Suppose I del a variable in an Exception branch:

def my_fn(a: str) -> str:
    try:
        print(a)
    except Exception:
        del a
        raise
    else:
        return a

a must always exist in the else branch, but Ruff claims it's undefined:

~$ ruff foobar.py --isolated
foobar.py:8:16: F821 Undefined name `a`
Found 1 error.

(line 8 char 16 is the location of the a in the return statement)

This is on version 0.0.281:

~$ ruff --version
ruff 0.0.281