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::translation::{to_fluent_args, Translate};
  11 use crate::{
  12     CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage, Emitter, FluentBundle,
  13     LazyFallbackBundle, Level, MultiSpan, Style, SubDiagnostic,
  14 };
  15 use annotate_snippets::display_list::{DisplayList, FormatOptions};
  16 use annotate_snippets::snippet::*;
  17 use rustc_data_structures::sync::Lrc;
  18 use rustc_error_messages::FluentArgs;
  19 use rustc_span::source_map::SourceMap;
  20 use rustc_span::SourceFile;
  21
  22 /// Generates diagnostics using annotate-snippet
  23 pub struct AnnotateSnippetEmitterWriter {
  24     source_map: Option<Lrc<SourceMap>>,
  25     fluent_bundle: Option<Lrc<FluentBundle>>,
  26     fallback_bundle: LazyFallbackBundle,
  27
  28     /// If true, hides the longer explanation text
  29     short_message: bool,
  30     /// If true, will normalize line numbers with `LL` to prevent noise in UI test diffs.
  31     ui_testing: bool,
  32
  33     macro_backtrace: bool,
  34 }
  35
  36 impl Translate for AnnotateSnippetEmitterWriter {
  37     fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
  38         self.fluent_bundle.as_ref()
  39     }
  40
  41     fn fallback_fluent_bundle(&self) -> &FluentBundle {
  42         &**self.fallback_bundle
  43     }
  44 }
  45
  46 impl Emitter for AnnotateSnippetEmitterWriter {
  47     /// The entry point for the diagnostics generation
  48     fn emit_diagnostic(&mut self, diag: &Diagnostic) {
  49         let fluent_args = to_fluent_args(diag.args());
  50
  51         let mut children = diag.children.clone();
  52         let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
  53
  54         self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
  55             &self.source_map,
  56             &mut primary_span,
  57             &mut children,
  58             &diag.level,
  59             self.macro_backtrace,
  60         );
  61
  62         self.emit_messages_default(
  63             &diag.level,
  64             &diag.message,
  65             &fluent_args,
  66             &diag.code,
  67             &primary_span,
  68             &children,
  69             &suggestions,
  70         );
  71     }
  72
  73     fn source_map(&self) -> Option<&Lrc<SourceMap>> {
  74         self.source_map.as_ref()
  75     }
  76
  77     fn should_show_explain(&self) -> bool {
  78         !self.short_message
  79     }
  80 }
  81
  82 /// Provides the source string for the given `line` of `file`
  83 fn source_string(file: Lrc<SourceFile>, line: &Line) -> String {
  84     file.get_line(line.line_index - 1).map(|a| a.to_string()).unwrap_or_default()
  85 }
  86
  87 /// Maps `Diagnostic::Level` to `snippet::AnnotationType`
  88 fn annotation_type_for_level(level: Level) -> AnnotationType {
  89     match level {
  90         Level::Bug | Level::DelayedBug | Level::Fatal | Level::Error { .. } => {
  91             AnnotationType::Error
  92         }
  93         Level::Warning(_) => AnnotationType::Warning,
  94         Level::Note | Level::OnceNote => AnnotationType::Note,
  95         Level::Help => AnnotationType::Help,
  96         // FIXME(#59346): Not sure how to map this level
  97         Level::FailureNote => AnnotationType::Error,
  98         Level::Allow => panic!("Should not call with Allow"),
  99         Level::Expect(_) => panic!("Should not call with Expect"),
 100     }
 101 }
 102
 103 impl AnnotateSnippetEmitterWriter {
 104     pub fn new(
 105         source_map: Option<Lrc<SourceMap>>,
 106         fluent_bundle: Option<Lrc<FluentBundle>>,
 107         fallback_bundle: LazyFallbackBundle,
 108         short_message: bool,
 109         macro_backtrace: bool,
 110     ) -> Self {
 111         Self {
 112             source_map,
 113             fluent_bundle,
 114             fallback_bundle,
 115             short_message,
 116             ui_testing: false,
 117             macro_backtrace,
 118         }
 119     }
 120
 121     /// Allows to modify `Self` to enable or disable the `ui_testing` flag.
 122     ///
 123     /// If this is set to true, line numbers will be normalized as `LL` in the output.
 124     pub fn ui_testing(mut self, ui_testing: bool) -> Self {
 125         self.ui_testing = ui_testing;
 126         self
 127     }
 128
 129     fn emit_messages_default(
 130         &mut self,
 131         level: &Level,
 132         messages: &[(DiagnosticMessage, Style)],
 133         args: &FluentArgs<'_>,
 134         code: &Option<DiagnosticId>,
 135         msp: &MultiSpan,
 136         _children: &[SubDiagnostic],
 137         _suggestions: &[CodeSuggestion],
 138     ) {
 139         let message = self.translate_messages(messages, args);
 140         if let Some(source_map) = &self.source_map {
 141             // Make sure our primary file comes first
 142             let primary_lo = if let Some(ref primary_span) = msp.primary_span().as_ref() {
 143                 if primary_span.is_dummy() {
 144                     // FIXME(#59346): Not sure when this is the case and what
 145                     // should be done if it happens
 146                     return;
 147                 } else {
 148                     source_map.lookup_char_pos(primary_span.lo())
 149                 }
 150             } else {
 151                 // FIXME(#59346): Not sure when this is the case and what
 152                 // should be done if it happens
 153                 return;
 154             };
 155             let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
 156             if let Ok(pos) =
 157                 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
 158             {
 159                 annotated_files.swap(0, pos);
 160             }
 161             // owned: line source, line index, annotations
 162             type Owned = (String, usize, Vec<crate::snippet::Annotation>);
 163             let filename = source_map.filename_for_diagnostics(&primary_lo.file.name);
 164             let origin = filename.to_string_lossy();
 165             let annotated_files: Vec<Owned> = annotated_files
 166                 .into_iter()
 167                 .flat_map(|annotated_file| {
 168                     let file = annotated_file.file;
 169                     annotated_file
 170                         .lines
 171                         .into_iter()
 172                         .map(|line| {
 173                             (source_string(file.clone(), &line), line.line_index, line.annotations)
 174                         })
 175                         .collect::<Vec<Owned>>()
 176                 })
 177                 .collect();
 178             let snippet = Snippet {
 179                 title: Some(Annotation {
 180                     label: Some(&message),
 181                     id: code.as_ref().map(|c| match c {
 182                         DiagnosticId::Error(val) | DiagnosticId::Lint { name: val, .. } => {
 183                             val.as_str()
 184                         }
 185                     }),
 186                     annotation_type: annotation_type_for_level(*level),
 187                 }),
 188                 footer: vec![],
 189                 opt: FormatOptions {
 190                     color: true,
 191                     anonymized_line_numbers: self.ui_testing,
 192                     margin: None,
 193                 },
 194                 slices: annotated_files
 195                     .iter()
 196                     .map(|(source, line_index, annotations)| {
 197                         Slice {
 198                             source,
 199                             line_start: *line_index,
 200                             origin: Some(&origin),
 201                             // FIXME(#59346): Not really sure when `fold` should be true or false
 202                             fold: false,
 203                             annotations: annotations
 204                                 .iter()
 205                                 .map(|annotation| SourceAnnotation {
 206                                     range: (annotation.start_col, annotation.end_col),
 207                                     label: annotation.label.as_deref().unwrap_or_default(),
 208                                     annotation_type: annotation_type_for_level(*level),
 209                                 })
 210                                 .collect(),
 211                         }
 212                     })
 213                     .collect(),
 214             };
 215             // FIXME(#59346): Figure out if we can _always_ print to stderr or not.
 216             // `emitter.rs` has the `Destination` enum that lists various possible output
 217             // destinations.
 218             eprintln!("{}", DisplayList::from(snippet))
 219         }
 220         // FIXME(#59346): Is it ok to return None if there's no source_map?
 221     }
 222 }