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 feature name.
  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             &src_path.join("test/rustdoc"),
 101         ],
 102         &mut |path| super::filter_dirs(path),
 103         &mut |entry, contents| {
 104             let file = entry.path();
 105             let filename = file.file_name().unwrap().to_string_lossy();
 106             if !filename.ends_with(".rs")
 107                 || filename == "features.rs"
 108                 || filename == "diagnostic_list.rs"
 109             {
 110                 return;
 111             }
 112
 113             let filen_underscore = filename.replace('-', "_").replace(".rs", "");
 114             let filename_is_gate_test = test_filen_gate(&filen_underscore, &mut features);
 115
 116             for (i, line) in contents.lines().enumerate() {
 117                 let mut err = |msg: &str| {
 118                     tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
 119                 };
 120
 121                 let gate_test_str = "gate-test-";
 122
 123                 let feature_name = match line.find(gate_test_str) {
 124                     // NB: the `splitn` always succeeds, even if the delimiter is not present.
 125                     Some(i) => line[i + gate_test_str.len()..].splitn(2, ' ').next().unwrap(),
 126                     None => continue,
 127                 };
 128                 match features.get_mut(feature_name) {
 129                     Some(f) => {
 130                         if filename_is_gate_test {
 131                             err(&format!(
 132                                 "The file is already marked as gate test \
 133                                       through its name, no need for a \
 134                                       'gate-test-{}' comment",
 135                                 feature_name
 136                             ));
 137                         }
 138                         f.has_gate_test = true;
 139                     }
 140                     None => {
 141                         err(&format!(
 142                             "gate-test test found referencing a nonexistent feature '{}'",
 143                             feature_name
 144                         ));
 145                     }
 146                 }
 147             }
 148         },
 149     );
 150
 151     // Only check the number of lang features.
 152     // Obligatory testing for library features is dumb.
 153     let gate_untested = features
 154         .iter()
 155         .filter(|&(_, f)| f.level == Status::Unstable)
 156         .filter(|&(_, f)| !f.has_gate_test)
 157         .collect::<Vec<_>>();
 158
 159     for &(name, _) in gate_untested.iter() {
 160         println!("Expected a gate test for the feature '{name}'.");
 161         println!(
 162             "Hint: create a failing test file named 'feature-gate-{}.rs'\
 163                 \n      in the 'ui' test suite, with its failures due to\
 164                 \n      missing usage of `#![feature({})]`.",
 165             name, name
 166         );
 167         println!(
 168             "Hint: If you already have such a test and don't want to rename it,\
 169                 \n      you can also add a // gate-test-{} line to the test file.",
 170             name
 171         );
 172     }
 173
 174     if !gate_untested.is_empty() {
 175         tidy_error!(bad, "Found {} features without a gate test.", gate_untested.len());
 176     }
 177
 178     let (version, channel) = get_version_and_channel(src_path);
 179
 180     let all_features_iter = features
 181         .iter()
 182         .map(|feat| (feat, "lang"))
 183         .chain(lib_features.iter().map(|feat| (feat, "lib")));
 184     for ((feature_name, feature), kind) in all_features_iter {
 185         let since = if let Some(since) = feature.since { since } else { continue };
 186         if since > version && since != Version::CurrentPlaceholder {
 187             tidy_error!(
 188                 bad,
 189                 "The stabilization version {since} of {kind} feature `{feature_name}` is newer than the current {version}"
 190             );
 191         }
 192         if channel == "nightly" && since == version {
 193             tidy_error!(
 194                 bad,
 195                 "The stabilization version {since} of {kind} feature `{feature_name}` is written out but should be {}",
 196                 version::VERSION_PLACEHOLDER
 197             );
 198         }
 199         if channel != "nightly" && since == Version::CurrentPlaceholder {
 200             tidy_error!(
 201                 bad,
 202                 "The placeholder use of {kind} feature `{feature_name}` is not allowed on the {channel} channel",
 203             );
 204         }
 205     }
 206
 207     if *bad {
 208         return CollectedFeatures { lib: lib_features, lang: features };
 209     }
 210
 211     if verbose {
 212         let mut lines = Vec::new();
 213         lines.extend(format_features(&features, "lang"));
 214         lines.extend(format_features(&lib_features, "lib"));
 215
 216         lines.sort();
 217         for line in lines {
 218             println!("* {line}");
 219         }
 220     } else {
 221         println!("* {} features", features.len());
 222     }
 223
 224     CollectedFeatures { lib: lib_features, lang: features }
 225 }
 226
 227 fn get_version_and_channel(src_path: &Path) -> (Version, String) {
 228     let version_str = t!(std::fs::read_to_string(src_path.join("version")));
 229     let version_str = version_str.trim();
 230     let version = t!(std::str::FromStr::from_str(&version_str).map_err(|e| format!("{e:?}")));
 231     let channel_str = t!(std::fs::read_to_string(src_path.join("ci").join("channel")));
 232     (version, channel_str.trim().to_owned())
 233 }
 234
 235 fn format_features<'a>(
 236     features: &'a Features,
 237     family: &'a str,
 238 ) -> impl Iterator<Item = String> + 'a {
 239     features.iter().map(move |(name, feature)| {
 240         format!(
 241             "{:<32} {:<8} {:<12} {:<8}",
 242             name,
 243             family,
 244             feature.level,
 245             feature.since.map_or("None".to_owned(), |since| since.to_string())
 246         )
 247     })
 248 }
 249
 250 fn find_attr_val<'a>(line: &'a str, attr: &str) -> Option<&'a str> {
 251     lazy_static::lazy_static! {
 252         static ref ISSUE: Regex = Regex::new(r#"issue\s*=\s*"([^"]*)""#).unwrap();
 253         static ref FEATURE: Regex = Regex::new(r#"feature\s*=\s*"([^"]*)""#).unwrap();
 254         static ref SINCE: Regex = Regex::new(r#"since\s*=\s*"([^"]*)""#).unwrap();
 255     }
 256
 257     let r = match attr {
 258         "issue" => &*ISSUE,
 259         "feature" => &*FEATURE,
 260         "since" => &*SINCE,
 261         _ => unimplemented!("{attr} not handled"),
 262     };
 263
 264     r.captures(line).and_then(|c| c.get(1)).map(|m| m.as_str())
 265 }
 266
 267 fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
 268     let prefix = "feature_gate_";
 269     if filen_underscore.starts_with(prefix) {
 270         for (n, f) in features.iter_mut() {
 271             // Equivalent to filen_underscore == format!("feature_gate_{n}")
 272             if &filen_underscore[prefix.len()..] == n {
 273                 f.has_gate_test = true;
 274                 return true;
 275             }
 276         }
 277     }
 278     false
 279 }
 280
 281 pub fn collect_lang_features(base_compiler_path: &Path, bad: &mut bool) -> Features {
 282     let mut all = collect_lang_features_in(base_compiler_path, "active.rs", bad);
 283     all.extend(collect_lang_features_in(base_compiler_path, "accepted.rs", bad));
 284     all.extend(collect_lang_features_in(base_compiler_path, "removed.rs", bad));
 285     all
 286 }
 287
 288 fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features {
 289     let path = base.join("rustc_feature").join("src").join(file);
 290     let contents = t!(fs::read_to_string(&path));
 291
 292     // We allow rustc-internal features to omit a tracking issue.
 293     // To make tidy accept omitting a tracking issue, group the list of features
 294     // without one inside `// no-tracking-issue` and `// no-tracking-issue-end`.
 295     let mut next_feature_omits_tracking_issue = false;
 296
 297     let mut in_feature_group = false;
 298     let mut prev_names = vec![];
 299
 300     contents
 301         .lines()
 302         .zip(1..)
 303         .filter_map(|(line, line_number)| {
 304             let line = line.trim();
 305
 306             // Within -start and -end, the tracking issue can be omitted.
 307             match line {
 308                 "// no-tracking-issue-start" => {
 309                     next_feature_omits_tracking_issue = true;
 310                     return None;
 311                 }
 312                 "// no-tracking-issue-end" => {
 313                     next_feature_omits_tracking_issue = false;
 314                     return None;
 315                 }
 316                 _ => {}
 317             }
 318
 319             if line.starts_with(FEATURE_GROUP_START_PREFIX) {
 320                 if in_feature_group {
 321                     tidy_error!(
 322                         bad,
 323                         "{}:{}: \
 324                         new feature group is started without ending the previous one",
 325                         path.display(),
 326                         line_number,
 327                     );
 328                 }
 329
 330                 in_feature_group = true;
 331                 prev_names = vec![];
 332                 return None;
 333             } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
 334                 in_feature_group = false;
 335                 prev_names = vec![];
 336                 return None;
 337             }
 338
 339             let mut parts = line.split(',');
 340             let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
 341                 Some("active") => Status::Unstable,
 342                 Some("incomplete") => Status::Unstable,
 343                 Some("removed") => Status::Removed,
 344                 Some("accepted") => Status::Stable,
 345                 _ => return None,
 346             };
 347             let name = parts.next().unwrap().trim();
 348
 349             let since_str = parts.next().unwrap().trim().trim_matches('"');
 350             let since = match since_str.parse() {
 351                 Ok(since) => Some(since),
 352                 Err(err) => {
 353                     tidy_error!(
 354                         bad,
 355                         "{}:{}: failed to parse since: {} ({:?})",
 356                         path.display(),
 357                         line_number,
 358                         since_str,
 359                         err,
 360                     );
 361                     None
 362                 }
 363             };
 364             if in_feature_group {
 365                 if prev_names.last() > Some(&name) {
 366                     // This assumes the user adds the feature name at the end of the list, as we're
 367                     // not looking ahead.
 368                     let correct_index = match prev_names.binary_search(&name) {
 369                         Ok(_) => {
 370                             // This only occurs when the feature name has already been declared.
 371                             tidy_error!(
 372                                 bad,
 373                                 "{}:{}: duplicate feature {}",
 374                                 path.display(),
 375                                 line_number,
 376                                 name,
 377                             );
 378                             // skip any additional checks for this line
 379                             return None;
 380                         }
 381                         Err(index) => index,
 382                     };
 383
 384                     let correct_placement = if correct_index == 0 {
 385                         "at the beginning of the feature group".to_owned()
 386                     } else if correct_index == prev_names.len() {
 387                         // I don't believe this is reachable given the above assumption, but it
 388                         // doesn't hurt to be safe.
 389                         "at the end of the feature group".to_owned()
 390                     } else {
 391                         format!(
 392                             "between {} and {}",
 393                             prev_names[correct_index - 1],
 394                             prev_names[correct_index],
 395                         )
 396                     };
 397
 398                     tidy_error!(
 399                         bad,
 400                         "{}:{}: feature {} is not sorted by feature name (should be {})",
 401                         path.display(),
 402                         line_number,
 403                         name,
 404                         correct_placement,
 405                     );
 406                 }
 407                 prev_names.push(name);
 408             }
 409
 410             let issue_str = parts.next().unwrap().trim();
 411             let tracking_issue = if issue_str.starts_with("None") {
 412                 if level == Status::Unstable && !next_feature_omits_tracking_issue {
 413                     tidy_error!(
 414                         bad,
 415                         "{}:{}: no tracking issue for feature {}",
 416                         path.display(),
 417                         line_number,
 418                         name,
 419                     );
 420                 }
 421                 None
 422             } else {
 423                 let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
 424                 Some(s.parse().unwrap())
 425             };
 426             Some((name.to_owned(), Feature { level, since, has_gate_test: false, tracking_issue }))
 427         })
 428         .collect()
 429 }
 430
 431 fn get_and_check_lib_features(
 432     base_src_path: &Path,
 433     bad: &mut bool,
 434     lang_features: &Features,
 435 ) -> Features {
 436     let mut lib_features = Features::new();
 437     map_lib_features(base_src_path, &mut |res, file, line| match res {
 438         Ok((name, f)) => {
 439             let mut check_features = |f: &Feature, list: &Features, display: &str| {
 440                 if let Some(ref s) = list.get(name) {
 441                     if f.tracking_issue != s.tracking_issue && f.level != Status::Stable {
 442                         tidy_error!(
 443                             bad,
 444                             "{}:{}: `issue` \"{}\" mismatches the {} `issue` of \"{}\"",
 445                             file.display(),
 446                             line,
 447                             f.tracking_issue_display(),
 448                             display,
 449                             s.tracking_issue_display(),
 450                         );
 451                     }
 452                 }
 453             };
 454             check_features(&f, &lang_features, "corresponding lang feature");
 455             check_features(&f, &lib_features, "previous");
 456             lib_features.insert(name.to_owned(), f);
 457         }
 458         Err(msg) => {
 459             tidy_error!(bad, "{}:{}: {}", file.display(), line, msg);
 460         }
 461     });
 462     lib_features
 463 }
 464
 465 fn map_lib_features(
 466     base_src_path: &Path,
 467     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize),
 468 ) {
 469     super::walk(
 470         base_src_path,
 471         &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
 472         &mut |entry, contents| {
 473             let file = entry.path();
 474             let filename = file.file_name().unwrap().to_string_lossy();
 475             if !filename.ends_with(".rs")
 476                 || filename == "features.rs"
 477                 || filename == "diagnostic_list.rs"
 478                 || filename == "error_codes.rs"
 479             {
 480                 return;
 481             }
 482
 483             // This is an early exit -- all the attributes we're concerned with must contain this:
 484             // * rustc_const_unstable(
 485             // * unstable(
 486             // * stable(
 487             if !contents.contains("stable(") {
 488                 return;
 489             }
 490
 491             let handle_issue_none = |s| match s {
 492                 "none" => None,
 493                 issue => {
 494                     let n = issue.parse().expect("issue number is not a valid integer");
 495                     assert_ne!(n, 0, "\"none\" should be used when there is no issue, not \"0\"");
 496                     NonZeroU32::new(n)
 497                 }
 498             };
 499             let mut becoming_feature: Option<(&str, Feature)> = None;
 500             let mut iter_lines = contents.lines().enumerate().peekable();
 501             while let Some((i, line)) = iter_lines.next() {
 502                 macro_rules! err {
 503                     ($msg:expr) => {{
 504                         mf(Err($msg), file, i + 1);
 505                         continue;
 506                     }};
 507                 }
 508
 509                 lazy_static::lazy_static! {
 510                     static ref COMMENT_LINE: Regex = Regex::new(r"^\s*//").unwrap();
 511                 }
 512                 // exclude commented out lines
 513                 if COMMENT_LINE.is_match(line) {
 514                     continue;
 515                 }
 516
 517                 if let Some((ref name, ref mut f)) = becoming_feature {
 518                     if f.tracking_issue.is_none() {
 519                         f.tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 520                     }
 521                     if line.ends_with(']') {
 522                         mf(Ok((name, f.clone())), file, i + 1);
 523                     } else if !line.ends_with(',') && !line.ends_with('\\') && !line.ends_with('"')
 524                     {
 525                         // We need to bail here because we might have missed the
 526                         // end of a stability attribute above because the ']'
 527                         // might not have been at the end of the line.
 528                         // We could then get into the very unfortunate situation that
 529                         // we continue parsing the file assuming the current stability
 530                         // attribute has not ended, and ignoring possible feature
 531                         // attributes in the process.
 532                         err!("malformed stability attribute");
 533                     } else {
 534                         continue;
 535                     }
 536                 }
 537                 becoming_feature = None;
 538                 if line.contains("rustc_const_unstable(") {
 539                     // `const fn` features are handled specially.
 540                     let feature_name = match find_attr_val(line, "feature") {
 541                         Some(name) => name,
 542                         None => err!("malformed stability attribute: missing `feature` key"),
 543                     };
 544                     let feature = Feature {
 545                         level: Status::Unstable,
 546                         since: None,
 547                         has_gate_test: false,
 548                         tracking_issue: find_attr_val(line, "issue").and_then(handle_issue_none),
 549                     };
 550                     mf(Ok((feature_name, feature)), file, i + 1);
 551                     continue;
 552                 }
 553                 let level = if line.contains("[unstable(") {
 554                     Status::Unstable
 555                 } else if line.contains("[stable(") {
 556                     Status::Stable
 557                 } else {
 558                     continue;
 559                 };
 560                 let feature_name = match find_attr_val(line, "feature")
 561                     .or_else(|| iter_lines.peek().and_then(|next| find_attr_val(next.1, "feature")))
 562                 {
 563                     Some(name) => name,
 564                     None => err!("malformed stability attribute: missing `feature` key"),
 565                 };
 566                 let since = match find_attr_val(line, "since").map(|x| x.parse()) {
 567                     Some(Ok(since)) => Some(since),
 568                     Some(Err(_err)) => {
 569                         err!("malformed stability attribute: can't parse `since` key");
 570                     }
 571                     None if level == Status::Stable => {
 572                         err!("malformed stability attribute: missing the `since` key");
 573                     }
 574                     None => None,
 575                 };
 576                 let tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 577
 578                 let feature = Feature { level, since, has_gate_test: false, tracking_issue };
 579                 if line.contains(']') {
 580                     mf(Ok((feature_name, feature)), file, i + 1);
 581                 } else {
 582                     becoming_feature = Some((feature_name, feature));
 583                 }
 584             }
 585         },
 586     );
 587 }