src/tools/tidy/src/features.rs

   1 //! Tidy check to ensure that unstable features are all in order.
   2 //!
   3 //! This check will ensure properties like:
   4 //!
   5 //! * All stability attributes look reasonably well formed.
   6 //! * The set of library features is disjoint from the set of language features.
   7 //! * Library features have at most one stability level.
   8 //! * Library features have at most one `since` value.
   9 //! * All unstable lang features have tests to ensure they are actually unstable.
  10 //! * Language features in a group are sorted by `since` value.
  11
  12 use std::collections::HashMap;
  13 use std::fmt;
  14 use std::fs;
  15 use std::num::NonZeroU32;
  16 use std::path::Path;
  17
  18 use regex::Regex;
  19
  20 #[cfg(test)]
  21 mod tests;
  22
  23 mod version;
  24 use version::Version;
  25
  26 const FEATURE_GROUP_START_PREFIX: &str = "// feature-group-start";
  27 const FEATURE_GROUP_END_PREFIX: &str = "// feature-group-end";
  28
  29 #[derive(Debug, PartialEq, Clone)]
  30 pub enum Status {
  31     Stable,
  32     Removed,
  33     Unstable,
  34 }
  35
  36 impl fmt::Display for Status {
  37     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  38         let as_str = match *self {
  39             Status::Stable => "stable",
  40             Status::Unstable => "unstable",
  41             Status::Removed => "removed",
  42         };
  43         fmt::Display::fmt(as_str, f)
  44     }
  45 }
  46
  47 #[derive(Debug, Clone)]
  48 pub struct Feature {
  49     pub level: Status,
  50     pub since: Option<Version>,
  51     pub has_gate_test: bool,
  52     pub tracking_issue: Option<NonZeroU32>,
  53 }
  54 impl Feature {
  55     fn tracking_issue_display(&self) -> impl fmt::Display {
  56         match self.tracking_issue {
  57             None => "none".to_string(),
  58             Some(x) => x.to_string(),
  59         }
  60     }
  61 }
  62
  63 pub type Features = HashMap<String, Feature>;
  64
  65 pub struct CollectedFeatures {
  66     pub lib: Features,
  67     pub lang: Features,
  68 }
  69
  70 // Currently only used for unstable book generation
  71 pub fn collect_lib_features(base_src_path: &Path) -> Features {
  72     let mut lib_features = Features::new();
  73
  74     map_lib_features(base_src_path, &mut |res, _, _| {
  75         if let Ok((name, feature)) = res {
  76             lib_features.insert(name.to_owned(), feature);
  77         }
  78     });
  79     lib_features
  80 }
  81
  82 pub fn check(
  83     src_path: &Path,
  84     compiler_path: &Path,
  85     lib_path: &Path,
  86     bad: &mut bool,
  87     verbose: bool,
  88 ) -> CollectedFeatures {
  89     let mut features = collect_lang_features(compiler_path, bad);
  90     assert!(!features.is_empty());
  91
  92     let lib_features = get_and_check_lib_features(lib_path, bad, &features);
  93     assert!(!lib_features.is_empty());
  94
  95     super::walk_many(
  96         &[
  97             &src_path.join("test/ui"),
  98             &src_path.join("test/ui-fulldeps"),
  99             &src_path.join("test/rustdoc-ui"),
 100         ],
 101         &mut |path| super::filter_dirs(path),
 102         &mut |entry, contents| {
 103             let file = entry.path();
 104             let filename = file.file_name().unwrap().to_string_lossy();
 105             if !filename.ends_with(".rs")
 106                 || filename == "features.rs"
 107                 || filename == "diagnostic_list.rs"
 108             {
 109                 return;
 110             }
 111
 112             let filen_underscore = filename.replace('-', "_").replace(".rs", "");
 113             let filename_is_gate_test = test_filen_gate(&filen_underscore, &mut features);
 114
 115             for (i, line) in contents.lines().enumerate() {
 116                 let mut err = |msg: &str| {
 117                     tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
 118                 };
 119
 120                 let gate_test_str = "gate-test-";
 121
 122                 let feature_name = match line.find(gate_test_str) {
 123                     // NB: the `splitn` always succeeds, even if the delimiter is not present.
 124                     Some(i) => line[i + gate_test_str.len()..].splitn(2, ' ').next().unwrap(),
 125                     None => continue,
 126                 };
 127                 match features.get_mut(feature_name) {
 128                     Some(f) => {
 129                         if filename_is_gate_test {
 130                             err(&format!(
 131                                 "The file is already marked as gate test \
 132                                       through its name, no need for a \
 133                                       'gate-test-{}' comment",
 134                                 feature_name
 135                             ));
 136                         }
 137                         f.has_gate_test = true;
 138                     }
 139                     None => {
 140                         err(&format!(
 141                             "gate-test test found referencing a nonexistent feature '{}'",
 142                             feature_name
 143                         ));
 144                     }
 145                 }
 146             }
 147         },
 148     );
 149
 150     // Only check the number of lang features.
 151     // Obligatory testing for library features is dumb.
 152     let gate_untested = features
 153         .iter()
 154         .filter(|&(_, f)| f.level == Status::Unstable)
 155         .filter(|&(_, f)| !f.has_gate_test)
 156         .collect::<Vec<_>>();
 157
 158     for &(name, _) in gate_untested.iter() {
 159         println!("Expected a gate test for the feature '{}'.", name);
 160         println!(
 161             "Hint: create a failing test file named 'feature-gate-{}.rs'\
 162                 \n      in the 'ui' test suite, with its failures due to\
 163                 \n      missing usage of `#![feature({})]`.",
 164             name, name
 165         );
 166         println!(
 167             "Hint: If you already have such a test and don't want to rename it,\
 168                 \n      you can also add a // gate-test-{} line to the test file.",
 169             name
 170         );
 171     }
 172
 173     if !gate_untested.is_empty() {
 174         tidy_error!(bad, "Found {} features without a gate test.", gate_untested.len());
 175     }
 176
 177     if *bad {
 178         return CollectedFeatures { lib: lib_features, lang: features };
 179     }
 180
 181     if verbose {
 182         let mut lines = Vec::new();
 183         lines.extend(format_features(&features, "lang"));
 184         lines.extend(format_features(&lib_features, "lib"));
 185
 186         lines.sort();
 187         for line in lines {
 188             println!("* {}", line);
 189         }
 190     } else {
 191         println!("* {} features", features.len());
 192     }
 193
 194     CollectedFeatures { lib: lib_features, lang: features }
 195 }
 196
 197 fn format_features<'a>(
 198     features: &'a Features,
 199     family: &'a str,
 200 ) -> impl Iterator<Item = String> + 'a {
 201     features.iter().map(move |(name, feature)| {
 202         format!(
 203             "{:<32} {:<8} {:<12} {:<8}",
 204             name,
 205             family,
 206             feature.level,
 207             feature.since.map_or("None".to_owned(), |since| since.to_string())
 208         )
 209     })
 210 }
 211
 212 fn find_attr_val<'a>(line: &'a str, attr: &str) -> Option<&'a str> {
 213     lazy_static::lazy_static! {
 214         static ref ISSUE: Regex = Regex::new(r#"issue\s*=\s*"([^"]*)""#).unwrap();
 215         static ref FEATURE: Regex = Regex::new(r#"feature\s*=\s*"([^"]*)""#).unwrap();
 216         static ref SINCE: Regex = Regex::new(r#"since\s*=\s*"([^"]*)""#).unwrap();
 217     }
 218
 219     let r = match attr {
 220         "issue" => &*ISSUE,
 221         "feature" => &*FEATURE,
 222         "since" => &*SINCE,
 223         _ => unimplemented!("{} not handled", attr),
 224     };
 225
 226     r.captures(line).and_then(|c| c.get(1)).map(|m| m.as_str())
 227 }
 228
 229 fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
 230     let prefix = "feature_gate_";
 231     if filen_underscore.starts_with(prefix) {
 232         for (n, f) in features.iter_mut() {
 233             // Equivalent to filen_underscore == format!("feature_gate_{}", n)
 234             if &filen_underscore[prefix.len()..] == n {
 235                 f.has_gate_test = true;
 236                 return true;
 237             }
 238         }
 239     }
 240     false
 241 }
 242
 243 pub fn collect_lang_features(base_compiler_path: &Path, bad: &mut bool) -> Features {
 244     let mut all = collect_lang_features_in(base_compiler_path, "active.rs", bad);
 245     all.extend(collect_lang_features_in(base_compiler_path, "accepted.rs", bad));
 246     all.extend(collect_lang_features_in(base_compiler_path, "removed.rs", bad));
 247     all
 248 }
 249
 250 fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features {
 251     let path = base.join("rustc_feature").join("src").join(file);
 252     let contents = t!(fs::read_to_string(&path));
 253
 254     // We allow rustc-internal features to omit a tracking issue.
 255     // To make tidy accept omitting a tracking issue, group the list of features
 256     // without one inside `// no-tracking-issue` and `// no-tracking-issue-end`.
 257     let mut next_feature_omits_tracking_issue = false;
 258
 259     let mut in_feature_group = false;
 260     let mut prev_since = None;
 261
 262     contents
 263         .lines()
 264         .zip(1..)
 265         .filter_map(|(line, line_number)| {
 266             let line = line.trim();
 267
 268             // Within -start and -end, the tracking issue can be omitted.
 269             match line {
 270                 "// no-tracking-issue-start" => {
 271                     next_feature_omits_tracking_issue = true;
 272                     return None;
 273                 }
 274                 "// no-tracking-issue-end" => {
 275                     next_feature_omits_tracking_issue = false;
 276                     return None;
 277                 }
 278                 _ => {}
 279             }
 280
 281             if line.starts_with(FEATURE_GROUP_START_PREFIX) {
 282                 if in_feature_group {
 283                     tidy_error!(
 284                         bad,
 285                         "{}:{}: \
 286                         new feature group is started without ending the previous one",
 287                         path.display(),
 288                         line_number,
 289                     );
 290                 }
 291
 292                 in_feature_group = true;
 293                 prev_since = None;
 294                 return None;
 295             } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
 296                 in_feature_group = false;
 297                 prev_since = None;
 298                 return None;
 299             }
 300
 301             let mut parts = line.split(',');
 302             let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
 303                 Some("active") => Status::Unstable,
 304                 Some("removed") => Status::Removed,
 305                 Some("accepted") => Status::Stable,
 306                 _ => return None,
 307             };
 308             let name = parts.next().unwrap().trim();
 309
 310             let since_str = parts.next().unwrap().trim().trim_matches('"');
 311             let since = match since_str.parse() {
 312                 Ok(since) => Some(since),
 313                 Err(err) => {
 314                     tidy_error!(
 315                         bad,
 316                         "{}:{}: failed to parse since: {} ({:?})",
 317                         path.display(),
 318                         line_number,
 319                         since_str,
 320                         err,
 321                     );
 322                     None
 323                 }
 324             };
 325             if in_feature_group {
 326                 if prev_since > since {
 327                     tidy_error!(
 328                         bad,
 329                         "{}:{}: feature {} is not sorted by \"since\" (version number)",
 330                         path.display(),
 331                         line_number,
 332                         name,
 333                     );
 334                 }
 335                 prev_since = since;
 336             }
 337
 338             let issue_str = parts.next().unwrap().trim();
 339             let tracking_issue = if issue_str.starts_with("None") {
 340                 if level == Status::Unstable && !next_feature_omits_tracking_issue {
 341                     tidy_error!(
 342                         bad,
 343                         "{}:{}: no tracking issue for feature {}",
 344                         path.display(),
 345                         line_number,
 346                         name,
 347                     );
 348                 }
 349                 None
 350             } else {
 351                 let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
 352                 Some(s.parse().unwrap())
 353             };
 354             Some((name.to_owned(), Feature { level, since, has_gate_test: false, tracking_issue }))
 355         })
 356         .collect()
 357 }
 358
 359 fn get_and_check_lib_features(
 360     base_src_path: &Path,
 361     bad: &mut bool,
 362     lang_features: &Features,
 363 ) -> Features {
 364     let mut lib_features = Features::new();
 365     map_lib_features(base_src_path, &mut |res, file, line| match res {
 366         Ok((name, f)) => {
 367             let mut check_features = |f: &Feature, list: &Features, display: &str| {
 368                 if let Some(ref s) = list.get(name) {
 369                     if f.tracking_issue != s.tracking_issue && f.level != Status::Stable {
 370                         tidy_error!(
 371                             bad,
 372                             "{}:{}: `issue` \"{}\" mismatches the {} `issue` of \"{}\"",
 373                             file.display(),
 374                             line,
 375                             f.tracking_issue_display(),
 376                             display,
 377                             s.tracking_issue_display(),
 378                         );
 379                     }
 380                 }
 381             };
 382             check_features(&f, &lang_features, "corresponding lang feature");
 383             check_features(&f, &lib_features, "previous");
 384             lib_features.insert(name.to_owned(), f);
 385         }
 386         Err(msg) => {
 387             tidy_error!(bad, "{}:{}: {}", file.display(), line, msg);
 388         }
 389     });
 390     lib_features
 391 }
 392
 393 fn map_lib_features(
 394     base_src_path: &Path,
 395     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize),
 396 ) {
 397     super::walk(
 398         base_src_path,
 399         &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
 400         &mut |entry, contents| {
 401             let file = entry.path();
 402             let filename = file.file_name().unwrap().to_string_lossy();
 403             if !filename.ends_with(".rs")
 404                 || filename == "features.rs"
 405                 || filename == "diagnostic_list.rs"
 406                 || filename == "error_codes.rs"
 407             {
 408                 return;
 409             }
 410
 411             // This is an early exit -- all the attributes we're concerned with must contain this:
 412             // * rustc_const_unstable(
 413             // * unstable(
 414             // * stable(
 415             if !contents.contains("stable(") {
 416                 return;
 417             }
 418
 419             let handle_issue_none = |s| match s {
 420                 "none" => None,
 421                 issue => {
 422                     let n = issue.parse().expect("issue number is not a valid integer");
 423                     assert_ne!(n, 0, "\"none\" should be used when there is no issue, not \"0\"");
 424                     NonZeroU32::new(n)
 425                 }
 426             };
 427             let mut becoming_feature: Option<(&str, Feature)> = None;
 428             let mut iter_lines = contents.lines().enumerate().peekable();
 429             while let Some((i, line)) = iter_lines.next() {
 430                 macro_rules! err {
 431                     ($msg:expr) => {{
 432                         mf(Err($msg), file, i + 1);
 433                         continue;
 434                     }};
 435                 }
 436
 437                 lazy_static::lazy_static! {
 438                     static ref COMMENT_LINE: Regex = Regex::new(r"^\s*//").unwrap();
 439                 }
 440                 // exclude commented out lines
 441                 if COMMENT_LINE.is_match(line) {
 442                     continue;
 443                 }
 444
 445                 if let Some((ref name, ref mut f)) = becoming_feature {
 446                     if f.tracking_issue.is_none() {
 447                         f.tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 448                     }
 449                     if line.ends_with(']') {
 450                         mf(Ok((name, f.clone())), file, i + 1);
 451                     } else if !line.ends_with(',') && !line.ends_with('\\') && !line.ends_with('"')
 452                     {
 453                         // We need to bail here because we might have missed the
 454                         // end of a stability attribute above because the ']'
 455                         // might not have been at the end of the line.
 456                         // We could then get into the very unfortunate situation that
 457                         // we continue parsing the file assuming the current stability
 458                         // attribute has not ended, and ignoring possible feature
 459                         // attributes in the process.
 460                         err!("malformed stability attribute");
 461                     } else {
 462                         continue;
 463                     }
 464                 }
 465                 becoming_feature = None;
 466                 if line.contains("rustc_const_unstable(") {
 467                     // `const fn` features are handled specially.
 468                     let feature_name = match find_attr_val(line, "feature") {
 469                         Some(name) => name,
 470                         None => err!("malformed stability attribute: missing `feature` key"),
 471                     };
 472                     let feature = Feature {
 473                         level: Status::Unstable,
 474                         since: None,
 475                         has_gate_test: false,
 476                         tracking_issue: find_attr_val(line, "issue").and_then(handle_issue_none),
 477                     };
 478                     mf(Ok((feature_name, feature)), file, i + 1);
 479                     continue;
 480                 }
 481                 let level = if line.contains("[unstable(") {
 482                     Status::Unstable
 483                 } else if line.contains("[stable(") {
 484                     Status::Stable
 485                 } else {
 486                     continue;
 487                 };
 488                 let feature_name = match find_attr_val(line, "feature")
 489                     .or_else(|| iter_lines.peek().and_then(|next| find_attr_val(next.1, "feature")))
 490                 {
 491                     Some(name) => name,
 492                     None => err!("malformed stability attribute: missing `feature` key"),
 493                 };
 494                 let since = match find_attr_val(line, "since").map(|x| x.parse()) {
 495                     Some(Ok(since)) => Some(since),
 496                     Some(Err(_err)) => {
 497                         err!("malformed stability attribute: can't parse `since` key");
 498                     }
 499                     None if level == Status::Stable => {
 500                         err!("malformed stability attribute: missing the `since` key");
 501                     }
 502                     None => None,
 503                 };
 504                 let tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 505
 506                 let feature = Feature { level, since, has_gate_test: false, tracking_issue };
 507                 if line.contains(']') {
 508                     mf(Ok((feature_name, feature)), file, i + 1);
 509                 } else {
 510                     becoming_feature = Some((feature_name, feature));
 511                 }
 512             }
 513         },
 514     );
 515 }