ruff/crates/ruff_python_parser
Brent Westbrook ab1011ce70
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[syntax-errors] Single starred assignment target (#17024)
Summary
--

Detects starred assignment targets outside of tuples and lists like `*a
= (1,)`.

This PR only considers assignment statements. I also checked annotated
assigment statements, but these give a separate error that we already
catch, so I think they're okay not to consider:

```pycon
>>> *a: list[int] = []
  File "<python-input-72>", line 1
    *a: list[int] = []
      ^
SyntaxError: invalid syntax
```

Fixes #13759

Test Plan
--

New inline tests, plus a new `SemanticSyntaxError` for an existing
parser test. I also removed a now-invalid case from an otherwise-valid
test fixture.

The new semantic error leads to two errors for the case below:

```python
*foo() = 42
```

but this matches [pyright] too.

[pyright]: https://pyright-play.net/?code=FQMw9mAUCUAEC8sAsAmAUEA
2025-03-29 12:35:47 -04:00
..
resources [syntax-errors] Single starred assignment target (#17024) 2025-03-29 12:35:47 -04:00
src [syntax-errors] Single starred assignment target (#17024) 2025-03-29 12:35:47 -04:00
tests [syntax-errors] Single starred assignment target (#17024) 2025-03-29 12:35:47 -04:00
Cargo.toml Allow passing ParseOptions to inline tests (#16357) 2025-02-27 10:23:15 -05:00
CONTRIBUTING.md py-fuzzer: recommend using uvx rather than uv run to run the fuzzer (#14645) 2024-11-27 22:19:52 +00:00
README.md Add basic docs for the parser crate (#11199) 2024-04-29 17:08:07 +00:00

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.