ruff/crates/ruff_python_parser
Bhuminjay Soni c722f498fe
[`flake8-bugbear`] Catch `yield` expressions within other statements (`B901`) (#21200)
## Summary

This PR re-implements [return-in-generator
(B901)](https://docs.astral.sh/ruff/rules/return-in-generator/#return-in-generator-b901)
for async generators as a semantic syntax error. This is not a syntax
error for sync generators, so we'll need to preserve both the lint rule
and the syntax error in this case.

It also updates B901 and the new implementation to catch cases where the
generator's `yield` or `yield from` expression is part of another
statement, as in:

```py
def foo():
    return (yield)
```

These were previously not caught because we only looked for
`Stmt::Expr(Expr::Yield)` in `visit_stmt` instead of visiting `yield`
expressions directly. I think this modification is within the spirit of
the rule and safe to try out since the rule is in preview.

## Test Plan

<!-- How was it tested? -->
I have written tests as directed in #17412

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Signed-off-by: 11happy <bhuminjaysoni@gmail.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
2025-12-03 12:05:15 -05:00
..
resources [syntax-error] Default type parameter followed by non-default type parameter (#21657) 2025-12-03 12:01:31 +05:30
src [`flake8-bugbear`] Catch `yield` expressions within other statements (`B901`) (#21200) 2025-12-03 12:05:15 -05:00
tests [syntax-error] Default type parameter followed by non-default type parameter (#21657) 2025-12-03 12:01:31 +05:30
CONTRIBUTING.md Update usage instructions and lockfile for py-fuzzer script (#20940) 2025-10-17 15:57:17 +01:00
Cargo.toml [ty] Add environment variable to dump Salsa memory usage stats (#18928) 2025-06-26 21:27:51 +00:00
README.md Add basic docs for the parser crate (#11199) 2024-04-29 17:08:07 +00:00

README.md

Ruff Python Parser

Ruff's Python parser is a hand-written recursive descent parser which can parse Python source code into an Abstract Syntax Tree (AST). It also utilizes the Pratt parsing technique to parse expressions with different precedence.

Try out the parser in the playground.

Python version support

The parser supports the latest Python syntax, which is currently Python 3.12. It does not throw syntax errors if it encounters a syntax feature that is not supported by the target-version. This will be fixed in a future release (see https://github.com/astral-sh/ruff/issues/6591).

Contributing

Refer to the contributing guidelines to get started and GitHub issues with the parser label for issues that need help.