Required/NotRequired don't work with __future__.annotations

[jcrist]

Required/NotRequired aren't properly detected when from __future__ import annotations is used, leading to incorrect __required_keys__/__optional_keys__ sets.

Reproduced with 4.3.0.

from __future__ import annotations  # comment this line out and things work correctly
from typing_extensions import NotRequired, TypedDict

class Test(TypedDict):
    a: int
    b: NotRequired[int]

assert Test.__required_keys__ == {"a"}
assert Test.__optional_keys__ == {"b"}

$ python test.py
Traceback (most recent call last):
  File "/home/jcristharif/Code/test.py", line 8, in <module>
    assert Test.__required_keys__ == {"a"}
AssertionError

[JelleZijlstra]

What Python version are you running? Does this reproduce with typing too on Python 3.11?

[jcrist]

I don't have (easy) access to a 3.11 build, but it reproduces with 4.3.0 on both 3.10 and 3.9.

[AlexWaygood]

I can reproduce using typing.TypedDict and typing.NotRequired on the CPython main branch (3.12), so I assume it reproduces on 3.11 using the stdlib typing module as well.

[yixun-alpha]

just ran into this issue with 4.3.0 and python 3.7.6 - any fix in the works? thanks!

[gvanrossum]

So is this fixed by #60 or not? It seems to be an issue with the upstream cpython typing module as well -- did someone already file an issue there? Please link it here.

[JelleZijlstra]

#60 would fix this in simple cases, but I think it will cause more problems than it solves. I'm inclined to wontfix this. Maybe we can revisit once there's a resolution on the PEP 563/649 saga.

[gvanrossum]

It's fine to not want to solve this for now. In fact one could argue that, since the point of from __future__ import annotations is not to incur runtime costs, you get what you ask for. (Not sure if that's totally fair, but it's a possible POV.)