[attr-defined] error on one-to-one relation

[yoanis-sl]

Bug report

What's wrong

I have the following models:

# Content from video.models

class BackingVideo(AudioMixin):
    asset = models.OneToOneField(
        "video.Asset", on_delete=models.SET_NULL, null=True, blank=True, related_name="backing_video"
    )
class Asset(BaseModelMixin):
    mux_asset_id = models.CharField(max_length=512, blank=False)

and when I run mypy on the code base I get this error:

video/management/commands/copy_mux_assets.py:126: error: "Asset" has no attribute "backing_video"  [attr-defined]
Found 1 error in 1 file (checked 75 source files)

Which seems a bit strange as I seem to have all of the proper setup.

This is what the relevant pyproject.toml file looks like:

[tool.mypy]
explicit_package_bases = true
plugins = ["mypy_django_plugin.main", "mypy_drf_plugin.main"]
ignore_missing_imports = false
disallow_untyped_calls = true
disallow_untyped_defs = true
disallow_incomplete_defs = true
check_untyped_defs = true

[tool.django-stubs]
django_settings_module = "config.settings"

Any thoughts on what I might be doing wrong here?

Any help is appreciated. Thx!

System information

• OS:
• python version: 3.13
• django version: 5.1.7
• mypy version: 1.15.0
• django-stubs version: 5.1.3
• django-stubs-ext version: 5.1.3

[sobolevn]

Sorry, what is MuxAsset? I only see Asset in code.

[yoanis-sl]

Sorry, what is MuxAsset? I only see Asset in code.

It's Asset. MuxAsset was just some cleaning left-over before posting here to make the issue more concise.

[sobolevn]

If you can write a test case with a repro - we can probably fix this, right now - I can't reproduce this problem :(