false positive for RET504 in case of globals

[tlambert03]

The following code results in RET504 Unnecessary variable assignment before return statement

X: int | None = None

def get_x() -> int:
    global X
    if X is None:
        X = 1
    return X

however, as it's modifying a global, it's not unnecessary assignment. (naturally, whether this is a good pattern is a separate discussion 😂 ... but it's not syntactically unnecessary).

(Haven't checked the behavior of flake8-return)

[charliermarsh]

Hah! Yeah, globals should probably be omitted from this check, since assignments are themselves side-effects.

[tlambert03]

Thank you! 🙏

[charliermarsh]

All @squiddy :)