Auto-inherit from TypedModelMeta

Author: UnknownPlatypus

mypy_django_plugin/lib/fullnames.py

@@ -56,7 +56,7 @@
 F_EXPRESSION_FULLNAME = "django.db.models.expressions.F"
 
 ANY_ATTR_ALLOWED_CLASS_FULLNAME = "django_stubs_ext.AnyAttrAllowed"
-
+TYPED_MODEL_META_FULLNAME = "django_stubs_ext.db.models.TypedModelMeta"
 STR_PROMISE_FULLNAME = "django.utils.functional._StrPromise"
 
 OBJECT_DOES_NOT_EXIST = "django.core.exceptions.ObjectDoesNotExist"

mypy_django_plugin/main.py

@@ -125,9 +125,11 @@ def get_additional_deps(self, file: MypyFile) -> list[tuple[int, str, int]]:
                     deps.add(self._new_dependency(related_model_module))
 
         return list(deps) + [
-            # for QuerySet.annotate
+            # For `QuerySet.annotate`
             self._new_dependency("django_stubs_ext"),
-            # For Manager.from_queryset
+            # For `TypedModelMeta` lookup in model transformers
+            self._new_dependency("django_stubs_ext.db.models"),
+            # For `Manager.from_queryset`
             self._new_dependency("django.db.models.query"),
         ]
 

mypy_django_plugin/transformers/models.py

@@ -262,16 +262,27 @@ class Meta:
                 pass
     with
         class MyModel(models.Model):
-            class Meta(Any):
+            class Meta(TypedModelMeta):
                 pass
+
+    to provide proper typing of attributes in Meta inner classes.
+
+    If TypedModelMeta is not available, fallback to Any as a base
     to get around incompatible Meta inner classes for different models.
     """
 
     def run(self) -> None:
         meta_node = helpers.get_nested_meta_node_for_current_class(self.model_classdef.info)
         if meta_node is None:
             return None
-        meta_node.fallback_to_any = True
+
+        typed_model_meta_info = self.lookup_typeinfo(fullnames.TYPED_MODEL_META_FULLNAME)
+        if typed_model_meta_info and not meta_node.has_base(fullnames.TYPED_MODEL_META_FULLNAME):
+            # Insert TypedModelMeta just before `object` to leverage mypy's class-body semantic analysis.
+            meta_node.mro.insert(-1, typed_model_meta_info)
+        else:
+            meta_node.fallback_to_any = True
+        return None
 
 
 class AddDefaultPrimaryKey(ModelClassInitializer):

tests/typecheck/models/test_meta_options.yml

@@ -76,6 +76,59 @@
                 unique_together = {1: 2}  # E: Incompatible types in assignment (expression has type "dict[int, int]", base class "TypedModelMeta" defined the type as "Sequence[Sequence[str]]")  [assignment]
                 unknown_attr = True  # can't check this
 
+        class MyModelMultipleBaseMeta(models.Model):
+          class Meta(MyModel.Meta, TypedModelMeta):
+              abstract = 7  # E: Incompatible types in assignment (expression has type "int", base class "TypedModelMeta" defined the type as "bool")  [assignment]
+
+-   case: auto_base_model_meta_incompatible_types
+    main: |
+        from myapp.models import MyModelWithAutoTypedMeta
+    installed_apps:
+      - myapp
+    files:
+      - path: myapp/__init__.py
+      - path: myapp/models.py
+        content: |
+            from django.db import models
+
+            class MyModelWithAutoTypedMeta(models.Model):
+                example = models.CharField(max_length=100)
+                class Meta:
+                    abstract = 7  # E: Incompatible types in assignment (expression has type "int", base class "TypedModelMeta" defined the type as "bool")  [assignment]
+                    verbose_name = ['test']  # E: Incompatible types in assignment (expression has type "list[str]", base class "TypedModelMeta" defined the type as "str | _StrPromise")  [assignment]
+                    unique_together = {1: 2}  # E: Incompatible types in assignment (expression has type "dict[int, int]", base class "TypedModelMeta" defined the type as "Sequence[Sequence[str]]")  [assignment]
+
+            class DefinitelyNotAModel:
+                class Meta:
+                    abstract = 7
+                    verbose_name = ['test']
+                    unique_together = {1: 2}
+                    unknown_attr = True
+
+-   case: auto_base_model_meta_incompatible_types_multiple_inheritance
+    main: |
+        from myapp.models import MyModel, MyModel2, MyModel3
+    installed_apps:
+      - myapp
+    files:
+      - path: myapp/__init__.py
+      - path: myapp/models.py
+        content: |
+            from django.db import models
+
+            class MyModel(models.Model):
+                class Meta:
+                    abstract = 5  # E: Incompatible types in assignment (expression has type "int", base class "TypedModelMeta" defined the type as "bool")  [assignment]
+
+            class MyModel2(models.Model):
+                class Meta:
+                    abstract = 5  # E: Incompatible types in assignment (expression has type "int", base class "TypedModelMeta" defined the type as "bool")  [assignment]
+
+            class MyModel3(models.Model):
+                class Meta(MyModel.Meta, MyModel2.Meta):
+                    abstract = 7  # Ok because both base class declare int currently
+                    verbose_name = ['test']  # E: Incompatible types in assignment (expression has type "list[str]", base class "TypedModelMeta" defined the type as "str | _StrPromise")  [assignment]
+                    unique_together = {1: 2}  # E: Incompatible types in assignment (expression has type "dict[int, int]", base class "TypedModelMeta" defined the type as "Sequence[Sequence[str]]")  [assignment]
 
 -   case: instantiate_abstract_model
     main: |