`ContentType.app_label` is typed as `Any` by mypy

[mthuurne]

Bug report

What's wrong

If I run mypy on this code:

from django.contrib.contenttypes.models import ContentType
from django.db import models

def f(model: type[models.Model]) -> None:
    ct = ContentType.objects.get_for_model(model)
    reveal_type(ct)
    reveal_type(ct.app_label)

It outputs:

testcase.py:6: note: Revealed type is "django.contrib.contenttypes.models.ContentType"
testcase.py:7: note: Revealed type is "Any"

In django-stubs/contrib/contenttypes/models.pyi, the ContentType class is annotated as follows:

class ContentType(models.Model):
    id: int
    app_label: models.CharField
    # (snip)

So the type for ct is inferred as expected, but for the app_label field it is not, even though that field is annotated in the stubs. Is this some bug or limitation of the plugin?

How is that should be

The runtime type for ct.app_label is str, so ideally that would be the inferred type.

System information

• OS:
• python version: 3.10.12
• django version: 4.2
• mypy version: 1.13.0
• django-stubs version: 5.1.1
• django-stubs-ext version: 5.1.1

[sobolevn]

PR is welcome

[mthuurne]

I could use some hints on where to start looking. Is it expected or unexpected that the type for app_label isn't inferred? And would the solution indeed be to change the plugin?