sva_core/
cli_error.rs

1// Concern: enumerates the pipeline error variants, exit codes, JSON codes and diagnostics | Non-concern: JSON envelope framing (output.rs), argv (sva-cli) | IO: none
2
3use std::fmt;
4
5use sva_ast::Refusal;
6use sva_engine::EngineError;
7
8use crate::lint_code::LintCode;
9use crate::output::{Diagnostic, Severity};
10
11/// One `lint` finding: its code, how hard it lands, and the node it is against.
12#[derive(Debug)]
13pub struct LintViolation {
14    pub code: LintCode,
15    pub severity: Severity,
16    pub subject: String,
17    pub message: String,
18    pub line: Option<usize>,
19}
20
21/// Every expected failure mode this crate can hit; none of them a panic.
22#[derive(Debug)]
23pub enum CliError {
24    Usage(String),
25    Refusals(Vec<Refusal>),
26    Engine(EngineError),
27    BadTempo(String),
28    BadProbe(String),
29    Io(String),
30    /// A path the caller named that nothing answers for; an `Io` is one that is there.
31    NotFound(String),
32    /// A name already taken, as opposed to an `Io` the filesystem raised.
33    Conflict {
34        by: &'static str,
35        message: String,
36    },
37    /// Every `LintViolation` the scan found, not just the first.
38    LintRefused(Vec<LintViolation>),
39}
40
41impl From<EngineError> for CliError {
42    fn from(e: EngineError) -> CliError {
43        CliError::Engine(e)
44    }
45}
46
47fn engine_error_path(e: &EngineError) -> Option<String> {
48    match e {
49        EngineError::Binding { node, .. } => Some(node.clone()),
50        EngineError::UnknownNode(p)
51        | EngineError::AmbiguousNode(p, _)
52        | EngineError::RefAboveRoot(p, _) => Some(p.clone()),
53        other => other.at().map(|at| at.node.clone()),
54    }
55}
56
57fn engine_error_span(e: &EngineError) -> Option<(usize, usize)> {
58    let span = match e {
59        EngineError::Binding { span, .. } => *span,
60        other => other.at().and_then(|at| at.span),
61    }?;
62    Some((span.start, span.end - span.start))
63}
64
65fn names_no_node(e: &EngineError) -> bool {
66    matches!(e, EngineError::UnknownNode(_))
67}
68
69impl CliError {
70    pub fn exit_code(&self) -> u8 {
71        match self {
72            CliError::Engine(e) if names_no_node(e) => 24,
73            CliError::Usage(_)
74            | CliError::Refusals(_)
75            | CliError::Engine(_)
76            | CliError::BadTempo(_)
77            | CliError::BadProbe(_)
78            | CliError::LintRefused(_) => 3,
79            CliError::Conflict { .. } => 4,
80            CliError::NotFound(_) => 24,
81            CliError::Io(_) => 1,
82        }
83    }
84
85    pub fn code(&self) -> &'static str {
86        match self {
87            CliError::Engine(e) if names_no_node(e) => "not_found",
88            CliError::Usage(_)
89            | CliError::Refusals(_)
90            | CliError::Engine(_)
91            | CliError::BadTempo(_)
92            | CliError::BadProbe(_)
93            | CliError::LintRefused(_) => "validation_error",
94            CliError::Conflict { .. } => "conflict",
95            CliError::NotFound(_) => "not_found",
96            CliError::Io(_) => "internal_error",
97        }
98    }
99
100    pub fn message(&self) -> String {
101        match self {
102            CliError::Usage(m) => m.clone(),
103            CliError::Refusals(rs) => format!("{} refusal(s) parsing the composition", rs.len()),
104            CliError::Engine(e) => e.to_string(),
105            CliError::BadTempo(m) | CliError::BadProbe(m) | CliError::Io(m) => m.clone(),
106            CliError::NotFound(m) => m.clone(),
107            CliError::Conflict { message, .. } => message.clone(),
108            CliError::LintRefused(vs) => format!(
109                "{} lint violation(s)",
110                vs.iter().filter(|v| v.severity == Severity::Error).count()
111            ),
112        }
113    }
114
115    /// Per-finding detail; empty only where the failure has no subject to locate it against.
116    pub fn diagnostics(&self) -> Vec<Diagnostic> {
117        match self {
118            CliError::Refusals(rs) => rs
119                .iter()
120                .map(|r| {
121                    Diagnostic::new(r.code.code_str(), r.reason.clone()).at(
122                        Some(r.at.path.clone()),
123                        Some((r.at.span.start, r.at.span.end - r.at.span.start)),
124                    )
125                })
126                .collect(),
127            CliError::Engine(e) => vec![engine_diagnostic(e)],
128            CliError::BadTempo(m) => vec![
129                Diagnostic::new("tempo.invalid_bpm_meter", m.clone()).helped(
130                    "state `variables/bpm` as a positive number and `variables/meter` as \
131                     `<beats>/<note>`, e.g. `4/4`",
132                ),
133            ],
134            CliError::BadProbe(m) => vec![Diagnostic::new("probe.invalid_expression", m.clone())
135                .helped("name a node path that exists, or an expression in the same grammar a node file holds")],
136            CliError::Usage(m) => vec![Diagnostic::new("cli.invalid_argument", without_usage(m))
137                .helped("`sva-cli --help` states every subcommand, its arguments and their defaults")],
138            CliError::Conflict { by, message } => vec![
139                Diagnostic::new(format!("{by}.already_exists"), message.clone())
140                    .helped("pick a name nothing occupies, or remove what is there first"),
141            ],
142            CliError::NotFound(m) => vec![
143                Diagnostic::new("io.no_such_path", m.clone())
144                    .helped("name a path that exists; `sva-cli lint` says what a composition holds"),
145            ],
146            CliError::LintRefused(vs) => vs
147                .iter()
148                .map(|v| lint_diagnostic(v.code, &v.subject, &v.message, v.severity, v.line))
149                .collect(),
150            CliError::Io(_) => Vec::new(),
151        }
152    }
153}
154
155/// `Display` runs a refusal's three parts together; a diagnostic keeps each apart.
156fn engine_diagnostic(e: &EngineError) -> Diagnostic {
157    let held = match e {
158        EngineError::Refused(d) => {
159            Diagnostic::new(d.code.clone(), d.message.clone()).helped(d.help.clone())
160        }
161        other => Diagnostic::new(other.code(), other.to_string()),
162    };
163    held.at(engine_error_path(e), engine_error_span(e))
164}
165
166/// `error.message` already carries the banner; repeating it here doubles a response. Every
167/// `Usage` states its reason first, so a bare banner is a call site that forgot to.
168fn without_usage(message: &str) -> &str {
169    match message.split_once("\nusage:") {
170        Some((reason, _)) => reason,
171        None => {
172            debug_assert!(
173                !message.starts_with("usage:"),
174                "a usage refusal states its reason before the banner"
175            );
176            message
177        }
178    }
179}
180
181/// The one place a `lint` code becomes a diagnostic, so both of `lint`'s response paths
182/// namespace it, locate it and help against it identically.
183pub fn lint_diagnostic(
184    code: LintCode,
185    subject: &str,
186    message: &str,
187    severity: Severity,
188    line: Option<usize>,
189) -> Diagnostic {
190    Diagnostic::new(
191        format!("lint.{}", code.code_str()).replace('-', "_"),
192        message,
193    )
194    .with_severity(severity)
195    .at(Some(subject.to_string()), None)
196    .on_line(line)
197    .helped(code.help())
198}
199
200impl fmt::Display for CliError {
201    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
202        write!(f, "{}", self.message())
203    }
204}
205
206impl std::error::Error for CliError {}
207
208#[cfg(test)]
209mod tests {
210    use super::*;
211
212    /// The `cli` standard's table, and its rule that code and exit code always agree.
213    #[test]
214    fn every_variant_answers_the_standards_own_code_and_exit_code() {
215        let cases: [(CliError, &str, u8); 7] = [
216            (CliError::NotFound("gone".to_string()), "not_found", 24),
217            (
218                CliError::Engine(EngineError::UnknownNode("gone".to_string())),
219                "not_found",
220                24,
221            ),
222            (
223                CliError::Usage("bad flag".to_string()),
224                "validation_error",
225                3,
226            ),
227            (
228                CliError::BadTempo("bad bpm".to_string()),
229                "validation_error",
230                3,
231            ),
232            (
233                CliError::Conflict {
234                    by: "new",
235                    message: "taken".to_string(),
236                },
237                "conflict",
238                4,
239            ),
240            (CliError::Io("disk".to_string()), "internal_error", 1),
241            (CliError::LintRefused(Vec::new()), "validation_error", 3),
242        ];
243        for (err, code, exit) in cases {
244            assert_eq!(err.code(), code, "{err:?}");
245            assert_eq!(err.exit_code(), exit, "{err:?}");
246        }
247    }
248
249    /// A diagnostic's `message` is a one-line summary, so the banner stays out of it.
250    #[test]
251    fn an_argument_diagnostic_carries_the_reason_without_the_usage_banner() {
252        for message in [
253            "lint takes only [<node|expression>], not `--path`",
254            "no subcommand given",
255        ] {
256            let full = format!("{message}\nusage: sva-cli render [...]\nquery options: [...]");
257            let [d] = &CliError::Usage(full).diagnostics()[..] else {
258                panic!("a usage refusal carries exactly one diagnostic");
259            };
260            assert_eq!(d.code, "cli.invalid_argument");
261            assert_eq!(d.message, message);
262            assert!(d.help.is_some(), "and says where to look");
263        }
264    }
265}
sva_core/cli_error.rs

sva_core/
cli_error.rs
