1 //! Tidy check to ensure error codes are properly documented and tested.
5 //! 1. We create a list of error codes used by the compiler. Error codes are extracted from `compiler/rustc_error_codes/src/error_codes.rs`.
7 //! 2. We check that the error code has a long-form explanation in `compiler/rustc_error_codes/src/error_codes/`.
8 //! - The explanation is expected to contain a `doctest` that fails with the correct error code. (`EXEMPT_FROM_DOCTEST` *currently* bypasses this check)
9 //! - Note that other stylistic conventions for markdown files are checked in the `style.rs` tidy check.
11 //! 3. We check that the error code has a UI test in `tests/ui/error-codes/`.
12 //! - We ensure that there is both a `Exxxx.rs` file and a corresponding `Exxxx.stderr` file.
13 //! - We also ensure that the error code is used in the tests.
14 //! - *Currently*, it is possible to opt-out of this check with the `EXEMPTED_FROM_TEST` constant.
16 //! 4. We check that the error code is actually emitted by the compiler.
17 //! - This is done by searching `compiler/` with a regex.
19 use std::{ffi::OsStr, fs, path::Path};
23 use crate::walk::{filter_dirs, walk, walk_many};
25 const ERROR_CODES_PATH: &str = "compiler/rustc_error_codes/src/error_codes.rs";
26 const ERROR_DOCS_PATH: &str = "compiler/rustc_error_codes/src/error_codes/";
27 const ERROR_TESTS_PATH: &str = "tests/ui/error-codes/";
29 // Error codes that (for some reason) can't have a doctest in their explanation. Error codes are still expected to provide a code example, even if untested.
30 const IGNORE_DOCTEST_CHECK: &[&str] = &["E0464", "E0570", "E0601", "E0602", "E0640", "E0717"];
32 // Error codes that don't yet have a UI test. This list will eventually be removed.
33 const IGNORE_UI_TEST_CHECK: &[&str] =
34 &["E0461", "E0465", "E0476", "E0514", "E0523", "E0554", "E0640", "E0717", "E0729"];
36 macro_rules! verbose_print {
37 ($verbose:expr, $($fmt:tt)*) => {
39 println!("{}", format_args!($($fmt)*));
44 pub fn check(root_path: &Path, search_paths: &[&Path], verbose: bool, bad: &mut bool) {
45 let mut errors = Vec::new();
47 // Stage 1: create list
48 let error_codes = extract_error_codes(root_path, &mut errors, verbose);
49 println!("Found {} error codes", error_codes.len());
50 println!("Highest error code: `{}`", error_codes.iter().max().unwrap());
52 // Stage 2: check list has docs
53 let no_longer_emitted = check_error_codes_docs(root_path, &error_codes, &mut errors, verbose);
55 // Stage 3: check list has UI tests
56 check_error_codes_tests(root_path, &error_codes, &mut errors, verbose, &no_longer_emitted);
58 // Stage 4: check list is emitted by compiler
59 check_error_codes_used(search_paths, &error_codes, &mut errors, &no_longer_emitted, verbose);
63 tidy_error!(bad, "{}", error);
67 /// Stage 1: Parses a list of error codes from `error_codes.rs`.
68 fn extract_error_codes(root_path: &Path, errors: &mut Vec<String>, verbose: bool) -> Vec<String> {
69 let path = root_path.join(Path::new(ERROR_CODES_PATH));
71 fs::read_to_string(&path).unwrap_or_else(|e| panic!("failed to read `{path:?}`: {e}"));
73 let mut error_codes = Vec::new();
74 let mut reached_undocumented_codes = false;
76 for line in file.lines() {
77 let line = line.trim();
79 if !reached_undocumented_codes && line.starts_with('E') {
80 let split_line = line.split_once(':');
82 // Extract the error code from the line, emitting a fatal error if it is not in a correct format.
83 let err_code = if let Some(err_code) = split_line {
87 "Expected a line with the format `Exxxx: include_str!(\"..\")`, but got \"{}\" \
88 without a `:` delimiter",
94 // If this is a duplicate of another error code, emit a fatal error.
95 if error_codes.contains(&err_code) {
96 errors.push(format!("Found duplicate error code: `{}`", err_code));
100 // Ensure that the line references the correct markdown file.
101 let expected_filename = format!(" include_str!(\"./error_codes/{}.md\"),", err_code);
102 if expected_filename != split_line.unwrap().1 {
104 "Error code `{}` expected to reference docs with `{}` but instead found `{}` in \
105 `compiler/rustc_error_codes/src/error_codes.rs`",
108 split_line.unwrap().1,
113 error_codes.push(err_code);
114 } else if reached_undocumented_codes && line.starts_with('E') {
115 let err_code = match line.split_once(',') {
117 Some((err_code, _)) => err_code,
121 verbose_print!(verbose, "warning: Error code `{}` is undocumented.", err_code);
123 if error_codes.contains(&err_code) {
124 errors.push(format!("Found duplicate error code: `{}`", err_code));
127 error_codes.push(err_code);
128 } else if line == ";" {
129 // Once we reach the undocumented error codes, adapt to different syntax.
130 reached_undocumented_codes = true;
137 /// Stage 2: Checks that long-form error code explanations exist and have doctests.
138 fn check_error_codes_docs(
140 error_codes: &[String],
141 errors: &mut Vec<String>,
144 let docs_path = root_path.join(Path::new(ERROR_DOCS_PATH));
146 let mut no_longer_emitted_codes = Vec::new();
148 walk(&docs_path, &mut |_| false, &mut |entry, contents| {
149 let path = entry.path();
151 // Error if the file isn't markdown.
152 if path.extension() != Some(OsStr::new("md")) {
154 "Found unexpected non-markdown file in error code docs directory: {}",
160 // Make sure that the file is referenced in `error_codes.rs`
161 let filename = path.file_name().unwrap().to_str().unwrap().split_once('.');
162 let err_code = filename.unwrap().0; // `unwrap` is ok because we know the filename is in the correct format.
164 if error_codes.iter().all(|e| e != err_code) {
166 "Found valid file `{}` in error code docs directory without corresponding \
167 entry in `error_code.rs`",
173 let (found_code_example, found_proper_doctest, emit_ignore_warning, no_longer_emitted) =
174 check_explanation_has_doctest(&contents, &err_code);
176 if emit_ignore_warning {
179 "warning: Error code `{err_code}` uses the ignore header. This should not be used, add the error code to the \
180 `IGNORE_DOCTEST_CHECK` constant instead."
184 if no_longer_emitted {
185 no_longer_emitted_codes.push(err_code.to_owned());
188 if !found_code_example {
191 "warning: Error code `{err_code}` doesn't have a code example, all error codes are expected to have one \
197 let test_ignored = IGNORE_DOCTEST_CHECK.contains(&&err_code);
199 // Check that the explanation has a doctest, and if it shouldn't, that it doesn't
200 if !found_proper_doctest && !test_ignored {
202 "`{}` doesn't use its own error code in compile_fail example",
205 } else if found_proper_doctest && test_ignored {
207 "`{}` has a compile_fail doctest with its own error code, it shouldn't \
208 be listed in `IGNORE_DOCTEST_CHECK`",
214 no_longer_emitted_codes
217 /// This function returns a tuple indicating whether the provided explanation:
218 /// a) has a code example, tested or not.
219 /// b) has a valid doctest
220 fn check_explanation_has_doctest(explanation: &str, err_code: &str) -> (bool, bool, bool, bool) {
221 let mut found_code_example = false;
222 let mut found_proper_doctest = false;
224 let mut emit_ignore_warning = false;
225 let mut no_longer_emitted = false;
227 for line in explanation.lines() {
228 let line = line.trim();
230 if line.starts_with("```") {
231 found_code_example = true;
233 // Check for the `rustdoc` doctest headers.
234 if line.contains("compile_fail") && line.contains(err_code) {
235 found_proper_doctest = true;
238 if line.contains("ignore") {
239 emit_ignore_warning = true;
240 found_proper_doctest = true;
243 .starts_with("#### Note: this error code is no longer emitted by the compiler")
245 no_longer_emitted = true;
246 found_code_example = true;
247 found_proper_doctest = true;
251 (found_code_example, found_proper_doctest, emit_ignore_warning, no_longer_emitted)
254 // Stage 3: Checks that each error code has a UI test in the correct directory
255 fn check_error_codes_tests(
257 error_codes: &[String],
258 errors: &mut Vec<String>,
260 no_longer_emitted: &[String],
262 let tests_path = root_path.join(Path::new(ERROR_TESTS_PATH));
264 for code in error_codes {
265 let test_path = tests_path.join(format!("{}.stderr", code));
267 if !test_path.exists() && !IGNORE_UI_TEST_CHECK.contains(&code.as_str()) {
270 "warning: Error code `{code}` needs to have at least one UI test in the `tests/error-codes/` directory`!"
274 if IGNORE_UI_TEST_CHECK.contains(&code.as_str()) {
275 if test_path.exists() {
277 "Error code `{code}` has a UI test in `tests/ui/error-codes/{code}.rs`, it shouldn't be listed in `EXEMPTED_FROM_TEST`!"
283 let file = match fs::read_to_string(&test_path) {
288 "warning: Failed to read UI test file (`{}`) for `{code}` but the file exists. The test is assumed to work:\n{err}",
295 if no_longer_emitted.contains(code) {
296 // UI tests *can't* contain error codes that are no longer emitted.
300 let mut found_code = false;
302 for line in file.lines() {
304 // Assuming the line starts with `error[E`, we can substring the error code out.
305 if s.starts_with("error[E") {
306 if &s[6..11] == code {
316 "warning: Error code {code}`` has a UI test file, but doesn't contain its own error code!"
322 /// Stage 4: Search `compiler/` and ensure that every error code is actually used by the compiler and that no undocumented error codes exist.
323 fn check_error_codes_used(
324 search_paths: &[&Path],
325 error_codes: &[String],
326 errors: &mut Vec<String>,
327 no_longer_emitted: &[String],
330 // We want error codes which match the following cases:
332 // * foo(a, E0111, a)
335 // * #[error = "E0111"]
336 let regex = Regex::new(r#"[(,"\s](E\d{4})[,)"]"#).unwrap();
338 let mut found_codes = Vec::new();
340 walk_many(search_paths, &mut filter_dirs, &mut |entry, contents| {
341 let path = entry.path();
343 // Return early if we aren't looking at a source file.
344 if path.extension() != Some(OsStr::new("rs")) {
348 for line in contents.lines() {
349 // We want to avoid parsing error codes in comments.
350 if line.trim_start().starts_with("//") {
354 for cap in regex.captures_iter(line) {
355 if let Some(error_code) = cap.get(1) {
356 let error_code = error_code.as_str().to_owned();
358 if !error_codes.contains(&error_code) {
359 // This error code isn't properly defined, we must error.
360 errors.push(format!("Error code `{}` is used in the compiler but not defined and documented in `compiler/rustc_error_codes/src/error_codes.rs`.", error_code));
364 // This error code can now be marked as used.
365 found_codes.push(error_code);
371 for code in error_codes {
372 if !found_codes.contains(code) && !no_longer_emitted.contains(code) {
373 errors.push(format!("Error code `{code}` exists, but is not emitted by the compiler!"))
376 if found_codes.contains(code) && no_longer_emitted.contains(code) {
379 "warning: Error code `{code}` is used when it's marked as \"no longer emitted\""