Update _default_manager and _base_manager to be Manager

[flaeppe]

Default behaviour can be verified with the following snippet:

from django.db import models
class MyModel(models.Model):
    ...
print(type(MyModel._default_manager))  # <class 'django.db.models.manager.Manager'>
print(type(MyModel._base_manager))  # <class 'django.db.models.manager.Manager'>

Check e.g. Django _base_manager implementation

[sobolevn]

Thanks! I disabled these annoying annotations in #2023

[sobolevn]

Question: are we sure that there are no other cases where this can behave in a different way and return BaseManager? (I don't think so, just double checking)

[flaeppe]

_default_manager is completely dynamic and you can change it by setting default_manager_name = under class Meta. But the default behaviour is to return Manager (the implicit objects manager Django adds per default). I think the reason we've declared _default_manager in the stubs is for convenience

[sobolevn]

Ok 👍

[intgr]

There is some precedent to this as well:

• Restore RelatedManager, ManyRelatedManager to inherit from Manager not BaseManager #1843
• BaseManager rejected in DRF: Replace Manager with BaseManager djangorestframework-stubs#508

It's true that users can override manager with a class that doesn't derive from Manager. I'm not sure how prevalent that is.

• In most cases managers do derive from Manager.
• The existence of BaseManager isn't even documented in Django.
• Currently many APIs (e.g. get_object_or_404()) expect QuerySet[T] | Manager[T] as input, which isn't satisfied by BaseManager.

[flaeppe]

Thanks for digging up those links and info @intgr I'll go ahead and merge this