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bynk_syntax/
error.rs

1//! Compiler diagnostics.
2//!
3//! Every error has a category (a dotted namespace string like
4//! `bynk.parse.expected_token`), a primary span, a primary message, and
5//! optionally some secondary labels and notes. Rendering goes through
6//! [`ariadne`] for source-pointing colour output.
7
8use ariadne::{Color, Config, IndexType, Label, Report, ReportKind};
9
10use crate::span::Span;
11
12/// A compile error.
13#[derive(Debug, Clone)]
14pub struct CompileError {
15    pub category: &'static str,
16    pub span: Span,
17    pub message: String,
18    pub labels: Vec<(Span, String)>,
19    pub notes: Vec<String>,
20    /// v0.26 (ADR 0054): machine-applicable fixes, authored at the diagnosis
21    /// site — the only place the exact spans and replacement are known.
22    /// Consumed by the LSP (`codeAction`) and, later, a CLI `--fix`.
23    pub suggestions: Vec<Suggestion>,
24}
25
26/// A structured fix for the error it is attached to (v0.26, ADR 0054).
27///
28/// `edits` are span → replacement: an empty replacement deletes the span; an
29/// empty span inserts at its position. Spans are offsets into the same source
30/// text as the error's own span.
31#[derive(Debug, Clone)]
32pub struct Suggestion {
33    /// Human-facing action title, e.g. "remove `Clock` from the `given` clause".
34    pub message: String,
35    pub edits: Vec<(Span, String)>,
36    pub applicability: Applicability,
37}
38
39/// Whether a [`Suggestion`] can be applied without review (mirrors rustc;
40/// gates a future CLI `--fix` and the LSP's one-click apply).
41#[derive(Debug, Clone, Copy, PartialEq, Eq)]
42pub enum Applicability {
43    /// The fix is exactly right — safe to apply mechanically.
44    MachineApplicable,
45    /// The fix contains placeholder text a human must complete; never
46    /// auto-applied.
47    HasPlaceholders,
48}
49
50/// Severity classification for a [`CompileError`]. Mirrors LSP severity levels
51/// so the LSP server can map diagnostics to the protocol without reinterpreting
52/// error categories. Lives in the syntax leaf beside `CompileError` (it
53/// classifies one): shared by the IDE diagnose path (`bynk-ide`) and the
54/// `short`/`json` renderers, without either depending on the other.
55#[derive(Debug, Clone, Copy, PartialEq, Eq)]
56pub enum Severity {
57    Error,
58    Warning,
59}
60
61impl Severity {
62    /// Classify a [`CompileError`] by its category prefix.
63    ///
64    /// `bynk.parse.orphan_doc_block`, `bynk.given.unused_capability`,
65    /// `bynk.list.deprecated_function`, and the `bynk.index.*` hygiene hints
66    /// (`missing`/`unused`, ADR 0118 D4) are warnings; everything else is an
67    /// error. Future categories can be added as the diagnostic surface grows.
68    pub fn for_error(err: &CompileError) -> Severity {
69        match err.category {
70            "bynk.parse.orphan_doc_block"
71            | "bynk.given.unused_capability"
72            | "bynk.list.deprecated_function"
73            | "bynk.index.missing"
74            | "bynk.index.unused"
75            // A computed secret name is legal and sometimes reasonable; the
76            // program is correct, `deploy` simply cannot see it (ADR 0196 D1).
77            | "bynk.secrets.computed_name" => Severity::Warning,
78            _ => Severity::Error,
79        }
80    }
81}
82
83/// Split diagnostics into `(errors, warnings)` by severity (ADR 0117). The build
84/// fails iff the `errors` half is non-empty; the `warnings` half surfaces but
85/// does not gate compilation. Relative order within each half is preserved.
86pub fn partition_by_severity(
87    diagnostics: Vec<CompileError>,
88) -> (Vec<CompileError>, Vec<CompileError>) {
89    diagnostics
90        .into_iter()
91        .partition(|d| Severity::for_error(d) == Severity::Error)
92}
93
94impl CompileError {
95    pub fn new(category: &'static str, span: Span, message: impl Into<String>) -> Self {
96        Self {
97            category,
98            span,
99            message: message.into(),
100            labels: Vec::new(),
101            notes: Vec::new(),
102            suggestions: Vec::new(),
103        }
104    }
105
106    pub fn with_label(mut self, span: Span, label: impl Into<String>) -> Self {
107        self.labels.push((span, label.into()));
108        self
109    }
110
111    pub fn with_note(mut self, note: impl Into<String>) -> Self {
112        self.notes.push(note.into());
113        self
114    }
115
116    /// Attach a machine-applicable fix (v0.26). Mirrors [`Self::with_note`];
117    /// the suggestion is authored where the diagnostic is raised.
118    pub fn with_suggestion(
119        mut self,
120        message: impl Into<String>,
121        edits: Vec<(Span, String)>,
122        applicability: Applicability,
123    ) -> Self {
124        self.suggestions.push(Suggestion {
125            message: message.into(),
126            edits,
127            applicability,
128        });
129        self
130    }
131
132    /// Build an [`ariadne::Report`] for this error, anchored to the given
133    /// filename. Colour is on (for the CLI and human-facing test output).
134    pub fn report<'a>(
135        &'a self,
136        filename: &'a str,
137    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
138        self.report_for(filename, usize::MAX)
139    }
140
141    /// [`Self::report`], bounded by the rendered source's byte length: a label
142    /// whose span lies past the end of the source belongs to *another* file
143    /// (e.g. a `uses`-imported callee's "declared here"), and rendering it
144    /// against this file would underline unrelated text. Such labels are
145    /// demoted to notes so the information survives without the misplacement.
146    pub fn report_for<'a>(
147        &'a self,
148        filename: &'a str,
149        source_len: usize,
150    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
151        self.report_with_config(filename, Config::default(), source_len)
152    }
153
154    /// Build a colourless [`ariadne::Report`], for transcripts committed to the
155    /// repo — no ANSI escape codes, so the output is byte-stable across machines.
156    pub fn report_plain<'a>(
157        &'a self,
158        filename: &'a str,
159    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
160        self.report_plain_for(filename, usize::MAX)
161    }
162
163    /// [`Self::report_plain`], bounded by the source length — see
164    /// [`Self::report_for`].
165    pub fn report_plain_for<'a>(
166        &'a self,
167        filename: &'a str,
168        source_len: usize,
169    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
170        self.report_with_config(filename, Config::default().with_color(false), source_len)
171    }
172
173    fn report_with_config<'a>(
174        &'a self,
175        filename: &'a str,
176        config: Config,
177        source_len: usize,
178    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
179        let primary_span = (filename, self.span.range());
180        // Spans are byte offsets into the UTF-8 source; ariadne 0.6 defaults
181        // to character indexing, which misplaces the underline on any line
182        // with non-ASCII text before the span.
183        let mut builder = Report::build(ReportKind::Error, primary_span.clone())
184            .with_config(config.with_index_type(IndexType::Byte))
185            .with_code(self.category)
186            .with_message(&self.message)
187            .with_label(
188                Label::new(primary_span)
189                    .with_message(&self.message)
190                    .with_color(Color::Red),
191            );
192
193        for (span, label) in &self.labels {
194            if span.end > source_len {
195                // The label's span lies in another file — demote to a note
196                // rather than underlining unrelated text in this one.
197                builder = builder.with_note(label);
198                continue;
199            }
200            builder = builder.with_label(
201                Label::new((filename, span.range()))
202                    .with_message(label)
203                    .with_color(Color::Yellow),
204            );
205        }
206
207        for note in &self.notes {
208            builder = builder.with_note(note);
209        }
210
211        builder.finish()
212    }
213}
214
215#[cfg(test)]
216mod warning_channel_tests {
217    use super::*;
218    use crate::span::Span;
219
220    #[test]
221    fn partition_splits_by_severity() {
222        let warn = CompileError::new("bynk.given.unused_capability", Span::default(), "unused");
223        let err = CompileError::new("bynk.types.argument_mismatch", Span::default(), "bad");
224        let (errors, warnings) = partition_by_severity(vec![warn, err]);
225        assert_eq!(errors.len(), 1);
226        assert_eq!(errors[0].category, "bynk.types.argument_mismatch");
227        assert_eq!(warnings.len(), 1);
228        assert_eq!(warnings[0].category, "bynk.given.unused_capability");
229    }
230}