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