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::{self, File};
  15 use std::io::prelude::*;
  16 use std::path::Path;
  17
  18 use regex::{Regex, escape};
  19
  20 mod version;
  21 use self::version::Version;
  22
  23 const FEATURE_GROUP_START_PREFIX: &str = "// feature-group-start:";
  24 const FEATURE_GROUP_END_PREFIX: &str = "// feature-group-end";
  25
  26 #[derive(Debug, PartialEq, Clone)]
  27 pub enum Status {
  28     Stable,
  29     Removed,
  30     Unstable,
  31 }
  32
  33 impl fmt::Display for Status {
  34     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  35         let as_str = match *self {
  36             Status::Stable => "stable",
  37             Status::Unstable => "unstable",
  38             Status::Removed => "removed",
  39         };
  40         fmt::Display::fmt(as_str, f)
  41     }
  42 }
  43
  44 #[derive(Debug, Clone)]
  45 pub struct Feature {
  46     pub level: Status,
  47     pub since: Option<Version>,
  48     pub has_gate_test: bool,
  49     pub tracking_issue: Option<u32>,
  50 }
  51
  52 pub type Features = HashMap<String, Feature>;
  53
  54 pub fn check(path: &Path, bad: &mut bool, quiet: bool) {
  55     let mut features = collect_lang_features(path, bad);
  56     assert!(!features.is_empty());
  57
  58     let lib_features = get_and_check_lib_features(path, bad, &features);
  59     assert!(!lib_features.is_empty());
  60
  61     let mut contents = String::new();
  62
  63     super::walk_many(&[&path.join("test/ui"),
  64                        &path.join("test/ui-fulldeps"),
  65                        &path.join("test/compile-fail")],
  66                      &mut |path| super::filter_dirs(path),
  67                      &mut |file| {
  68         let filename = file.file_name().unwrap().to_string_lossy();
  69         if !filename.ends_with(".rs") || filename == "features.rs" ||
  70            filename == "diagnostic_list.rs" {
  71             return;
  72         }
  73
  74         let filen_underscore = filename.replace('-',"_").replace(".rs","");
  75         let filename_is_gate_test = test_filen_gate(&filen_underscore, &mut features);
  76
  77         contents.truncate(0);
  78         t!(t!(File::open(&file), &file).read_to_string(&mut contents));
  79
  80         for (i, line) in contents.lines().enumerate() {
  81             let mut err = |msg: &str| {
  82                 tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
  83             };
  84
  85             let gate_test_str = "gate-test-";
  86
  87             let feature_name = match line.find(gate_test_str) {
  88                 Some(i) => {
  89                     line[i+gate_test_str.len()..].splitn(2, ' ').next().unwrap()
  90                 },
  91                 None => continue,
  92             };
  93             match features.get_mut(feature_name) {
  94                 Some(f) => {
  95                     if filename_is_gate_test {
  96                         err(&format!("The file is already marked as gate test \
  97                                       through its name, no need for a \
  98                                       'gate-test-{}' comment",
  99                                      feature_name));
 100                     }
 101                     f.has_gate_test = true;
 102                 }
 103                 None => {
 104                     err(&format!("gate-test test found referencing a nonexistent feature '{}'",
 105                                  feature_name));
 106                 }
 107             }
 108         }
 109     });
 110
 111     // Only check the number of lang features.
 112     // Obligatory testing for library features is dumb.
 113     let gate_untested = features.iter()
 114                                 .filter(|&(_, f)| f.level == Status::Unstable)
 115                                 .filter(|&(_, f)| !f.has_gate_test)
 116                                 .collect::<Vec<_>>();
 117
 118     for &(name, _) in gate_untested.iter() {
 119         println!("Expected a gate test for the feature '{}'.", name);
 120         println!("Hint: create a failing test file named 'feature-gate-{}.rs'\
 121                 \n      in the 'ui' test suite, with its failures due to\
 122                 \n      missing usage of #![feature({})].", name, name);
 123         println!("Hint: If you already have such a test and don't want to rename it,\
 124                 \n      you can also add a // gate-test-{} line to the test file.",
 125                  name);
 126     }
 127
 128     if !gate_untested.is_empty() {
 129         tidy_error!(bad, "Found {} features without a gate test.", gate_untested.len());
 130     }
 131
 132     if *bad {
 133         return;
 134     }
 135     if quiet {
 136         println!("* {} features", features.len());
 137         return;
 138     }
 139
 140     let mut lines = Vec::new();
 141     lines.extend(format_features(&features, "lang"));
 142     lines.extend(format_features(&lib_features, "lib"));
 143
 144     lines.sort();
 145     for line in lines {
 146         println!("* {}", line);
 147     }
 148 }
 149
 150 fn format_features<'a>(features: &'a Features, family: &'a str) -> impl Iterator<Item=String> + 'a {
 151     features.iter().map(move |(name, feature)| {
 152         format!("{:<32} {:<8} {:<12} {:<8}",
 153                 name,
 154                 family,
 155                 feature.level,
 156                 feature.since.as_ref().map_or("None".to_owned(),
 157                                               |since| since.to_string()))
 158     })
 159 }
 160
 161 fn find_attr_val<'a>(line: &'a str, attr: &str) -> Option<&'a str> {
 162     let r = Regex::new(&format!(r#"{}\s*=\s*"([^"]*)""#, escape(attr)))
 163         .expect("malformed regex for find_attr_val");
 164     r.captures(line)
 165         .and_then(|c| c.get(1))
 166         .map(|m| m.as_str())
 167 }
 168
 169 #[test]
 170 fn test_find_attr_val() {
 171     let s = r#"#[unstable(feature = "checked_duration_since", issue = "58402")]"#;
 172     assert_eq!(find_attr_val(s, "feature"), Some("checked_duration_since"));
 173     assert_eq!(find_attr_val(s, "issue"), Some("58402"));
 174     assert_eq!(find_attr_val(s, "since"), None);
 175 }
 176
 177 fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
 178     if filen_underscore.starts_with("feature_gate") {
 179         for (n, f) in features.iter_mut() {
 180             if filen_underscore == format!("feature_gate_{}", n) {
 181                 f.has_gate_test = true;
 182                 return true;
 183             }
 184         }
 185     }
 186     return false;
 187 }
 188
 189 pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
 190     let contents = t!(fs::read_to_string(base_src_path.join("libsyntax/feature_gate.rs")));
 191
 192     // We allow rustc-internal features to omit a tracking issue.
 193     // To make tidy accept omitting a tracking issue, group the list of features
 194     // without one inside `// no tracking issue START` and `// no tracking issue END`.
 195     let mut next_feature_omits_tracking_issue = false;
 196
 197     let mut next_feature_group = None;
 198     let mut prev_since = None;
 199
 200     contents.lines().zip(1..)
 201         .filter_map(|(line, line_number)| {
 202             let line = line.trim();
 203
 204             // Within START and END, the tracking issue can be omitted.
 205             match line {
 206                 "// no tracking issue START" => {
 207                     next_feature_omits_tracking_issue = true;
 208                     return None;
 209                 }
 210                 "// no tracking issue END" => {
 211                     next_feature_omits_tracking_issue = false;
 212                     return None;
 213                 }
 214                 _ => {}
 215             }
 216
 217             if line.starts_with(FEATURE_GROUP_START_PREFIX) {
 218                 if next_feature_group.is_some() {
 219                     tidy_error!(
 220                         bad,
 221                         // ignore-tidy-linelength
 222                         "libsyntax/feature_gate.rs:{}: new feature group is started without ending the previous one",
 223                         line_number,
 224                     );
 225                 }
 226
 227                 let group = line.trim_start_matches(FEATURE_GROUP_START_PREFIX).trim();
 228                 next_feature_group = Some(group.to_owned());
 229                 prev_since = None;
 230                 return None;
 231             } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
 232                 next_feature_group = None;
 233                 prev_since = None;
 234                 return None;
 235             }
 236
 237             let mut parts = line.split(',');
 238             let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
 239                 Some("active") => Status::Unstable,
 240                 Some("removed") => Status::Removed,
 241                 Some("accepted") => Status::Stable,
 242                 _ => return None,
 243             };
 244             let name = parts.next().unwrap().trim();
 245
 246             let since_str = parts.next().unwrap().trim().trim_matches('"');
 247             let since = match since_str.parse() {
 248                 Ok(since) => Some(since),
 249                 Err(err) => {
 250                     tidy_error!(
 251                         bad,
 252                         "libsyntax/feature_gate.rs:{}: failed to parse since: {} ({})",
 253                         line_number,
 254                         since_str,
 255                         err,
 256                     );
 257                     None
 258                 }
 259             };
 260             if next_feature_group.is_some() {
 261                 if prev_since > since {
 262                     tidy_error!(
 263                         bad,
 264                         "libsyntax/feature_gate.rs:{}: feature {} is not sorted by since",
 265                         line_number,
 266                         name,
 267                     );
 268                 }
 269                 prev_since = since.clone();
 270             }
 271
 272             let issue_str = parts.next().unwrap().trim();
 273             let tracking_issue = if issue_str.starts_with("None") {
 274                 if level == Status::Unstable && !next_feature_omits_tracking_issue {
 275                     *bad = true;
 276                     tidy_error!(
 277                         bad,
 278                         "libsyntax/feature_gate.rs:{}: no tracking issue for feature {}",
 279                         line_number,
 280                         name,
 281                     );
 282                 }
 283                 None
 284             } else {
 285                 let s = issue_str.split('(').nth(1).unwrap().split(')').nth(0).unwrap();
 286                 Some(s.parse().unwrap())
 287             };
 288             Some((name.to_owned(),
 289                 Feature {
 290                     level,
 291                     since,
 292                     has_gate_test: false,
 293                     tracking_issue,
 294                 }))
 295         })
 296         .collect()
 297 }
 298
 299 pub fn collect_lib_features(base_src_path: &Path) -> Features {
 300     let mut lib_features = Features::new();
 301
 302     // This library feature is defined in the `compiler_builtins` crate, which
 303     // has been moved out-of-tree. Now it can no longer be auto-discovered by
 304     // `tidy`, because we need to filter out its (submodule) directory. Manually
 305     // add it to the set of known library features so we can still generate docs.
 306     lib_features.insert("compiler_builtins_lib".to_owned(), Feature {
 307         level: Status::Unstable,
 308         since: None,
 309         has_gate_test: false,
 310         tracking_issue: None,
 311     });
 312
 313     map_lib_features(base_src_path,
 314                      &mut |res, _, _| {
 315         if let Ok((name, feature)) = res {
 316             if lib_features.contains_key(name) {
 317                 return;
 318             }
 319             lib_features.insert(name.to_owned(), feature);
 320         }
 321     });
 322    lib_features
 323 }
 324
 325 fn get_and_check_lib_features(base_src_path: &Path,
 326                               bad: &mut bool,
 327                               lang_features: &Features) -> Features {
 328     let mut lib_features = Features::new();
 329     map_lib_features(base_src_path,
 330                      &mut |res, file, line| {
 331             match res {
 332                 Ok((name, f)) => {
 333                     let mut check_features = |f: &Feature, list: &Features, display: &str| {
 334                         if let Some(ref s) = list.get(name) {
 335                             if f.tracking_issue != s.tracking_issue {
 336                                 tidy_error!(bad,
 337                                             "{}:{}: mismatches the `issue` in {}",
 338                                             file.display(),
 339                                             line,
 340                                             display);
 341                             }
 342                         }
 343                     };
 344                     check_features(&f, &lang_features, "corresponding lang feature");
 345                     check_features(&f, &lib_features, "previous");
 346                     lib_features.insert(name.to_owned(), f);
 347                 },
 348                 Err(msg) => {
 349                     tidy_error!(bad, "{}:{}: {}", file.display(), line, msg);
 350                 },
 351             }
 352
 353     });
 354     lib_features
 355 }
 356
 357 fn map_lib_features(base_src_path: &Path,
 358                     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize)) {
 359     let mut contents = String::new();
 360     super::walk(base_src_path,
 361                 &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
 362                 &mut |file| {
 363         let filename = file.file_name().unwrap().to_string_lossy();
 364         if !filename.ends_with(".rs") || filename == "features.rs" ||
 365            filename == "diagnostic_list.rs" {
 366             return;
 367         }
 368
 369         contents.truncate(0);
 370         t!(t!(File::open(&file), &file).read_to_string(&mut contents));
 371
 372         let mut becoming_feature: Option<(String, Feature)> = None;
 373         for (i, line) in contents.lines().enumerate() {
 374             macro_rules! err {
 375                 ($msg:expr) => {{
 376                     mf(Err($msg), file, i + 1);
 377                     continue;
 378                 }};
 379             };
 380             if let Some((ref name, ref mut f)) = becoming_feature {
 381                 if f.tracking_issue.is_none() {
 382                     f.tracking_issue = find_attr_val(line, "issue")
 383                     .map(|s| s.parse().unwrap());
 384                 }
 385                 if line.ends_with(']') {
 386                     mf(Ok((name, f.clone())), file, i + 1);
 387                 } else if !line.ends_with(',') && !line.ends_with('\\') {
 388                     // We need to bail here because we might have missed the
 389                     // end of a stability attribute above because the ']'
 390                     // might not have been at the end of the line.
 391                     // We could then get into the very unfortunate situation that
 392                     // we continue parsing the file assuming the current stability
 393                     // attribute has not ended, and ignoring possible feature
 394                     // attributes in the process.
 395                     err!("malformed stability attribute");
 396                 } else {
 397                     continue;
 398                 }
 399             }
 400             becoming_feature = None;
 401             if line.contains("rustc_const_unstable(") {
 402                 // `const fn` features are handled specially.
 403                 let feature_name = match find_attr_val(line, "feature") {
 404                     Some(name) => name,
 405                     None => err!("malformed stability attribute: missing `feature` key"),
 406                 };
 407                 let feature = Feature {
 408                     level: Status::Unstable,
 409                     since: None,
 410                     has_gate_test: false,
 411                     // FIXME(#57563): #57563 is now used as a common tracking issue,
 412                     // although we would like to have specific tracking issues for each
 413                     // `rustc_const_unstable` in the future.
 414                     tracking_issue: Some(57563),
 415                 };
 416                 mf(Ok((feature_name, feature)), file, i + 1);
 417                 continue;
 418             }
 419             let level = if line.contains("[unstable(") {
 420                 Status::Unstable
 421             } else if line.contains("[stable(") {
 422                 Status::Stable
 423             } else {
 424                 continue;
 425             };
 426             let feature_name = match find_attr_val(line, "feature") {
 427                 Some(name) => name,
 428                 None => err!("malformed stability attribute: missing `feature` key"),
 429             };
 430             let since = match find_attr_val(line, "since").map(|x| x.parse()) {
 431                 Some(Ok(since)) => Some(since),
 432                 Some(Err(_err)) => {
 433                     err!("malformed stability attribute: can't parse `since` key");
 434                 },
 435                 None if level == Status::Stable => {
 436                     err!("malformed stability attribute: missing the `since` key");
 437                 }
 438                 None => None,
 439             };
 440             let tracking_issue = find_attr_val(line, "issue").map(|s| s.parse().unwrap());
 441
 442             let feature = Feature {
 443                 level,
 444                 since,
 445                 has_gate_test: false,
 446                 tracking_issue,
 447             };
 448             if line.contains(']') {
 449                 mf(Ok((feature_name, feature)), file, i + 1);
 450             } else {
 451                 becoming_feature = Some((feature_name.to_owned(), feature));
 452             }
 453         }
 454     });
 455 }