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

sva_core/
cli_error.rs
