mock.patch.multiple(..., **patches) type checks against non-**kwargs arguments

[asottile]

example:

import os
from unittest import mock


patches = {'listdir': lambda x: ['t']}
with mock.patch.multiple(os, **patches):
    pass

output:

$ mypy --version
mypy 0.770
$ mypy t.py
t.py:6: error: Argument 2 to "multiple" of "_patcher" has incompatible type "**Dict[str, Callable[[Any], List[str]]]"; expected "bool"
Found 1 error in 1 file (checked 1 source file)

expected: no errors -- the stub for multiple takes **kwargs: Any: https://github.com/python/typeshed/blob/508fd844992f5ba8398fec5defa5bb7a44c71269/stdlib/3/unittest/mock.pyi#L91

[msullivan]

I think this is intended behavior but also it is unfortunate and frustrating in this case.

It is erroring because patches could contain values for the actual keyword arguments of mock.patch.multiple itself. Really it is kind of an API mistake for mock.patch.multiple to take a kwargs and also a bunch of keywords arguments...