ruff/crates/ty_python_semantic
David Peter 04457f99b6
[ty] Protocols: Fixpoint iteration for fully-static check (#17880)
## Summary

A recursive protocol like the following would previously lead to stack
overflows when attempting to create the union type for the `P | None`
member, because `UnionBuilder` checks if element types are fully static,
and the fully-static check on `P` would in turn list all members and
check whether all of them were fully static, leading to a cycle.

```py
from __future__ import annotations

from typing import Protocol

class P(Protocol):
    parent: P | None
```

Here, we make the fully-static check on protocols a salsa query and add
fixpoint iteration, starting with `true` as the initial value (assume
that the recursive protocol is fully-static). If the recursive protocol
has any non-fully-static members, we still return `false` when
re-executing the query (see newly added tests).

closes #17861

## Test Plan

Added regression test
2025-05-07 08:55:21 +02:00
..
resources [ty] Protocols: Fixpoint iteration for fully-static check (#17880) 2025-05-07 08:55:21 +02:00
src [ty] Protocols: Fixpoint iteration for fully-static check (#17880) 2025-05-07 08:55:21 +02:00
tests Use #[expect(lint)] over #[allow(lint)] where possible (#17822) 2025-05-03 21:20:31 +02:00
build.rs Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
Cargo.toml Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
mdtest.py Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
mdtest.py.lock Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00