NoneType' object is not iterable in resolve_fw_decl

[mitar]

>>> import typing
>>> from pytypes import type_util
>>> T = typing.TypeVar('T')
>>> class Foo(typing.Generic[T]):
...   pass
... 
>>> type_util.resolve_fw_decl(Foo)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not iterable

[Stewori]

When posting issue-related stacktraces would be helpful to set pytypes.clean_traceback = False (right after pytypes import) to make the pytypes-internal part of the stacktrace visible.

[mitar]

Oh, didn't know about that.

[mitar]

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../pytypes/type_util.py", line 905, in resolve_fw_decl
    for in_tp in in_type.__args__])
TypeError: 'NoneType' object is not iterable

[mitar]

So __args__ is None in this case.

[Stewori]

Alright.
Changing line 903 from
elif hasattr(in_type, '__args__'):
to
elif hasattr(in_type, '__args__') and in_type.__args is not None:
would solve this issue I suppose.
I don't have time to work on pytyes right now, so it would be great if you could test this solution (and ideally push)...

[mitar]

I will look into this. The #35 is in fact more problematic to me, it seems I have found also other examples where it does not work. :-(

[mitar]

Done: #37.

[Stewori]

Thanks!