Undefined name error when using late wildcard imports

[IwoHerka]

Hello,

I've encountered a bug (or I think so) when using late wildcard imports. It can be reproduced as follows:

file1.py

def foo() -> int:
    return bar()

from file2 import *
assert foo() == 1

file2.py

def bar() -> int:
    return 1

This yields:

file1.py:2: error: Name 'bar' is not defined

Version with

from file2 import bar

works fine (i.e. no errors are thrown).

This version works too:

from file2 import *

def foo() -> int:
    return bar()

assert foo() == 1

I'm using version 0.641 installed from PyPI. I encounter the same behaviour when installed from Git master (as of 2680c3).

I'm not using any options (just mypy file1.py).

Python version is 3.6.6.

[ilevkivskyi]

We are planning a major redesign of our semantic analyzer in next months that will likely solve this kind of issues. For now you can use the workarounds you found.

[JukkaL]

The underlying problem is that mypy currently doesn't support forward references to a star import. from x import * is processed at a later stage of analysis than other imports, which breaks forward references. Forward references to imported names in general are problematic at the moment though; #4687 is a related issue.

[arquolo]

Another bug with wildcard imports (typical code from asyncio.__init__):

from .submodule import *
__all__ = submodule.__all__

This yields:
file.py:2: error: Name `submodule` is not defined
Using mypy 0.750 from pip.

[msullivan]

Looks like this was fixed by the new semantic analyzer