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