go/goals/test 'types.UnionType' object is not iterable in debug log

[sureshjoshi]

Found this in the debug logs, never seen it before - doesn't seem to error or visibly warn.

pants/src/python/pants/backend/go/goals/test.py:333

Rule visitor failed to inspect assignment expression for ['_exit_code', '_stderr'] - tuple[int, str] | None:

'types.UnionType' object is not iterable

[jsirois]

FWIW, science has to deal with this. It has an ~auto doc generation system that walks dataclasses and needs to deal with union types. Maybe useful reading:
https://github.com/a-scie/lift/blob/d71adfeaa9e7bf7561c3bcb1e8af8079e75c1325/science/types.py#L96-L102