[pyflakes] Treat function-scope bare annotations as locals per PEP 526 (F821) #21540
Conversation
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| code | total | + violation | - violation | + fix | - fix |
|---|---|---|---|---|---|
| RUF100 | 1 | 1 | 0 | 0 | 0 |
Linter (preview)
ℹ️ ecosystem check detected linter changes. (+1 -0 violations, +0 -0 fixes in 1 projects; 54 projects unchanged)
apache/airflow (+1 -0 violations, +0 -0 fixes)
ruff check --no-cache --exit-zero --no-fix --output-format concise --preview --select ALL
+ task-sdk/src/airflow/sdk/execution_time/callback_runner.py:109:28: RUF100 [*] Unused `noqa` directive (unused: `F821`)
Changes by rule (1 rules affected)
| code | total | + violation | - violation | + fix | - fix |
|---|---|---|---|---|---|
| RUF100 | 1 | 1 | 0 | 0 | 0 |
| def demonstrate_bare_local_annotation(): | ||
| x: int | ||
| print(x) |
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I still haven't looked too closely at this, but I agree that it's unfortunate not to flag this case. It might be worth looking into how ty handles this since it seems to get the expected result in both cases:
https://play.ty.dev/c6f45910-a2bd-4745-827b-f29a148f4e63
It doesn't seem to be related to nonlocal, though, because commenting it out doesn't change ty's diagnostics.
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One option to do this is then something like
BindingKind::Annotation if !self.in_stub_file() => {
if self.scopes[self.bindings[binding_id].scope]
.kind
.is_function()
{
// If we're in a function scope, and the annotation is local to that scope,
// treat it as unbound (since it's not assigned).
// If it's an enclosing scope, we treat it as resolved (to support closures).
if index == 0 {
self.unresolved_references.push(
name.range,
self.exceptions(),
UnresolvedReferenceFlags::empty(),
);
return ReadResult::UnboundLocal(binding_id);
}
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
continue;
}
if we do this then both the cases will be handled i.e. error in this case
def demonstrate_bare_local_annotation():
x: int
print(x)
and no error in the closure cases i.e. the setter,getter example
but then again we will have edge cases like these where no error will be reported [although even ty doesn't report them]
def demo_closure():
x: int
def func():
return x
What do you think about this
2 participants
Summary
Resolves #21494
Treat function-scope annotated variables as locals per PEP 526 , preventing F821 false positives.
Test Plan
Added tests for these cases in
crates/ruff_linter/resources/test/fixtures/pyflakes/F821_34.py