__getattr__ support for metaclass

[yuyangguo42]

from six import add_metaclass

class MetaFoo(type):
    SOME_DICT = {
        'asdf': 'bbbb',
    }
    def __getattr__(cls, attr):
        # type: (str) -> str
        return MetaFoo.SOME_DICT[attr]

@add_metaclass(MetaFoo)
class Foo(object):
    pass

print(Foo.asdf)  # error: Type[Foo] has no attribute "asdf"

So not sure if this is supposed to be supported or the usage pattern should be dis-encouraged anyways ><

[ilevkivskyi]

This is not very high priority, but on the other hand this should be easy to implement. If you want to make a PR, then please take a look at checkmember.analyze_class_attribute_access (you can see how to make special treatment of __getattr__ etc. in checkmember.analyze_member_var_access)

[elazarg]

It's unrelated to member access in metaclasses. mypy simply does not understand add_metaclass. It works fine with standard metaclasses, and on the other hand

x = Foo  # type: MetaFoo

fails too.

[elazarg]

So this is duplicate of #3365.

[ilevkivskyi]

OK, then I am closing this as a duplicate.

[elazarg]

@yuyangguo42 you may want to try #3842.