rustpython_ruff_python_trivia/
pragmas.rs

1/// Returns `true` if a comment appears to be a pragma comment.
2///
3/// ```
4/// assert!(ruff_python_trivia::is_pragma_comment("# type: ignore"));
5/// assert!(ruff_python_trivia::is_pragma_comment("# noqa: F401"));
6/// assert!(ruff_python_trivia::is_pragma_comment("# noqa"));
7/// assert!(ruff_python_trivia::is_pragma_comment("# NoQA"));
8/// assert!(ruff_python_trivia::is_pragma_comment("# nosec"));
9/// assert!(ruff_python_trivia::is_pragma_comment("# nosec B602, B607"));
10/// assert!(ruff_python_trivia::is_pragma_comment("# isort: off"));
11/// assert!(ruff_python_trivia::is_pragma_comment("# isort: skip"));
12/// assert!(ruff_python_trivia::is_pragma_comment("# pyrefly: ignore[missing-attribute]"));
13/// ```
14pub fn is_pragma_comment(comment: &str) -> bool {
15    let Some(content) = comment.strip_prefix('#') else {
16        return false;
17    };
18    let trimmed = content.trim_start();
19
20    // Case-insensitive match against `noqa` (which doesn't require a trailing colon).
21    matches!(
22        trimmed.as_bytes(),
23        [b'n' | b'N', b'o' | b'O', b'q' | b'Q', b'a' | b'A', ..]
24    ) ||
25        // Case-insensitive match against pragmas that don't require a trailing colon.
26        trimmed.starts_with("nosec") ||
27        // Case-sensitive match against a variety of pragmas that _do_ require a trailing colon.
28        trimmed
29        .split_once(':')
30        .is_some_and(|(maybe_pragma, _)| matches!(maybe_pragma, "isort" | "type" | "pyright" | "pyrefly" | "pylint" | "flake8" | "ruff" | "ty"))
31}
32
33/// Returns the byte offset within `comment` where a trailing pragma comment starts,
34/// or `None` if no pragma is found.
35///
36/// For a plain pragma like `# noqa: F401`, returns `Some(0)`.
37/// For a nested pragma like `# some text # noqa: F401`, returns the offset of the
38/// trailing `#` that begins the pragma (i.e., the start of `# noqa: F401`).
39///
40/// ```
41/// assert_eq!(ruff_python_trivia::find_trailing_pragma_offset("# noqa: F401"), Some(0));
42/// assert_eq!(ruff_python_trivia::find_trailing_pragma_offset("# type: ignore"), Some(0));
43/// assert_eq!(ruff_python_trivia::find_trailing_pragma_offset("# some comment # noqa: F401"), Some(15));
44/// assert_eq!(ruff_python_trivia::find_trailing_pragma_offset("## noqa: F401"), Some(1));
45/// assert_eq!(ruff_python_trivia::find_trailing_pragma_offset("# just a comment"), None);
46/// ```
47pub fn find_trailing_pragma_offset(comment: &str) -> Option<usize> {
48    comment.match_indices('#').find_map(|(offset, _)| {
49        let sub_comment = &comment[offset..];
50        if is_pragma_comment(sub_comment) {
51            Some(offset)
52        } else {
53            None
54        }
55    })
56}
rustpython_ruff_python_trivia/pragmas.rs

rustpython_ruff_python_trivia/
pragmas.rs
