Cannot determine type Issue with near import loops

[timabbott]

I ran into this trying to get the sqlalchemy stubs working. The error is:

<string>:1: note: In module imported here:
typeshed/third_party/2.7/stest/__init__.pyi:4: error: Cannot determine type of 'Constraint'

Here's a reproducer zipped tar archive:
foo.zip

[JukkaL]

This is a known problem (though there doesn't seem to be an open issue). If there are cyclic module dependencies, type inference often needs help because mypy does only a single type checking pass.

In this particular case, you may want to rewrite cases like this:

Constraint = scheme.Constraint

into something like this:

from .scheme import Constraint as Constraint

Let me know if that works for you.

[timabbott]

That workaround worked for the sqlalchemy stubs; I had actually tried it before unsuccessfully, but I now suspect that was due to an unrelated problem.

[JukkaL]

Closing as this seems like a special case of #481.