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
  55 pub type Features = HashMap<String, Feature>;
  56
  57 pub struct CollectedFeatures {
  58     pub lib: Features,
  59     pub lang: Features,
  60 }
  61
  62 // Currently only used for unstable book generation
  63 pub fn collect_lib_features(base_src_path: &Path) -> Features {
  64     let mut lib_features = Features::new();
  65
  66     map_lib_features(base_src_path, &mut |res, _, _| {
  67         if let Ok((name, feature)) = res {
  68             lib_features.insert(name.to_owned(), feature);
  69         }
  70     });
  71     lib_features
  72 }
  73
  74 pub fn check(path: &Path, bad: &mut bool, verbose: bool) -> CollectedFeatures {
  75     let mut features = collect_lang_features(path, bad);
  76     assert!(!features.is_empty());
  77
  78     let lib_features = get_and_check_lib_features(path, bad, &features);
  79     assert!(!lib_features.is_empty());
  80
  81     super::walk_many(
  82         &[&path.join("test/ui"), &path.join("test/ui-fulldeps"), &path.join("test/compile-fail")],
  83         &mut |path| super::filter_dirs(path),
  84         &mut |entry, contents| {
  85             let file = entry.path();
  86             let filename = file.file_name().unwrap().to_string_lossy();
  87             if !filename.ends_with(".rs")
  88                 || filename == "features.rs"
  89                 || filename == "diagnostic_list.rs"
  90             {
  91                 return;
  92             }
  93
  94             let filen_underscore = filename.replace('-', "_").replace(".rs", "");
  95             let filename_is_gate_test = test_filen_gate(&filen_underscore, &mut features);
  96
  97             for (i, line) in contents.lines().enumerate() {
  98                 let mut err = |msg: &str| {
  99                     tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
 100                 };
 101
 102                 let gate_test_str = "gate-test-";
 103
 104                 let feature_name = match line.find(gate_test_str) {
 105                     Some(i) => line[i + gate_test_str.len()..].splitn(2, ' ').next().unwrap(),
 106                     None => continue,
 107                 };
 108                 match features.get_mut(feature_name) {
 109                     Some(f) => {
 110                         if filename_is_gate_test {
 111                             err(&format!(
 112                                 "The file is already marked as gate test \
 113                                       through its name, no need for a \
 114                                       'gate-test-{}' comment",
 115                                 feature_name
 116                             ));
 117                         }
 118                         f.has_gate_test = true;
 119                     }
 120                     None => {
 121                         err(&format!(
 122                             "gate-test test found referencing a nonexistent feature '{}'",
 123                             feature_name
 124                         ));
 125                     }
 126                 }
 127             }
 128         },
 129     );
 130
 131     // Only check the number of lang features.
 132     // Obligatory testing for library features is dumb.
 133     let gate_untested = features
 134         .iter()
 135         .filter(|&(_, f)| f.level == Status::Unstable)
 136         .filter(|&(_, f)| !f.has_gate_test)
 137         .collect::<Vec<_>>();
 138
 139     for &(name, _) in gate_untested.iter() {
 140         println!("Expected a gate test for the feature '{}'.", name);
 141         println!(
 142             "Hint: create a failing test file named 'feature-gate-{}.rs'\
 143                 \n      in the 'ui' test suite, with its failures due to\
 144                 \n      missing usage of `#![feature({})]`.",
 145             name, name
 146         );
 147         println!(
 148             "Hint: If you already have such a test and don't want to rename it,\
 149                 \n      you can also add a // gate-test-{} line to the test file.",
 150             name
 151         );
 152     }
 153
 154     if !gate_untested.is_empty() {
 155         tidy_error!(bad, "Found {} features without a gate test.", gate_untested.len());
 156     }
 157
 158     if *bad {
 159         return CollectedFeatures { lib: lib_features, lang: features };
 160     }
 161
 162     if verbose {
 163         let mut lines = Vec::new();
 164         lines.extend(format_features(&features, "lang"));
 165         lines.extend(format_features(&lib_features, "lib"));
 166
 167         lines.sort();
 168         for line in lines {
 169             println!("* {}", line);
 170         }
 171     } else {
 172         println!("* {} features", features.len());
 173     }
 174
 175     CollectedFeatures { lib: lib_features, lang: features }
 176 }
 177
 178 fn format_features<'a>(
 179     features: &'a Features,
 180     family: &'a str,
 181 ) -> impl Iterator<Item = String> + 'a {
 182     features.iter().map(move |(name, feature)| {
 183         format!(
 184             "{:<32} {:<8} {:<12} {:<8}",
 185             name,
 186             family,
 187             feature.level,
 188             feature.since.map_or("None".to_owned(), |since| since.to_string())
 189         )
 190     })
 191 }
 192
 193 fn find_attr_val<'a>(line: &'a str, attr: &str) -> Option<&'a str> {
 194     lazy_static::lazy_static! {
 195         static ref ISSUE: Regex = Regex::new(r#"issue\s*=\s*"([^"]*)""#).unwrap();
 196         static ref FEATURE: Regex = Regex::new(r#"feature\s*=\s*"([^"]*)""#).unwrap();
 197         static ref SINCE: Regex = Regex::new(r#"since\s*=\s*"([^"]*)""#).unwrap();
 198     }
 199
 200     let r = match attr {
 201         "issue" => &*ISSUE,
 202         "feature" => &*FEATURE,
 203         "since" => &*SINCE,
 204         _ => unimplemented!("{} not handled", attr),
 205     };
 206
 207     r.captures(line).and_then(|c| c.get(1)).map(|m| m.as_str())
 208 }
 209
 210 fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
 211     let prefix = "feature_gate_";
 212     if filen_underscore.starts_with(prefix) {
 213         for (n, f) in features.iter_mut() {
 214             // Equivalent to filen_underscore == format!("feature_gate_{}", n)
 215             if &filen_underscore[prefix.len()..] == n {
 216                 f.has_gate_test = true;
 217                 return true;
 218             }
 219         }
 220     }
 221     false
 222 }
 223
 224 pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
 225     let mut all = collect_lang_features_in(base_src_path, "active.rs", bad);
 226     all.extend(collect_lang_features_in(base_src_path, "accepted.rs", bad));
 227     all.extend(collect_lang_features_in(base_src_path, "removed.rs", bad));
 228     all
 229 }
 230
 231 fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features {
 232     let path = base.join("librustc_feature").join(file);
 233     let contents = t!(fs::read_to_string(&path));
 234
 235     // We allow rustc-internal features to omit a tracking issue.
 236     // To make tidy accept omitting a tracking issue, group the list of features
 237     // without one inside `// no-tracking-issue` and `// no-tracking-issue-end`.
 238     let mut next_feature_omits_tracking_issue = false;
 239
 240     let mut in_feature_group = false;
 241     let mut prev_since = None;
 242
 243     contents
 244         .lines()
 245         .zip(1..)
 246         .filter_map(|(line, line_number)| {
 247             let line = line.trim();
 248
 249             // Within -start and -end, the tracking issue can be omitted.
 250             match line {
 251                 "// no-tracking-issue-start" => {
 252                     next_feature_omits_tracking_issue = true;
 253                     return None;
 254                 }
 255                 "// no-tracking-issue-end" => {
 256                     next_feature_omits_tracking_issue = false;
 257                     return None;
 258                 }
 259                 _ => {}
 260             }
 261
 262             if line.starts_with(FEATURE_GROUP_START_PREFIX) {
 263                 if in_feature_group {
 264                     tidy_error!(
 265                         bad,
 266                         "{}:{}: \
 267                         new feature group is started without ending the previous one",
 268                         path.display(),
 269                         line_number,
 270                     );
 271                 }
 272
 273                 in_feature_group = true;
 274                 prev_since = None;
 275                 return None;
 276             } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
 277                 in_feature_group = false;
 278                 prev_since = None;
 279                 return None;
 280             }
 281
 282             let mut parts = line.split(',');
 283             let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
 284                 Some("active") => Status::Unstable,
 285                 Some("removed") => Status::Removed,
 286                 Some("accepted") => Status::Stable,
 287                 _ => return None,
 288             };
 289             let name = parts.next().unwrap().trim();
 290
 291             let since_str = parts.next().unwrap().trim().trim_matches('"');
 292             let since = match since_str.parse() {
 293                 Ok(since) => Some(since),
 294                 Err(err) => {
 295                     tidy_error!(
 296                         bad,
 297                         "{}:{}: failed to parse since: {} ({:?})",
 298                         path.display(),
 299                         line_number,
 300                         since_str,
 301                         err,
 302                     );
 303                     None
 304                 }
 305             };
 306             if in_feature_group {
 307                 if prev_since > since {
 308                     tidy_error!(
 309                         bad,
 310                         "{}:{}: feature {} is not sorted by \"since\" (version number)",
 311                         path.display(),
 312                         line_number,
 313                         name,
 314                     );
 315                 }
 316                 prev_since = since;
 317             }
 318
 319             let issue_str = parts.next().unwrap().trim();
 320             let tracking_issue = if issue_str.starts_with("None") {
 321                 if level == Status::Unstable && !next_feature_omits_tracking_issue {
 322                     *bad = true;
 323                     tidy_error!(
 324                         bad,
 325                         "{}:{}: no tracking issue for feature {}",
 326                         path.display(),
 327                         line_number,
 328                         name,
 329                     );
 330                 }
 331                 None
 332             } else {
 333                 let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
 334                 Some(s.parse().unwrap())
 335             };
 336             Some((name.to_owned(), Feature { level, since, has_gate_test: false, tracking_issue }))
 337         })
 338         .collect()
 339 }
 340
 341 fn get_and_check_lib_features(
 342     base_src_path: &Path,
 343     bad: &mut bool,
 344     lang_features: &Features,
 345 ) -> Features {
 346     let mut lib_features = Features::new();
 347     map_lib_features(base_src_path, &mut |res, file, line| match res {
 348         Ok((name, f)) => {
 349             let mut check_features = |f: &Feature, list: &Features, display: &str| {
 350                 if let Some(ref s) = list.get(name) {
 351                     if f.tracking_issue != s.tracking_issue && f.level != Status::Stable {
 352                         tidy_error!(
 353                             bad,
 354                             "{}:{}: mismatches the `issue` in {}",
 355                             file.display(),
 356                             line,
 357                             display
 358                         );
 359                     }
 360                 }
 361             };
 362             check_features(&f, &lang_features, "corresponding lang feature");
 363             check_features(&f, &lib_features, "previous");
 364             lib_features.insert(name.to_owned(), f);
 365         }
 366         Err(msg) => {
 367             tidy_error!(bad, "{}:{}: {}", file.display(), line, msg);
 368         }
 369     });
 370     lib_features
 371 }
 372
 373 fn map_lib_features(
 374     base_src_path: &Path,
 375     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize),
 376 ) {
 377     super::walk(
 378         base_src_path,
 379         &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
 380         &mut |entry, contents| {
 381             let file = entry.path();
 382             let filename = file.file_name().unwrap().to_string_lossy();
 383             if !filename.ends_with(".rs")
 384                 || filename == "features.rs"
 385                 || filename == "diagnostic_list.rs"
 386                 || filename == "error_codes.rs"
 387             {
 388                 return;
 389             }
 390
 391             // This is an early exit -- all the attributes we're concerned with must contain this:
 392             // * rustc_const_unstable(
 393             // * unstable(
 394             // * stable(
 395             if !contents.contains("stable(") {
 396                 return;
 397             }
 398
 399             let handle_issue_none = |s| match s {
 400                 "none" => None,
 401                 issue => {
 402                     let n = issue.parse().expect("issue number is not a valid integer");
 403                     assert_ne!(n, 0, "\"none\" should be used when there is no issue, not \"0\"");
 404                     NonZeroU32::new(n)
 405                 }
 406             };
 407             let mut becoming_feature: Option<(&str, Feature)> = None;
 408             let mut iter_lines = contents.lines().enumerate().peekable();
 409             while let Some((i, line)) = iter_lines.next() {
 410                 macro_rules! err {
 411                     ($msg:expr) => {{
 412                         mf(Err($msg), file, i + 1);
 413                         continue;
 414                     }};
 415                 };
 416                 if let Some((ref name, ref mut f)) = becoming_feature {
 417                     if f.tracking_issue.is_none() {
 418                         f.tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 419                     }
 420                     if line.ends_with(']') {
 421                         mf(Ok((name, f.clone())), file, i + 1);
 422                     } else if !line.ends_with(',') && !line.ends_with('\\') && !line.ends_with('"')
 423                     {
 424                         // We need to bail here because we might have missed the
 425                         // end of a stability attribute above because the ']'
 426                         // might not have been at the end of the line.
 427                         // We could then get into the very unfortunate situation that
 428                         // we continue parsing the file assuming the current stability
 429                         // attribute has not ended, and ignoring possible feature
 430                         // attributes in the process.
 431                         err!("malformed stability attribute");
 432                     } else {
 433                         continue;
 434                     }
 435                 }
 436                 becoming_feature = None;
 437                 if line.contains("rustc_const_unstable(") {
 438                     // `const fn` features are handled specially.
 439                     let feature_name = match find_attr_val(line, "feature") {
 440                         Some(name) => name,
 441                         None => err!("malformed stability attribute: missing `feature` key"),
 442                     };
 443                     let feature = Feature {
 444                         level: Status::Unstable,
 445                         since: None,
 446                         has_gate_test: false,
 447                         // FIXME(#57563): #57563 is now used as a common tracking issue,
 448                         // although we would like to have specific tracking issues for each
 449                         // `rustc_const_unstable` in the future.
 450                         tracking_issue: NonZeroU32::new(57563),
 451                     };
 452                     mf(Ok((feature_name, feature)), file, i + 1);
 453                     continue;
 454                 }
 455                 let level = if line.contains("[unstable(") {
 456                     Status::Unstable
 457                 } else if line.contains("[stable(") {
 458                     Status::Stable
 459                 } else {
 460                     continue;
 461                 };
 462                 let feature_name = match find_attr_val(line, "feature")
 463                     .or_else(|| iter_lines.peek().and_then(|next| find_attr_val(next.1, "feature")))
 464                 {
 465                     Some(name) => name,
 466                     None => err!("malformed stability attribute: missing `feature` key"),
 467                 };
 468                 let since = match find_attr_val(line, "since").map(|x| x.parse()) {
 469                     Some(Ok(since)) => Some(since),
 470                     Some(Err(_err)) => {
 471                         err!("malformed stability attribute: can't parse `since` key");
 472                     }
 473                     None if level == Status::Stable => {
 474                         err!("malformed stability attribute: missing the `since` key");
 475                     }
 476                     None => None,
 477                 };
 478                 let tracking_issue = find_attr_val(line, "issue").and_then(handle_issue_none);
 479
 480                 let feature = Feature { level, since, has_gate_test: false, tracking_issue };
 481                 if line.contains(']') {
 482                     mf(Ok((feature_name, feature)), file, i + 1);
 483                 } else {
 484                     becoming_feature = Some((feature_name, feature));
 485                 }
 486             }
 487         },
 488     );
 489 }