GenericAPIView has missing type parameters, but when added 'type' object is not subscriptable

[XF-FW]

Bug report

What's wrong

When using mypy with strict=true, it issues the following error:
Missing type parameters for generic type "GenericAPIView".

So, I check the type and add it, but I'm now getting a runtime error:
TypeError: 'type' object is not subscriptable.

I am using django_stubs_ext.monkeypatch(), which solves the problem for other similar issues.

I haven't test it on its own, but this should suffice, as a reproducible test:

from rest_framework.generics import GenericAPIView

class ShouldWorkView(GenericAPIView[None]):
   ...

How is that should be

The above example should pass, with no issues.

System information

• OS: Arch
• python version: 3.10
• django version: 4.0.7
• mypy version: 0.942
• django-stubs version: 1.12.0

[ewiner]

I believe you're hitting this issue: https://mypy.readthedocs.io/en/latest/runtime_troubles.html#using-classes-that-are-generic-in-stubs-but-not-at-runtime. The solution suggested on that doc page worked for me.

[XF-FW]

Yep, that worked. Thanks!

It still feels like a workaround, so I'll leave this open. If the maintainers feel like this should be the default behavior, feel free to close it.

[XF-FW]

The same thing happens when trying to subclass PrimaryKeyRelatedField.

Edit: And Field.

[monosans]

You can pass the classes you want to monkeypatch in the extra_classes parameter to django_stubs_ext.monkeypatch().

Example:

import django_stubs_ext
from rest_framework import fields, generics

django_stubs_ext.monkeypatch(
    extra_classes=(fields.Field, generics.GenericAPIView)
)

or you can manually monkeypatch them:

from rest_framework import fields, generics

for cls in (fields.Field, generics.GenericAPIView):
    cls.__class_getitem__ = classmethod(  # type: ignore[attr-defined]
        lambda cls, *args, **kwargs: cls
    )

[XF-FW]

Thank you! That works perfectly.