mirror of https://github.com/astral-sh/ruff
8727a7b179
## Summary This fixes https://github.com/astral-sh/ty/issues/1736 where recursive generic protocols with growing specializations caused a stack overflow. The issue occurred with protocols like: ```python class C[T](Protocol): a: 'C[set[T]]' ``` When checking `C[set[int]]` against e.g. `C[Unknown]`, member `a` requires checking `C[set[set[int]]]`, which requires `C[set[set[set[int]]]]`, etc. Each level has different type specializations, so the existing cycle detection (using full types as cache keys) didn't catch the infinite recursion. This fix adds a simple recursion depth limit (64) to the CycleDetector. When the depth exceeds the limit, we return the fallback value (assume compatible) to safely terminate the recursion. This is a bit of a blunt hammer, but it should be broadly effective to prevent stack overflow in any nested-relation case, and it's hard to imagine that non-recursive nested relation comparisons of depth > 64 exist much in the wild. ## Test Plan Added mdtest. |
||
|---|---|---|
| .. | ||
| resources | ||
| src | ||
| tests | ||
| Cargo.toml | ||
| build.rs | ||
| mdtest.py | ||
| mdtest.py.lock | ||