1 //! A JSON emitter for errors.
3 //! This works by converting errors to a simplified structural format (see the
4 //! structs at the start of the file) and then serializing them. These should
5 //! contain as much information about the error as possible.
7 //! The format of the JSON output should be considered *unstable*. For now the
8 //! structs at the end of this file (Diagnostic*) specify the error format.
10 // FIXME: spec the JSON output properly.
12 use rustc_span::source_map::{FilePathMapping, SourceMap};
14 use crate::emitter::{Emitter, HumanReadableErrorType};
15 use crate::registry::Registry;
16 use crate::translation::Translate;
17 use crate::DiagnosticId;
19 CodeSuggestion, FluentBundle, LazyFallbackBundle, MultiSpan, SpanLabel, SubDiagnostic,
21 use rustc_lint_defs::Applicability;
23 use rustc_data_structures::sync::Lrc;
24 use rustc_error_messages::FluentArgs;
25 use rustc_span::hygiene::ExpnData;
27 use std::io::{self, Write};
29 use std::sync::{Arc, Mutex};
37 pub struct JsonEmitter {
38 dst: Box<dyn Write + Send>,
39 registry: Option<Registry>,
41 fluent_bundle: Option<Lrc<FluentBundle>>,
42 fallback_bundle: LazyFallbackBundle,
45 json_rendered: HumanReadableErrorType,
46 diagnostic_width: Option<usize>,
47 macro_backtrace: bool,
52 registry: Option<Registry>,
53 source_map: Lrc<SourceMap>,
54 fluent_bundle: Option<Lrc<FluentBundle>>,
55 fallback_bundle: LazyFallbackBundle,
57 json_rendered: HumanReadableErrorType,
58 diagnostic_width: Option<usize>,
59 macro_backtrace: bool,
62 dst: Box::new(io::BufWriter::new(io::stderr())),
77 json_rendered: HumanReadableErrorType,
78 fluent_bundle: Option<Lrc<FluentBundle>>,
79 fallback_bundle: LazyFallbackBundle,
80 diagnostic_width: Option<usize>,
81 macro_backtrace: bool,
83 let file_path_mapping = FilePathMapping::empty();
86 Lrc::new(SourceMap::new(file_path_mapping)),
97 dst: Box<dyn Write + Send>,
98 registry: Option<Registry>,
99 source_map: Lrc<SourceMap>,
100 fluent_bundle: Option<Lrc<FluentBundle>>,
101 fallback_bundle: LazyFallbackBundle,
103 json_rendered: HumanReadableErrorType,
104 diagnostic_width: Option<usize>,
105 macro_backtrace: bool,
121 pub fn ui_testing(self, ui_testing: bool) -> Self {
122 Self { ui_testing, ..self }
126 impl Translate for JsonEmitter {
127 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
128 self.fluent_bundle.as_ref()
131 fn fallback_fluent_bundle(&self) -> &FluentBundle {
132 &**self.fallback_bundle
136 impl Emitter for JsonEmitter {
137 fn emit_diagnostic(&mut self, diag: &crate::Diagnostic) {
138 let data = Diagnostic::from_errors_diagnostic(diag, self);
139 let result = if self.pretty {
140 writeln!(&mut self.dst, "{}", serde_json::to_string_pretty(&data).unwrap())
142 writeln!(&mut self.dst, "{}", serde_json::to_string(&data).unwrap())
144 .and_then(|_| self.dst.flush());
145 if let Err(e) = result {
146 panic!("failed to print diagnostics: {:?}", e);
150 fn emit_artifact_notification(&mut self, path: &Path, artifact_type: &str) {
151 let data = ArtifactNotification { artifact: path, emit: artifact_type };
152 let result = if self.pretty {
153 writeln!(&mut self.dst, "{}", serde_json::to_string_pretty(&data).unwrap())
155 writeln!(&mut self.dst, "{}", serde_json::to_string(&data).unwrap())
157 .and_then(|_| self.dst.flush());
158 if let Err(e) = result {
159 panic!("failed to print notification: {:?}", e);
163 fn emit_future_breakage_report(&mut self, diags: Vec<crate::Diagnostic>) {
164 let data: Vec<FutureBreakageItem> = diags
167 if diag.level == crate::Level::Allow {
168 diag.level = crate::Level::Warning(None);
170 FutureBreakageItem { diagnostic: Diagnostic::from_errors_diagnostic(&diag, self) }
173 let report = FutureIncompatReport { future_incompat_report: data };
174 let result = if self.pretty {
175 writeln!(&mut self.dst, "{}", serde_json::to_string_pretty(&report).unwrap())
177 writeln!(&mut self.dst, "{}", serde_json::to_string(&report).unwrap())
179 .and_then(|_| self.dst.flush());
180 if let Err(e) = result {
181 panic!("failed to print future breakage report: {:?}", e);
185 fn emit_unused_externs(&mut self, lint_level: rustc_lint_defs::Level, unused_externs: &[&str]) {
186 let lint_level = lint_level.as_str();
187 let data = UnusedExterns { lint_level, unused_extern_names: unused_externs };
188 let result = if self.pretty {
189 writeln!(&mut self.dst, "{}", serde_json::to_string_pretty(&data).unwrap())
191 writeln!(&mut self.dst, "{}", serde_json::to_string(&data).unwrap())
193 .and_then(|_| self.dst.flush());
194 if let Err(e) = result {
195 panic!("failed to print unused externs: {:?}", e);
199 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
203 fn should_show_explain(&self) -> bool {
204 !matches!(self.json_rendered, HumanReadableErrorType::Short(_))
208 // The following data types are provided just for serialisation.
212 /// The primary error message.
214 code: Option<DiagnosticCode>,
215 /// "error: internal compiler error", "error", "warning", "note", "help".
217 spans: Vec<DiagnosticSpan>,
218 /// Associated diagnostic messages.
219 children: Vec<Diagnostic>,
220 /// The message as rustc would render it.
221 rendered: Option<String>,
225 struct DiagnosticSpan {
232 /// 1-based, character offset.
235 /// Is this a "primary" span -- meaning the point, or one of the points,
236 /// where the error occurred?
238 /// Source text from the start of line_start to the end of line_end.
239 text: Vec<DiagnosticSpanLine>,
240 /// Label that should be placed at this location (if any)
241 label: Option<String>,
242 /// If we are suggesting a replacement, this will contain text
243 /// that should be sliced in atop this span.
244 suggested_replacement: Option<String>,
245 /// If the suggestion is approximate
246 suggestion_applicability: Option<Applicability>,
247 /// Macro invocations that created the code at this span, if any.
248 expansion: Option<Box<DiagnosticSpanMacroExpansion>>,
252 struct DiagnosticSpanLine {
255 /// 1-based, character offset in self.text.
256 highlight_start: usize,
258 highlight_end: usize,
262 struct DiagnosticSpanMacroExpansion {
263 /// span where macro was applied to generate this code; note that
264 /// this may itself derive from a macro (if
265 /// `span.expansion.is_some()`)
266 span: DiagnosticSpan,
268 /// name of macro that was applied (e.g., "foo!" or "#[derive(Eq)]")
269 macro_decl_name: String,
271 /// span where macro was defined (if known)
272 def_site_span: DiagnosticSpan,
276 struct DiagnosticCode {
279 /// An explanation for the code.
280 explanation: Option<&'static str>,
284 struct ArtifactNotification<'a> {
285 /// The path of the artifact.
287 /// What kind of artifact we're emitting.
292 struct FutureBreakageItem {
293 diagnostic: Diagnostic,
297 struct FutureIncompatReport {
298 future_incompat_report: Vec<FutureBreakageItem>,
301 // NOTE: Keep this in sync with the equivalent structs in rustdoc's
302 // doctest component (as well as cargo).
303 // We could unify this struct the one in rustdoc but they have different
304 // ownership semantics, so doing so would create wasteful allocations.
306 struct UnusedExterns<'a, 'b, 'c> {
307 /// The severity level of the unused dependencies lint
309 /// List of unused externs by their names.
310 unused_extern_names: &'b [&'c str],
314 fn from_errors_diagnostic(diag: &crate::Diagnostic, je: &JsonEmitter) -> Diagnostic {
315 let args = je.to_fluent_args(diag.args());
316 let sugg = diag.suggestions.iter().flatten().map(|sugg| {
317 let translated_message = je.translate_message(&sugg.msg, &args);
319 message: translated_message.to_string(),
322 spans: DiagnosticSpan::from_suggestion(sugg, &args, je),
328 // generate regular command line output and store it in the json
330 // A threadsafe buffer for writing.
331 #[derive(Default, Clone)]
332 struct BufWriter(Arc<Mutex<Vec<u8>>>);
334 impl Write for BufWriter {
335 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
336 self.0.lock().unwrap().write(buf)
338 fn flush(&mut self) -> io::Result<()> {
339 self.0.lock().unwrap().flush()
342 let buf = BufWriter::default();
343 let output = buf.clone();
348 je.fluent_bundle.clone(),
349 je.fallback_bundle.clone(),
354 .ui_testing(je.ui_testing)
355 .emit_diagnostic(diag);
356 let output = Arc::try_unwrap(output.0).unwrap().into_inner().unwrap();
357 let output = String::from_utf8(output).unwrap();
359 let translated_message = je.translate_messages(&diag.message, &args);
361 message: translated_message.to_string(),
362 code: DiagnosticCode::map_opt_string(diag.code.clone(), je),
363 level: diag.level.to_str(),
364 spans: DiagnosticSpan::from_multispan(&diag.span, &args, je),
368 .map(|c| Diagnostic::from_sub_diagnostic(c, &args, je))
371 rendered: Some(output),
375 fn from_sub_diagnostic(
376 diag: &SubDiagnostic,
377 args: &FluentArgs<'_>,
380 let translated_message = je.translate_messages(&diag.message, args);
382 message: translated_message.to_string(),
384 level: diag.level.to_str(),
388 .map(|sp| DiagnosticSpan::from_multispan(sp, args, je))
389 .unwrap_or_else(|| DiagnosticSpan::from_multispan(&diag.span, args, je)),
396 impl DiagnosticSpan {
399 suggestion: Option<(&String, Applicability)>,
400 args: &FluentArgs<'_>,
402 ) -> DiagnosticSpan {
406 span.label.as_ref().map(|m| je.translate_message(m, args)).map(|m| m.to_string()),
415 label: Option<String>,
416 suggestion: Option<(&String, Applicability)>,
418 ) -> DiagnosticSpan {
419 // obtain the full backtrace from the `macro_backtrace`
420 // helper; in some ways, it'd be better to expand the
421 // backtrace ourselves, but the `macro_backtrace` helper makes
422 // some decision, such as dropping some frames, and I don't
423 // want to duplicate that logic here.
424 let backtrace = span.macro_backtrace();
425 DiagnosticSpan::from_span_full(span, is_primary, label, suggestion, backtrace, je)
431 label: Option<String>,
432 suggestion: Option<(&String, Applicability)>,
433 mut backtrace: impl Iterator<Item = ExpnData>,
435 ) -> DiagnosticSpan {
436 let start = je.sm.lookup_char_pos(span.lo());
437 let end = je.sm.lookup_char_pos(span.hi());
438 let backtrace_step = backtrace.next().map(|bt| {
439 let call_site = Self::from_span_full(bt.call_site, false, None, None, backtrace, je);
440 let def_site_span = Self::from_span_full(
441 je.sm.guess_head_span(bt.def_site),
448 Box::new(DiagnosticSpanMacroExpansion {
450 macro_decl_name: bt.kind.descr(),
456 file_name: je.sm.filename_for_diagnostics(&start.file.name).to_string(),
457 byte_start: start.file.original_relative_byte_pos(span.lo()).0,
458 byte_end: start.file.original_relative_byte_pos(span.hi()).0,
459 line_start: start.line,
461 column_start: start.col.0 + 1,
462 column_end: end.col.0 + 1,
464 text: DiagnosticSpanLine::from_span(span, je),
465 suggested_replacement: suggestion.map(|x| x.0.clone()),
466 suggestion_applicability: suggestion.map(|x| x.1),
467 expansion: backtrace_step,
474 args: &FluentArgs<'_>,
476 ) -> Vec<DiagnosticSpan> {
479 .map(|span_str| Self::from_span_label(span_str, None, args, je))
484 suggestion: &CodeSuggestion,
485 args: &FluentArgs<'_>,
487 ) -> Vec<DiagnosticSpan> {
491 .flat_map(|substitution| {
492 substitution.parts.iter().map(move |suggestion_inner| {
494 SpanLabel { span: suggestion_inner.span, is_primary: true, label: None };
495 DiagnosticSpan::from_span_label(
497 Some((&suggestion_inner.snippet, suggestion.applicability)),
507 impl DiagnosticSpanLine {
508 fn line_from_source_file(
509 sf: &rustc_span::SourceFile,
513 ) -> DiagnosticSpanLine {
515 text: sf.get_line(index).map_or_else(String::new, |l| l.into_owned()),
516 highlight_start: h_start,
517 highlight_end: h_end,
521 /// Creates a list of DiagnosticSpanLines from span - each line with any part
522 /// of `span` gets a DiagnosticSpanLine, with the highlight indicating the
523 /// `span` within the line.
524 fn from_span(span: Span, je: &JsonEmitter) -> Vec<DiagnosticSpanLine> {
528 // We can't get any lines if the source is unavailable.
529 if !je.sm.ensure_source_file_source_present(lines.file.clone()) {
533 let sf = &*lines.file;
538 DiagnosticSpanLine::line_from_source_file(
541 line.start_col.0 + 1,
547 .unwrap_or_else(|_| vec![])
551 impl DiagnosticCode {
552 fn map_opt_string(s: Option<DiagnosticId>, je: &JsonEmitter) -> Option<DiagnosticCode> {
555 DiagnosticId::Error(s) => s,
556 DiagnosticId::Lint { name, .. } => name,
559 je.registry.as_ref().map(|registry| registry.try_find_description(&s)).unwrap();
561 DiagnosticCode { code: s, explanation: je_result.unwrap_or(None) }