "auto", "never"]))
///             .required(true)
///     );
///
/// let m = cmd.try_get_matches_from_mut(["cmd", "always"]).unwrap();
/// let port: &String = m.get_one("color")
///     .expect("required");
/// assert_eq!(port, "always");
/// ```
///
/// Semantics:
/// ```rust
/// # use std::ffi::OsStr;
/// # use clap::builder::TypedValueParser;
/// # let cmd = clap::Command::new("test");
/// # let arg = None;
/// let value_parser = clap::builder::PossibleValuesParser::new(["always", "auto", "never"]);
/// assert!(value_parser.parse_ref(&cmd, arg, OsStr::new("random")).is_err());
/// assert!(value_parser.parse_ref(&cmd, arg, OsStr::new("")).is_err());
/// assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("always")).unwrap(), "always");
/// assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("auto")).unwrap(), "auto");
/// assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("never")).unwrap(), "never");
/// ```
#[derive(Clone, Debug)]
pub struct PossibleValuesParser(Vec<super::PossibleValue>);

impl PossibleValuesParser {
    /// Verify the value is from an enumerated set pf [`PossibleValue`][crate::builder::PossibleValue].
    pub fn new(values: impl Into<PossibleValuesParser>) -> Self {
        values.into()
    }
}

impl TypedValueParser for PossibleValuesParser {
    type Value = String;

    fn parse_ref(
        &self,
        cmd: &crate::Command,
        arg: Option<&crate::Arg>,
        value: &std::ffi::OsStr,
    ) -> Result<Self::Value, crate::Error> {
        TypedValueParser::parse(self, cmd, arg, value.to_owned())
    }

    fn parse(
        &self,
        cmd: &crate::Command,
        arg: Option<&crate::Arg>,
        value: std::ffi::OsString,
    ) -> Result<String, crate::Error> {
        let value = ok!(value.into_string().map_err(|_| {
            crate::Error::invalid_utf8(
                cmd,
                crate::output::Usage::new(cmd).create_usage_with_title(&[]),
            )
        }));

        let ignore_case = arg.map(|a| a.is_ignore_case_set()).unwrap_or(false);
        if self.0.iter().any(|v| v.matches(&value, ignore_case)) {
            Ok(value)
        } else {
            let possible_vals = self
                .0
                .iter()
                .filter(|v| !v.is_hide_set())
                .map(|v| v.get_name().to_owned())
                .collect::<Vec<_>>();

            Err(crate::Error::invalid_value(
                cmd,
                value,
                &possible_vals,
                arg.map(ToString::to_string)
                    .unwrap_or_else(|| "...".to_owned()),
            ))
        }
    }

Trait Implementations

impl Clone for Arg

fn clone(&self) -> Arg

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Arg

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Arg

fn default() -> Arg

Returns the “default value” for a type.

impl Display for Arg

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<&Arg> for Arg

fn from(a: &Arg) -> Self

Converts to this type from the input type.

impl Ord for Arg

fn cmp(&self, other: &Arg) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl PartialEq<Arg> for Arg

fn eq(&self, other: &Arg) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<Arg> for Arg

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for Arg