Only populate a model argument for generic managers

[flaeppe]

I have made things!

Change the plugin so that non generic managers (like below) won't get an implicit model argument

class MyManager(models.Manager["MyModel"]):
    ...

class MyModel(models.Model):
    objects = MyManager()

Previously these(MyModel.objects) were assigned a type like: MyManager["MyModel"]

TODO:

• Ensure compatibility between a manager and the model it is assigned to. e.g. the model argument of a manager needs to be compatible with the model the manager is instantiated on
• Ensure compatibility between a manager and queryset e.g. the model argument of a manager needs to be compatible with the model argument of the queryset it's combined with

Related issues

• Refs: Declare manager class attributes on models as ClassVars #1672 (comment)
• Refs: Add TypeVar resolution for as_manager querysets (typeddjango#1646) #1666 (comment)

[sobolevn]

This is more correct! Thanks!

[sobolevn]

Maybe refactor into helper?

[flaeppe]

I think I found a mypy bug here, but I'm not sure. But the get_dynamic_class_hook isn't called for QuerySetGeneric["MyModel"].as_manager() due to ["MyModel"].

If I remove ["MyModel"] it is triggered. But that means the hook isn't compatible with a classmethod on a generic class.

I have no idea if it's unreasonable to expect it to be triggered, it just feels like a bug that adding type parameters affects the triggering..

[sobolevn]

Please, report it anyways :)

[sobolevn]

(and tag me, since I don't watch all issues)

[flaeppe]

It was already discovered, some time ago. That time from django stubs as well: python/mypy#8359

[sobolevn]

We can add a test-case with xfail for now. After mypy@1.6.0 we will just remove xfail and move on.

[UnknownPlatypus]

Hey, just chiming in to say I really appreciate all the work you all do on the plugin code to make it more reliable. Keep up the good work, would have loved to help you a bit but it's holidays season for me currently ahah.

Anyway, thanks!

[UnknownPlatypus]

I believe this was done in #2314