ruff/crates/ruff_python_semantic/src
Brent Westbrook 2baaedda6c
[syntax-errors] Start detecting compile-time syntax errors (#16106)
## Summary

This PR implements the "greeter" approach for checking the AST for
syntax errors emitted by the CPython compiler. It introduces two main
infrastructural changes to support all of the compile-time errors:
1. Adds a new `semantic_errors` module to the parser crate with public
`SemanticSyntaxChecker` and `SemanticSyntaxError` types
2. Embeds a `SemanticSyntaxChecker` in the `ruff_linter::Checker` for
checking these errors in ruff

As a proof of concept, it also implements detection of two syntax
errors:
1. A reimplementation of
[`late-future-import`](https://docs.astral.sh/ruff/rules/late-future-import/)
(`F404`)
2. Detection of rebound comprehension iteration variables
(https://github.com/astral-sh/ruff/issues/14395)

## Test plan
Existing F404 tests, new inline tests in the `ruff_python_parser` crate,
and a linter CLI test showing an example of the `Message` output.

I also tested in VS Code, where `preview = false` and turning off syntax
errors both disable the new errors:


![image](https://github.com/user-attachments/assets/cf453d95-04f7-484b-8440-cb812f29d45e)

And on the playground, where `preview = false` also disables the errors:


![image](https://github.com/user-attachments/assets/a97570c4-1efa-439f-9d99-a54487dd6064)


Fixes #14395

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
2025-03-21 14:45:25 -04:00
..
analyze Consider all TYPE_CHECKING symbols for type-checking blocks (#16669) 2025-03-13 15:37:37 +01:00
model Upgrade Rust toolchain to 1.83 (#14677) 2024-11-29 12:05:05 +00:00
binding.rs [ruff] Fix false positive on global keyword (RUF052) (#15235) 2025-01-14 08:36:40 +01:00
branches.rs Add branch detection to the semantic model (#6694) 2023-08-19 21:28:17 +00:00
context.rs Remove separate ReferenceContext enum (#4631) 2023-05-24 15:12:38 +00:00
definition.rs Make setting and retrieving pydocstyle settings less tedious (#12582) 2024-07-31 10:39:33 +01:00
globals.rs Refine SemanticModel lifetime bounds (#10221) 2024-03-04 09:21:13 +01:00
imports.rs Config error only when flake8-import-conventions alias conflicts with isort.required-imports bound name (#15918) 2025-02-04 17:05:35 -06:00
lib.rs Move required import parsing out of lint rule (#12536) 2024-07-26 13:35:45 -04:00
model.rs [syntax-errors] Start detecting compile-time syntax errors (#16106) 2025-03-21 14:45:25 -04:00
nodes.rs Remove customizable reference enum names (#15647) 2025-01-21 13:46:31 -05:00
reference.rs [ruff] Avoid emitting assignment-in-assert when all references to the assigned variable are themselves inside asserts (RUF018) (#14661) 2024-11-29 13:36:59 +00:00
scope.rs Upgrade Rust toolchain to 1.83 (#14677) 2024-11-29 12:05:05 +00:00
star_import.rs Make ImportFrom level just a u32 (#11170) 2024-04-26 20:38:35 -06:00