Possible error in PLE0605

[nstarman]

In astropy/astropy#15385 we are trying to fix some __all__ statements and ran into the following

__all__ = [...]
logging_levels = ["NOTSET", ...]
...
__all__ += logging_levels

My suggested fix was

__all__ = [...]
__all__ += (logging_levels := ["NOTSET", ...])

However PLE0605 is still complaining. I don't think this is correct since the above should be, from the "perspective" of __all__ equivalent to

__all__ = [...]
__all__ += ["NOTSET", ...]

which passes the check.

The inclusion of the walrus operator for assigning to another variable makes the AST more complicated but should be equivalent statically to excluding the walrus.

[zanieb]

Thanks for the report!

Hm... in the example:

from other import a, b

__all__ = ["a"]
__all__ += (foo := ["b"])

pyright reports the symbol b as unused and displays the warning Operation on "__all__" is not supported, so exported symbol list may be incorrect (reportUnsupportedDunderAll).

Although I agree this is syntactically equivalent, if it's not supported by type checkers I'm not sure we should treat it as valid.

[charliermarsh]

I think it's reasonable to support if the code changes aren't too tricky :)