Support inheriting manager classes created via .from_queryset
#1699
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The changes here allows creation of managers looking like below
```python
class MyQuerySet(models.QuerySet["MyModel"]):
...
MyManager = models.Manager.from_queryset(MyQuerySet)
class MyOtherManager(MyManager):
...
```
| @@ -642,8 +642,8 @@ | |||
| reveal_type(user.article_set) # N: Revealed type is "myapp.models.Article_RelatedManager" | |||
| reveal_type(user.book_set.add) # N: Revealed type is "def (*objs: Union[myapp.models.Book, builtins.int], *, bulk: builtins.bool =)" | |||
| reveal_type(user.article_set.add) # N: Revealed type is "def (*objs: Union[myapp.models.Article, builtins.int], *, bulk: builtins.bool =)" | |||
| reveal_type(user.book_set.filter) # N: Revealed type is "def (*args: Any, **kwargs: Any) -> myapp.models.LibraryEntityQuerySet[myapp.models.Book]" | |||
| reveal_type(user.article_set.filter) # N: Revealed type is "def (*args: Any, **kwargs: Any) -> myapp.models.LibraryEntityQuerySet[myapp.models.Article]" | |||
| reveal_type(user.book_set.filter) # N: Revealed type is "def (*args: Any, **kwargs: Any) -> myapp.models.LibraryEntityQuerySet" | |||
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Yeah, I think this is a chain reaction of a bug that was revealed. Might be better to push it as a separate PR though.
The below change is the reason, in mypy_django_plugin/transformers/managers.py
- manager_type_info = manager_instance.type
+ manager_type_info = manager_instance.type.get_containing_type_info(method_name)There was a problem hiding this comment.
Right, think I figured it out. The change there takes a more correct path. There's nothing generic on the related managers, their model arguments are already populated on parent class(es). It becomes more obvious when using .get and seeing what model is returned. So I'll add that.
| @@ -310,7 +310,7 @@ | |||
| - case: handles_type_collision_with_from_queryset | |||
| main: | | |||
| from myapp.models import MyModel, FromQuerySet | |||
| reveal_type(FromQuerySet) # N: Revealed type is "def [_T <: django.db.models.base.Model] () -> myapp.models.ManagerFromModelQuerySet[_T`1]" | |||
| reveal_type(FromQuerySet) # N: Revealed type is "def () -> myapp.models.ManagerFromModelQuerySet[_T`1]" | |||
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Hm, yeah, gotta look in to that. But I'm not so sure there should be any arguments here. It might be, if we implicitly copy the manager argument to the new subclass created. It's all a bit blurry, since it needs to align with the model argument of the queryset etc.
I have made things!
The changes here allows creation of managers looking like below
I'll be honest here and will be saying that this is a bit controversial, because we kind of enforce mypy to interpret this kind of line:
As a
TypeAlias. The only thing I have to back up the changes here, apart from that runtime wise it's actually a type alias that is created, is here: python/mypy#8897 (comment)In our case it's not too dynamic as our plugin can resolve the
.from_querysetcall. But I haven't found any other tool that we can work with to make the generated type inheritable.