compiler/rustc_error_messages/src/lib.rs

   1 #![feature(let_chains)]
   2 #![feature(once_cell)]
   3 #![feature(rustc_attrs)]
   4 #![feature(type_alias_impl_trait)]
   5
   6 use fluent_bundle::FluentResource;
   7 use fluent_syntax::parser::ParserError;
   8 use rustc_data_structures::sync::Lrc;
   9 use rustc_macros::{fluent_messages, Decodable, Encodable};
  10 use rustc_span::Span;
  11 use std::borrow::Cow;
  12 use std::error::Error;
  13 use std::fmt;
  14 use std::fs;
  15 use std::io;
  16 use std::path::{Path, PathBuf};
  17 use tracing::{instrument, trace};
  18
  19 #[cfg(not(parallel_compiler))]
  20 use std::cell::LazyCell as Lazy;
  21 #[cfg(parallel_compiler)]
  22 use std::sync::LazyLock as Lazy;
  23
  24 #[cfg(parallel_compiler)]
  25 use intl_memoizer::concurrent::IntlLangMemoizer;
  26 #[cfg(not(parallel_compiler))]
  27 use intl_memoizer::IntlLangMemoizer;
  28
  29 pub use fluent_bundle::{FluentArgs, FluentError, FluentValue};
  30 pub use unic_langid::{langid, LanguageIdentifier};
  31
  32 // Generates `DEFAULT_LOCALE_RESOURCES` static and `fluent_generated` module.
  33 fluent_messages! {
  34     parser => "../locales/en-US/parser.ftl",
  35     typeck => "../locales/en-US/typeck.ftl",
  36     builtin_macros => "../locales/en-US/builtin_macros.ftl",
  37 }
  38
  39 pub use fluent_generated::{self as fluent, DEFAULT_LOCALE_RESOURCES};
  40
  41 pub type FluentBundle = fluent_bundle::bundle::FluentBundle<FluentResource, IntlLangMemoizer>;
  42
  43 #[cfg(parallel_compiler)]
  44 fn new_bundle(locales: Vec<LanguageIdentifier>) -> FluentBundle {
  45     FluentBundle::new_concurrent(locales)
  46 }
  47
  48 #[cfg(not(parallel_compiler))]
  49 fn new_bundle(locales: Vec<LanguageIdentifier>) -> FluentBundle {
  50     FluentBundle::new(locales)
  51 }
  52
  53 #[derive(Debug)]
  54 pub enum TranslationBundleError {
  55     /// Failed to read from `.ftl` file.
  56     ReadFtl(io::Error),
  57     /// Failed to parse contents of `.ftl` file.
  58     ParseFtl(ParserError),
  59     /// Failed to add `FluentResource` to `FluentBundle`.
  60     AddResource(FluentError),
  61     /// `$sysroot/share/locale/$locale` does not exist.
  62     MissingLocale,
  63     /// Cannot read directory entries of `$sysroot/share/locale/$locale`.
  64     ReadLocalesDir(io::Error),
  65     /// Cannot read directory entry of `$sysroot/share/locale/$locale`.
  66     ReadLocalesDirEntry(io::Error),
  67     /// `$sysroot/share/locale/$locale` is not a directory.
  68     LocaleIsNotDir,
  69 }
  70
  71 impl fmt::Display for TranslationBundleError {
  72     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  73         match self {
  74             TranslationBundleError::ReadFtl(e) => write!(f, "could not read ftl file: {}", e),
  75             TranslationBundleError::ParseFtl(e) => {
  76                 write!(f, "could not parse ftl file: {}", e)
  77             }
  78             TranslationBundleError::AddResource(e) => write!(f, "failed to add resource: {}", e),
  79             TranslationBundleError::MissingLocale => write!(f, "missing locale directory"),
  80             TranslationBundleError::ReadLocalesDir(e) => {
  81                 write!(f, "could not read locales dir: {}", e)
  82             }
  83             TranslationBundleError::ReadLocalesDirEntry(e) => {
  84                 write!(f, "could not read locales dir entry: {}", e)
  85             }
  86             TranslationBundleError::LocaleIsNotDir => {
  87                 write!(f, "`$sysroot/share/locales/$locale` is not a directory")
  88             }
  89         }
  90     }
  91 }
  92
  93 impl Error for TranslationBundleError {
  94     fn source(&self) -> Option<&(dyn Error + 'static)> {
  95         match self {
  96             TranslationBundleError::ReadFtl(e) => Some(e),
  97             TranslationBundleError::ParseFtl(e) => Some(e),
  98             TranslationBundleError::AddResource(e) => Some(e),
  99             TranslationBundleError::MissingLocale => None,
 100             TranslationBundleError::ReadLocalesDir(e) => Some(e),
 101             TranslationBundleError::ReadLocalesDirEntry(e) => Some(e),
 102             TranslationBundleError::LocaleIsNotDir => None,
 103         }
 104     }
 105 }
 106
 107 impl From<(FluentResource, Vec<ParserError>)> for TranslationBundleError {
 108     fn from((_, mut errs): (FluentResource, Vec<ParserError>)) -> Self {
 109         TranslationBundleError::ParseFtl(errs.pop().expect("failed ftl parse with no errors"))
 110     }
 111 }
 112
 113 impl From<Vec<FluentError>> for TranslationBundleError {
 114     fn from(mut errs: Vec<FluentError>) -> Self {
 115         TranslationBundleError::AddResource(
 116             errs.pop().expect("failed adding resource to bundle with no errors"),
 117         )
 118     }
 119 }
 120
 121 /// Returns Fluent bundle with the user's locale resources from
 122 /// `$sysroot/share/locale/$requested_locale/*.ftl`.
 123 ///
 124 /// If `-Z additional-ftl-path` was provided, load that resource and add it  to the bundle
 125 /// (overriding any conflicting messages).
 126 #[instrument(level = "trace")]
 127 pub fn fluent_bundle(
 128     mut user_provided_sysroot: Option<PathBuf>,
 129     mut sysroot_candidates: Vec<PathBuf>,
 130     requested_locale: Option<LanguageIdentifier>,
 131     additional_ftl_path: Option<&Path>,
 132     with_directionality_markers: bool,
 133 ) -> Result<Option<Lrc<FluentBundle>>, TranslationBundleError> {
 134     if requested_locale.is_none() && additional_ftl_path.is_none() {
 135         return Ok(None);
 136     }
 137
 138     let fallback_locale = langid!("en-US");
 139     let requested_fallback_locale = requested_locale.as_ref() == Some(&fallback_locale);
 140
 141     // If there is only `-Z additional-ftl-path`, assume locale is "en-US", otherwise use user
 142     // provided locale.
 143     let locale = requested_locale.clone().unwrap_or(fallback_locale);
 144     trace!(?locale);
 145     let mut bundle = new_bundle(vec![locale]);
 146
 147     // Fluent diagnostics can insert directionality isolation markers around interpolated variables
 148     // indicating that there may be a shift from right-to-left to left-to-right text (or
 149     // vice-versa). These are disabled because they are sometimes visible in the error output, but
 150     // may be worth investigating in future (for example: if type names are left-to-right and the
 151     // surrounding diagnostic messages are right-to-left, then these might be helpful).
 152     bundle.set_use_isolating(with_directionality_markers);
 153
 154     // If the user requests the default locale then don't try to load anything.
 155     if !requested_fallback_locale && let Some(requested_locale) = requested_locale {
 156         let mut found_resources = false;
 157         for sysroot in user_provided_sysroot.iter_mut().chain(sysroot_candidates.iter_mut()) {
 158             sysroot.push("share");
 159             sysroot.push("locale");
 160             sysroot.push(requested_locale.to_string());
 161             trace!(?sysroot);
 162
 163             if !sysroot.exists() {
 164                 trace!("skipping");
 165                 continue;
 166             }
 167
 168             if !sysroot.is_dir() {
 169                 return Err(TranslationBundleError::LocaleIsNotDir);
 170             }
 171
 172             for entry in sysroot.read_dir().map_err(TranslationBundleError::ReadLocalesDir)? {
 173                 let entry = entry.map_err(TranslationBundleError::ReadLocalesDirEntry)?;
 174                 let path = entry.path();
 175                 trace!(?path);
 176                 if path.extension().and_then(|s| s.to_str()) != Some("ftl") {
 177                     trace!("skipping");
 178                     continue;
 179                 }
 180
 181                 let resource_str =
 182                     fs::read_to_string(path).map_err(TranslationBundleError::ReadFtl)?;
 183                 let resource =
 184                     FluentResource::try_new(resource_str).map_err(TranslationBundleError::from)?;
 185                 trace!(?resource);
 186                 bundle.add_resource(resource).map_err(TranslationBundleError::from)?;
 187                 found_resources = true;
 188             }
 189         }
 190
 191         if !found_resources {
 192             return Err(TranslationBundleError::MissingLocale);
 193         }
 194     }
 195
 196     if let Some(additional_ftl_path) = additional_ftl_path {
 197         let resource_str =
 198             fs::read_to_string(additional_ftl_path).map_err(TranslationBundleError::ReadFtl)?;
 199         let resource =
 200             FluentResource::try_new(resource_str).map_err(TranslationBundleError::from)?;
 201         trace!(?resource);
 202         bundle.add_resource_overriding(resource);
 203     }
 204
 205     let bundle = Lrc::new(bundle);
 206     Ok(Some(bundle))
 207 }
 208
 209 /// Type alias for the result of `fallback_fluent_bundle` - a reference-counted pointer to a lazily
 210 /// evaluated fluent bundle.
 211 pub type LazyFallbackBundle = Lrc<Lazy<FluentBundle, impl FnOnce() -> FluentBundle>>;
 212
 213 /// Return the default `FluentBundle` with standard "en-US" diagnostic messages.
 214 #[instrument(level = "trace")]
 215 pub fn fallback_fluent_bundle(
 216     resources: &'static [&'static str],
 217     with_directionality_markers: bool,
 218 ) -> LazyFallbackBundle {
 219     Lrc::new(Lazy::new(move || {
 220         let mut fallback_bundle = new_bundle(vec![langid!("en-US")]);
 221         // See comment in `fluent_bundle`.
 222         fallback_bundle.set_use_isolating(with_directionality_markers);
 223
 224         for resource in resources {
 225             let resource = FluentResource::try_new(resource.to_string())
 226                 .expect("failed to parse fallback fluent resource");
 227             trace!(?resource);
 228             fallback_bundle.add_resource_overriding(resource);
 229         }
 230
 231         fallback_bundle
 232     }))
 233 }
 234
 235 /// Identifier for the Fluent message/attribute corresponding to a diagnostic message.
 236 type FluentId = Cow<'static, str>;
 237
 238 /// Abstraction over a message in a subdiagnostic (i.e. label, note, help, etc) to support both
 239 /// translatable and non-translatable diagnostic messages.
 240 ///
 241 /// Translatable messages for subdiagnostics are typically attributes attached to a larger Fluent
 242 /// message so messages of this type must be combined with a `DiagnosticMessage` (using
 243 /// `DiagnosticMessage::with_subdiagnostic_message`) before rendering. However, subdiagnostics from
 244 /// the `SessionSubdiagnostic` derive refer to Fluent identifiers directly.
 245 #[rustc_diagnostic_item = "SubdiagnosticMessage"]
 246 pub enum SubdiagnosticMessage {
 247     /// Non-translatable diagnostic message.
 248     // FIXME(davidtwco): can a `Cow<'static, str>` be used here?
 249     Str(String),
 250     /// Identifier of a Fluent message. Instances of this variant are generated by the
 251     /// `SessionSubdiagnostic` derive.
 252     FluentIdentifier(FluentId),
 253     /// Attribute of a Fluent message. Needs to be combined with a Fluent identifier to produce an
 254     /// actual translated message. Instances of this variant are generated by the `fluent_messages`
 255     /// macro.
 256     ///
 257     /// <https://projectfluent.org/fluent/guide/attributes.html>
 258     FluentAttr(FluentId),
 259 }
 260
 261 impl SubdiagnosticMessage {
 262     /// Create a `SubdiagnosticMessage` for the provided Fluent attribute.
 263     pub fn attr(id: impl Into<FluentId>) -> Self {
 264         SubdiagnosticMessage::FluentAttr(id.into())
 265     }
 266
 267     /// Create a `SubdiagnosticMessage` for the provided Fluent identifier.
 268     pub fn message(id: impl Into<FluentId>) -> Self {
 269         SubdiagnosticMessage::FluentIdentifier(id.into())
 270     }
 271 }
 272
 273 /// `From` impl that enables existing diagnostic calls to functions which now take
 274 /// `impl Into<SubdiagnosticMessage>` to continue to work as before.
 275 impl<S: Into<String>> From<S> for SubdiagnosticMessage {
 276     fn from(s: S) -> Self {
 277         SubdiagnosticMessage::Str(s.into())
 278     }
 279 }
 280
 281 /// Abstraction over a message in a diagnostic to support both translatable and non-translatable
 282 /// diagnostic messages.
 283 ///
 284 /// Intended to be removed once diagnostics are entirely translatable.
 285 #[derive(Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
 286 #[rustc_diagnostic_item = "DiagnosticMessage"]
 287 pub enum DiagnosticMessage {
 288     /// Non-translatable diagnostic message.
 289     // FIXME(davidtwco): can a `Cow<'static, str>` be used here?
 290     Str(String),
 291     /// Identifier for a Fluent message (with optional attribute) corresponding to the diagnostic
 292     /// message.
 293     ///
 294     /// <https://projectfluent.org/fluent/guide/hello.html>
 295     /// <https://projectfluent.org/fluent/guide/attributes.html>
 296     FluentIdentifier(FluentId, Option<FluentId>),
 297 }
 298
 299 impl DiagnosticMessage {
 300     /// Given a `SubdiagnosticMessage` which may contain a Fluent attribute, create a new
 301     /// `DiagnosticMessage` that combines that attribute with the Fluent identifier of `self`.
 302     ///
 303     /// - If the `SubdiagnosticMessage` is non-translatable then return the message as a
 304     /// `DiagnosticMessage`.
 305     /// - If `self` is non-translatable then return `self`'s message.
 306     pub fn with_subdiagnostic_message(&self, sub: SubdiagnosticMessage) -> Self {
 307         let attr = match sub {
 308             SubdiagnosticMessage::Str(s) => return DiagnosticMessage::Str(s.clone()),
 309             SubdiagnosticMessage::FluentIdentifier(id) => {
 310                 return DiagnosticMessage::FluentIdentifier(id, None);
 311             }
 312             SubdiagnosticMessage::FluentAttr(attr) => attr,
 313         };
 314
 315         match self {
 316             DiagnosticMessage::Str(s) => DiagnosticMessage::Str(s.clone()),
 317             DiagnosticMessage::FluentIdentifier(id, _) => {
 318                 DiagnosticMessage::FluentIdentifier(id.clone(), Some(attr))
 319             }
 320         }
 321     }
 322
 323     /// Returns the `String` contained within the `DiagnosticMessage::Str` variant, assuming that
 324     /// this diagnostic message is of the legacy, non-translatable variety. Panics if this
 325     /// assumption does not hold.
 326     ///
 327     /// Don't use this - it exists to support some places that do comparison with diagnostic
 328     /// strings.
 329     pub fn expect_str(&self) -> &str {
 330         match self {
 331             DiagnosticMessage::Str(s) => s,
 332             _ => panic!("expected non-translatable diagnostic message"),
 333         }
 334     }
 335
 336     /// Create a `DiagnosticMessage` for the provided Fluent identifier.
 337     pub fn new(id: impl Into<FluentId>) -> Self {
 338         DiagnosticMessage::FluentIdentifier(id.into(), None)
 339     }
 340 }
 341
 342 /// `From` impl that enables existing diagnostic calls to functions which now take
 343 /// `impl Into<DiagnosticMessage>` to continue to work as before.
 344 impl<S: Into<String>> From<S> for DiagnosticMessage {
 345     fn from(s: S) -> Self {
 346         DiagnosticMessage::Str(s.into())
 347     }
 348 }
 349
 350 /// A span together with some additional data.
 351 #[derive(Clone, Debug)]
 352 pub struct SpanLabel {
 353     /// The span we are going to include in the final snippet.
 354     pub span: Span,
 355
 356     /// Is this a primary span? This is the "locus" of the message,
 357     /// and is indicated with a `^^^^` underline, versus `----`.
 358     pub is_primary: bool,
 359
 360     /// What label should we attach to this span (if any)?
 361     pub label: Option<DiagnosticMessage>,
 362 }
 363
 364 /// A collection of `Span`s.
 365 ///
 366 /// Spans have two orthogonal attributes:
 367 ///
 368 /// - They can be *primary spans*. In this case they are the locus of
 369 ///   the error, and would be rendered with `^^^`.
 370 /// - They can have a *label*. In this case, the label is written next
 371 ///   to the mark in the snippet when we render.
 372 #[derive(Clone, Debug, Hash, PartialEq, Eq, Encodable, Decodable)]
 373 pub struct MultiSpan {
 374     primary_spans: Vec<Span>,
 375     span_labels: Vec<(Span, DiagnosticMessage)>,
 376 }
 377
 378 impl MultiSpan {
 379     #[inline]
 380     pub fn new() -> MultiSpan {
 381         MultiSpan { primary_spans: vec![], span_labels: vec![] }
 382     }
 383
 384     pub fn from_span(primary_span: Span) -> MultiSpan {
 385         MultiSpan { primary_spans: vec![primary_span], span_labels: vec![] }
 386     }
 387
 388     pub fn from_spans(mut vec: Vec<Span>) -> MultiSpan {
 389         vec.sort();
 390         MultiSpan { primary_spans: vec, span_labels: vec![] }
 391     }
 392
 393     pub fn push_span_label(&mut self, span: Span, label: impl Into<DiagnosticMessage>) {
 394         self.span_labels.push((span, label.into()));
 395     }
 396
 397     /// Selects the first primary span (if any).
 398     pub fn primary_span(&self) -> Option<Span> {
 399         self.primary_spans.first().cloned()
 400     }
 401
 402     /// Returns all primary spans.
 403     pub fn primary_spans(&self) -> &[Span] {
 404         &self.primary_spans
 405     }
 406
 407     /// Returns `true` if any of the primary spans are displayable.
 408     pub fn has_primary_spans(&self) -> bool {
 409         !self.is_dummy()
 410     }
 411
 412     /// Returns `true` if this contains only a dummy primary span with any hygienic context.
 413     pub fn is_dummy(&self) -> bool {
 414         self.primary_spans.iter().all(|sp| sp.is_dummy())
 415     }
 416
 417     /// Replaces all occurrences of one Span with another. Used to move `Span`s in areas that don't
 418     /// display well (like std macros). Returns whether replacements occurred.
 419     pub fn replace(&mut self, before: Span, after: Span) -> bool {
 420         let mut replacements_occurred = false;
 421         for primary_span in &mut self.primary_spans {
 422             if *primary_span == before {
 423                 *primary_span = after;
 424                 replacements_occurred = true;
 425             }
 426         }
 427         for span_label in &mut self.span_labels {
 428             if span_label.0 == before {
 429                 span_label.0 = after;
 430                 replacements_occurred = true;
 431             }
 432         }
 433         replacements_occurred
 434     }
 435
 436     /// Returns the strings to highlight. We always ensure that there
 437     /// is an entry for each of the primary spans -- for each primary
 438     /// span `P`, if there is at least one label with span `P`, we return
 439     /// those labels (marked as primary). But otherwise we return
 440     /// `SpanLabel` instances with empty labels.
 441     pub fn span_labels(&self) -> Vec<SpanLabel> {
 442         let is_primary = |span| self.primary_spans.contains(&span);
 443
 444         let mut span_labels = self
 445             .span_labels
 446             .iter()
 447             .map(|&(span, ref label)| SpanLabel {
 448                 span,
 449                 is_primary: is_primary(span),
 450                 label: Some(label.clone()),
 451             })
 452             .collect::<Vec<_>>();
 453
 454         for &span in &self.primary_spans {
 455             if !span_labels.iter().any(|sl| sl.span == span) {
 456                 span_labels.push(SpanLabel { span, is_primary: true, label: None });
 457             }
 458         }
 459
 460         span_labels
 461     }
 462
 463     /// Returns `true` if any of the span labels is displayable.
 464     pub fn has_span_labels(&self) -> bool {
 465         self.span_labels.iter().any(|(sp, _)| !sp.is_dummy())
 466     }
 467 }
 468
 469 impl From<Span> for MultiSpan {
 470     fn from(span: Span) -> MultiSpan {
 471         MultiSpan::from_span(span)
 472     }
 473 }
 474
 475 impl From<Vec<Span>> for MultiSpan {
 476     fn from(spans: Vec<Span>) -> MultiSpan {
 477         MultiSpan::from_spans(spans)
 478     }
 479 }