Expand override manager create test + move to assert_type

tests/assert_type/db/models/test_manager_overrides/models.py

@@ -0,0 +1,75 @@
+"""Overriding `Manager.create()` with a narrowed return type.
+
+Regression test for https://github.com/typeddjango/django-stubs/issues/578.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+from django.db import models
+from typing_extensions import assert_type, override
+
+# ---------------------------------------------------------------------------
+# Unparametrized manager: the plugin re-parametrizes it with the model it's on
+# ---------------------------------------------------------------------------
+
+
+class ArticleManager(models.Manager):  # pyright: ignore[reportMissingTypeArgument]
+    # Without a type parameter, the inherited `create()` returns the unsolved `_T`, so narrowing it is an error.
+    # Only mypy checks the override against `_T`, the other type checkers treat it as unknown.
+    @override
+    def create(self, **kwargs: Any) -> Article:  # type: ignore[override]
+        return super().create(**kwargs)  # type: ignore[return-value]  # pyright: ignore[reportUnknownVariableType]
+
+
+class Article(models.Model):
+    objects = ArticleManager()
+
+
+def override_manager_create_no_type_param() -> None:
+    assert_type(Article.objects.create(), Article)
+
+
+# ---------------------------------------------------------------------------
+# Manager parametrized with the model it's assigned to
+# ---------------------------------------------------------------------------
+
+
+class BookManager(models.Manager["Book"]):
+    @override
+    def create(self, **kwargs: Any) -> Book:
+        return super().create(**kwargs)
+
+
+class Book(models.Model):
+    # pyrefly doesn't solve `Self` in the `objects: ClassVar[Manager[Self]]` declaration
+    objects = BookManager()  # pyrefly: ignore[bad-assignment]
+
+
+def override_manager_create_with_type_param() -> None:
+    assert_type(Book.objects.create(), Book)
+
+
+# ---------------------------------------------------------------------------
+# Manager parametrized with another model than the one it's assigned to
+# ---------------------------------------------------------------------------
+
+
+class ReviewManager(models.Manager["Author"]):
+    # The type parameter, not the model the manager ends up on, drives what the inherited `create()` returns.
+    @override
+    def create(self, **kwargs: Any) -> Review:  # type: ignore[override]  # pyright: ignore[reportIncompatibleMethodOverride]  # pyrefly: ignore[bad-override]  # ty: ignore[invalid-method-override]
+        return super().create(**kwargs)  # type: ignore[return-value]  # pyright: ignore[reportReturnType]  # pyrefly: ignore[bad-return]  # ty: ignore[invalid-return-type]
+
+
+class Review(models.Model):
+    objects = ReviewManager()  # pyright: ignore[reportGeneralTypeIssues]  # pyrefly: ignore[bad-assignment]
+
+
+class Author(models.Model):
+    pass
+
+
+def override_manager_create_with_incoherent_type_param() -> None:
+    assert_type(Review.objects.create(), Review)

tests/typecheck/managers/test_managers.yml

@@ -401,54 +401,6 @@
                     movie = models.TextField()
 
 
--   case: override_manager_create1
-    main: |
-        from myapp.models import MyModel
-    installed_apps:
-        - myapp
-    out: |
-        myapp/models:7: error: Return type "MyModel" of "create" incompatible with return type "_T" in supertype "django.db.models.manager.Manager"  [override]
-        myapp/models:8: error: Incompatible return value type (got "_T", expected "MyModel")  [return-value]
-    files:
-        -   path: myapp/__init__.py
-        -   path: myapp/models.py
-            content: |
-                from typing import Any
-                from django.db import models
-                from typing_extensions import override
-
-                class MyModelManager(models.Manager):
-                    @override
-                    def create(self, **kwargs: Any) -> 'MyModel':
-                        return super().create(**kwargs)
-
-
-                class MyModel(models.Model):
-                    objects = MyModelManager()
-
-
--   case: override_manager_create2
-    main: |
-        from myapp.models import MyModel
-        MyModel.objects.create()
-    installed_apps:
-        - myapp
-    files:
-        -   path: myapp/__init__.py
-        -   path: myapp/models.py
-            content: |
-                from typing import Any
-                from django.db import models
-                from typing_extensions import override
-
-                class MyModelManager(models.Manager['MyModel']):
-                    @override
-                    def create(self, **kwargs: Any) -> 'MyModel':
-                        return super().create(**kwargs)
-
-                class MyModel(models.Model):
-                    objects = MyModelManager()
-
 -   case: regression_manager_scope_foreign
     main: |
         from typing_extensions import reveal_type