ruff/crates/red_knot_python_semantic
David Peter 4d50ee6f52
[red-knot] Track reachability of scopes (#17332)
## Summary

Track the reachability of nested scopes within their parent scopes. We
use this as an additional requirement for emitting
`unresolved-reference` diagnostics (and in the future,
`unresolved-attribute` and `unresolved-import`). This means that we only
emit `unresolved-reference` for a given use of a symbol if the use
itself is reachable (within its own scope), *and if the scope itself is
reachable*. For example, no diagnostic should be emitted for the use of
`x` here:

```py
if False:
    x = 1

    def f():
        print(x)  # this use of `x` is reachable inside the `f` scope,
                  # but the whole `f` scope is not reachable.
```

There are probably more fine-grained ways of solving this problem, but
they require a more sophisticated understanding of nested scopes (see
#15777, in particular
https://github.com/astral-sh/ruff/issues/15777#issuecomment-2788950267).
But it doesn't seem completely unreasonable to silence *this specific
kind of error* in unreachable scopes.

## Test Plan

Observed changes in reachability tests and ecosystem.
2025-04-10 11:56:40 +00:00
..
resources [red-knot] Track reachability of scopes (#17332) 2025-04-10 11:56:40 +00:00
src [red-knot] Track reachability of scopes (#17332) 2025-04-10 11:56:40 +00:00
tests [red-knot] Add GitHub PR annotations when mdtests fail in CI (#17150) 2025-04-02 21:51:52 +01:00
build.rs
Cargo.toml [red-knot] Add a test to ensure that KnownClass::try_from_file_and_name() is kept up to date (#16326) 2025-02-24 12:14:20 +00:00
mdtest.py mdtest.py: do a full mdtest run immediately when the script is executed (#17128) 2025-04-01 19:27:55 +01:00
mdtest.py.lock [red-knot] Markdown test runner (#15632) 2025-01-21 14:06:35 +01:00