compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs

   1 //! Emit diagnostics using the `annotate-snippets` library
   2 //!
   3 //! This is the equivalent of `./emitter.rs` but making use of the
   4 //! [`annotate-snippets`][annotate_snippets] library instead of building the output ourselves.
   5 //!
   6 //! [annotate_snippets]: https://docs.rs/crate/annotate-snippets/
   7
   8 use crate::emitter::FileWithAnnotatedLines;
   9 use crate::snippet::Line;
  10 use crate::{
  11     CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage, Emitter, FluentBundle,
  12     LazyFallbackBundle, Level, MultiSpan, Style, SubDiagnostic,
  13 };
  14 use annotate_snippets::display_list::{DisplayList, FormatOptions};
  15 use annotate_snippets::snippet::*;
  16 use rustc_data_structures::sync::Lrc;
  17 use rustc_error_messages::FluentArgs;
  18 use rustc_span::source_map::SourceMap;
  19 use rustc_span::SourceFile;
  20
  21 /// Generates diagnostics using annotate-snippet
  22 pub struct AnnotateSnippetEmitterWriter {
  23     source_map: Option<Lrc<SourceMap>>,
  24     fluent_bundle: Option<Lrc<FluentBundle>>,
  25     fallback_bundle: LazyFallbackBundle,
  26
  27     /// If true, hides the longer explanation text
  28     short_message: bool,
  29     /// If true, will normalize line numbers with `LL` to prevent noise in UI test diffs.
  30     ui_testing: bool,
  31
  32     macro_backtrace: bool,
  33 }
  34
  35 impl Emitter for AnnotateSnippetEmitterWriter {
  36     /// The entry point for the diagnostics generation
  37     fn emit_diagnostic(&mut self, diag: &Diagnostic) {
  38         let fluent_args = self.to_fluent_args(diag.args());
  39
  40         let mut children = diag.children.clone();
  41         let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
  42
  43         self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
  44             &self.source_map,
  45             &mut primary_span,
  46             &mut children,
  47             &diag.level,
  48             self.macro_backtrace,
  49         );
  50
  51         self.emit_messages_default(
  52             &diag.level,
  53             &diag.message,
  54             &fluent_args,
  55             &diag.code,
  56             &primary_span,
  57             &children,
  58             &suggestions,
  59         );
  60     }
  61
  62     fn source_map(&self) -> Option<&Lrc<SourceMap>> {
  63         self.source_map.as_ref()
  64     }
  65
  66     fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
  67         self.fluent_bundle.as_ref()
  68     }
  69
  70     fn fallback_fluent_bundle(&self) -> &FluentBundle {
  71         &**self.fallback_bundle
  72     }
  73
  74     fn should_show_explain(&self) -> bool {
  75         !self.short_message
  76     }
  77 }
  78
  79 /// Provides the source string for the given `line` of `file`
  80 fn source_string(file: Lrc<SourceFile>, line: &Line) -> String {
  81     file.get_line(line.line_index - 1).map(|a| a.to_string()).unwrap_or_default()
  82 }
  83
  84 /// Maps `Diagnostic::Level` to `snippet::AnnotationType`
  85 fn annotation_type_for_level(level: Level) -> AnnotationType {
  86     match level {
  87         Level::Bug | Level::DelayedBug | Level::Fatal | Level::Error { .. } => {
  88             AnnotationType::Error
  89         }
  90         Level::Warning(_) => AnnotationType::Warning,
  91         Level::Note | Level::OnceNote => AnnotationType::Note,
  92         Level::Help => AnnotationType::Help,
  93         // FIXME(#59346): Not sure how to map this level
  94         Level::FailureNote => AnnotationType::Error,
  95         Level::Allow => panic!("Should not call with Allow"),
  96         Level::Expect(_) => panic!("Should not call with Expect"),
  97     }
  98 }
  99
 100 impl AnnotateSnippetEmitterWriter {
 101     pub fn new(
 102         source_map: Option<Lrc<SourceMap>>,
 103         fluent_bundle: Option<Lrc<FluentBundle>>,
 104         fallback_bundle: LazyFallbackBundle,
 105         short_message: bool,
 106         macro_backtrace: bool,
 107     ) -> Self {
 108         Self {
 109             source_map,
 110             fluent_bundle,
 111             fallback_bundle,
 112             short_message,
 113             ui_testing: false,
 114             macro_backtrace,
 115         }
 116     }
 117
 118     /// Allows to modify `Self` to enable or disable the `ui_testing` flag.
 119     ///
 120     /// If this is set to true, line numbers will be normalized as `LL` in the output.
 121     pub fn ui_testing(mut self, ui_testing: bool) -> Self {
 122         self.ui_testing = ui_testing;
 123         self
 124     }
 125
 126     fn emit_messages_default(
 127         &mut self,
 128         level: &Level,
 129         messages: &[(DiagnosticMessage, Style)],
 130         args: &FluentArgs<'_>,
 131         code: &Option<DiagnosticId>,
 132         msp: &MultiSpan,
 133         _children: &[SubDiagnostic],
 134         _suggestions: &[CodeSuggestion],
 135     ) {
 136         let message = self.translate_messages(messages, args);
 137         if let Some(source_map) = &self.source_map {
 138             // Make sure our primary file comes first
 139             let primary_lo = if let Some(ref primary_span) = msp.primary_span().as_ref() {
 140                 if primary_span.is_dummy() {
 141                     // FIXME(#59346): Not sure when this is the case and what
 142                     // should be done if it happens
 143                     return;
 144                 } else {
 145                     source_map.lookup_char_pos(primary_span.lo())
 146                 }
 147             } else {
 148                 // FIXME(#59346): Not sure when this is the case and what
 149                 // should be done if it happens
 150                 return;
 151             };
 152             let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
 153             if let Ok(pos) =
 154                 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
 155             {
 156                 annotated_files.swap(0, pos);
 157             }
 158             // owned: line source, line index, annotations
 159             type Owned = (String, usize, Vec<crate::snippet::Annotation>);
 160             let filename = source_map.filename_for_diagnostics(&primary_lo.file.name);
 161             let origin = filename.to_string_lossy();
 162             let annotated_files: Vec<Owned> = annotated_files
 163                 .into_iter()
 164                 .flat_map(|annotated_file| {
 165                     let file = annotated_file.file;
 166                     annotated_file
 167                         .lines
 168                         .into_iter()
 169                         .map(|line| {
 170                             (source_string(file.clone(), &line), line.line_index, line.annotations)
 171                         })
 172                         .collect::<Vec<Owned>>()
 173                 })
 174                 .collect();
 175             let snippet = Snippet {
 176                 title: Some(Annotation {
 177                     label: Some(&message),
 178                     id: code.as_ref().map(|c| match c {
 179                         DiagnosticId::Error(val) | DiagnosticId::Lint { name: val, .. } => {
 180                             val.as_str()
 181                         }
 182                     }),
 183                     annotation_type: annotation_type_for_level(*level),
 184                 }),
 185                 footer: vec![],
 186                 opt: FormatOptions { color: true, anonymized_line_numbers: self.ui_testing },
 187                 slices: annotated_files
 188                     .iter()
 189                     .map(|(source, line_index, annotations)| {
 190                         Slice {
 191                             source,
 192                             line_start: *line_index,
 193                             origin: Some(&origin),
 194                             // FIXME(#59346): Not really sure when `fold` should be true or false
 195                             fold: false,
 196                             annotations: annotations
 197                                 .iter()
 198                                 .map(|annotation| SourceAnnotation {
 199                                     range: (annotation.start_col, annotation.end_col),
 200                                     label: annotation.label.as_deref().unwrap_or_default(),
 201                                     annotation_type: annotation_type_for_level(*level),
 202                                 })
 203                                 .collect(),
 204                         }
 205                     })
 206                     .collect(),
 207             };
 208             // FIXME(#59346): Figure out if we can _always_ print to stderr or not.
 209             // `emitter.rs` has the `Destination` enum that lists various possible output
 210             // destinations.
 211             eprintln!("{}", DisplayList::from(snippet))
 212         }
 213         // FIXME(#59346): Is it ok to return None if there's no source_map?
 214     }
 215 }