Error

Struct Error 

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pub struct Error { /* private fields */ }
Expand description

The fundamental error type used by this library.

An error type which encapsulates information about whether an error is the result of something the user did, or a system failure outside their control. These errors include a description of what occurred, advice on how to proceed and references to the causal chain which led to this failure.

§Examples

use human_errors;

let err = human_errors::user(
  "We could not open the config file you provided.",
  &["Make sure that the file exists and is readable by the application."],
);

// Prints the error and any advice for the user.
println!("{}", err)

Implementations§

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impl Error

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pub fn new<E: Into<Box<dyn Error + Send + Sync>>>( error: E, kind: Kind, advice: &'static [&'static str], ) -> Self

Constructs a new Error.

§Examples
use human_errors;
let err = human_errors::Error::new(
    "Low-level IO error details",
    human_errors::Kind::System,
    &["Try restarting the application", "If the problem persists, contact support"]
);
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pub fn is(&self, kind: Kind) -> bool

Checks if this error is of a specific kind.

Returns true if this error matches the provided Kind, otherwise false.

§Examples
use human_errors;

let err = human_errors::user(
  "We could not open the config file you provided.",
  &["Make sure that the file exists and is readable by the application."],
);

// Prints "is_user?: true"
println!("is_user?: {}", err.is(human_errors::Kind::User));
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pub fn description(&self) -> String

Gets the description message from this error.

Gets the description which was provided as the first argument when constructing this error.

§Examples
use human_errors;

let err = human_errors::user(
  "We could not open the config file you provided.",
  &["Make sure that the file exists and is readable by the application."],
);

// Prints: "We could not open the config file you provided."
println!("{}", err.description())
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pub fn advice(&self) -> Vec<&'static str>

Gets the advice associated with this error and its causes.

Gathers all advice from this error and any causal errors it wraps, returning a deduplicated list of suggestions for how a user should deal with this error.

§Examples
use human_errors;

let err = human_errors::wrap_user(
  human_errors::user(
    "We could not find a file at /home/user/.config/demo.yml",
    &["Make sure that the file exists and is readable by the application."]
  ),
  "We could not open the config file you provided.",
  &["Make sure that you've specified a valid config file with the --config option."],
);

// Prints:
// - Make sure that the file exists and is readable by the application.
// - Make sure that you've specified a valid config file with the --config option.
for tip in err.advice() {
    println!("- {}", tip);
}
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pub fn message(&self) -> String

Gets the formatted error and its advice.

Generates a string containing the description of the error and any causes, as well as a list of suggestions for how a user should deal with this error. The “deepest” error’s advice is presented first, with successively higher errors appearing lower in the list. This is done because the most specific error is the one most likely to have the best advice on how to resolve the problem.

§Examples
use human_errors;

let err = human_errors::wrap_user(
  human_errors::user(
    "We could not find a file at /home/user/.config/demo.yml",
    &["Make sure that the file exists and is readable by the application."]
  ),
  "We could not open the config file you provided.",
  &["Make sure that you've specified a valid config file with the --config option."],
);

// Prints a message like the following:
// We could not open the config file you provided. (User error)
//
// This was caused by:
// We could not find a file at /home/user/.config/demo.yml
//
// To try and fix this, you can:
//  - Make sure that the file exists and is readable by the application.
//  - Make sure that you've specified a valid config file with the --config option.
println!("{}", err.message());

Trait Implementations§

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impl Debug for Error

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Display for Error

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Error for Error

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fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
1.0.0 · Source§

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
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fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
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impl From<Error> for Error

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fn from(err: Error) -> Self

Converts to this type from the input type.
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impl From<FromUtf8Error> for Error

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fn from(err: FromUtf8Error) -> Self

Converts to this type from the input type.

Auto Trait Implementations§

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impl Freeze for Error

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impl !RefUnwindSafe for Error

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impl Send for Error

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impl Sync for Error

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impl Unpin for Error

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impl !UnwindSafe for Error

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToString for T
where T: Display + ?Sized,

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fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.