Fix crash if model from same app referenced in RelatedField cannot be resolved (#199)

* do not crash if model from same app refd in ForeignKey cannot be resolved

* bump to 1.2.0

Author: mkurnikov

mypy_django_plugin/django/context.py

@@ -177,6 +177,10 @@ def get_expected_types(self, api: TypeChecker, model_cls: Type[Model], *, method
                         continue
 
                     related_model = self.get_field_related_model_cls(field)
+                    if related_model is None:
+                        expected_types[field_name] = AnyType(TypeOfAny.from_error)
+                        continue
+
                     if related_model._meta.proxy_for_model is not None:
                         related_model = related_model._meta.proxy_for_model
 
@@ -260,6 +264,8 @@ def get_field_get_type(self, api: TypeChecker, field: Field, *, method: str) ->
         is_nullable = self.get_field_nullability(field, method)
         if isinstance(field, RelatedField):
             related_model_cls = self.get_field_related_model_cls(field)
+            if related_model_cls is None:
+                return AnyType(TypeOfAny.from_error)
 
             if method == 'values':
                 primary_key_field = self.get_primary_key_field(related_model_cls)
@@ -274,7 +280,7 @@ def get_field_get_type(self, api: TypeChecker, field: Field, *, method: str) ->
             return helpers.get_private_descriptor_type(field_info, '_pyi_private_get_type',
                                                        is_nullable=is_nullable)
 
-    def get_field_related_model_cls(self, field: Union[RelatedField, ForeignObjectRel]) -> Type[Model]:
+    def get_field_related_model_cls(self, field: Union[RelatedField, ForeignObjectRel]) -> Optional[Type[Model]]:
         if isinstance(field, RelatedField):
             related_model_cls = field.remote_field.model
         else:

mypy_django_plugin/main.py

@@ -150,6 +150,8 @@ def get_additional_deps(self, file: MypyFile) -> List[Tuple[int, str, int]]:
             for field in self.django_context.get_model_fields(model_class):
                 if isinstance(field, RelatedField):
                     related_model_cls = self.django_context.get_field_related_model_cls(field)
+                    if related_model_cls is None:
+                        continue
                     related_model_module = related_model_cls.__module__
                     if related_model_module != file.fullname():
                         deps.add(self._new_dependency(related_model_module))

mypy_django_plugin/transformers/fields.py

@@ -45,6 +45,8 @@ def fill_descriptor_types_for_related_field(ctx: FunctionContext, django_context
     assert isinstance(current_field, RelatedField)
 
     related_model_cls = django_context.get_field_related_model_cls(current_field)
+    if related_model_cls is None:
+        return AnyType(TypeOfAny.from_error)
 
     related_model = related_model_cls
     related_model_to_set = related_model_cls

mypy_django_plugin/transformers/models.py

@@ -8,11 +8,13 @@
     ManyToManyRel, ManyToOneRel, OneToOneRel,
 )
 from mypy.nodes import (
-    ARG_STAR2, MDEF, Argument, SymbolTableNode, TypeInfo, Var,
+    ARG_STAR2, MDEF, Argument, Context, SymbolTableNode, TypeInfo, Var,
 )
 from mypy.plugin import ClassDefContext
 from mypy.plugins import common
-from mypy.types import AnyType, Instance, TypeOfAny
+from mypy.types import AnyType, Instance
+from mypy.types import Type as MypyType
+from mypy.types import TypeOfAny
 
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.lib import fullnames, helpers
@@ -38,7 +40,7 @@ def lookup_class_typeinfo_or_incomplete_defn_error(self, klass: type) -> TypeInf
         field_info = self.lookup_typeinfo_or_incomplete_defn_error(fullname)
         return field_info
 
-    def create_new_var(self, name: str, typ: Instance) -> Var:
+    def create_new_var(self, name: str, typ: MypyType) -> Var:
         # type=: type of the variable itself
         var = Var(name=name, type=typ)
         # var.info: type of the object variable is bound to
@@ -48,7 +50,7 @@ def create_new_var(self, name: str, typ: Instance) -> Var:
         var.is_inferred = True
         return var
 
-    def add_new_node_to_model_class(self, name: str, typ: Instance) -> None:
+    def add_new_node_to_model_class(self, name: str, typ: MypyType) -> None:
         var = self.create_new_var(name, typ)
         self.model_classdef.info.names[name] = SymbolTableNode(MDEF, var, plugin_generated=True)
 
@@ -100,6 +102,18 @@ def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         for field in model_cls._meta.get_fields():
             if isinstance(field, ForeignKey):
                 related_model_cls = self.django_context.get_field_related_model_cls(field)
+                if related_model_cls is None:
+                    error_context: Context = self.ctx.cls
+                    field_sym = self.ctx.cls.info.get(field.name)
+                    if field_sym is not None and field_sym.node is not None:
+                        error_context = field_sym.node
+                    self.api.fail(f'Cannot find model {field.related_model!r} '
+                                  f'referenced in field {field.name!r} ',
+                                  ctx=error_context)
+                    self.add_new_node_to_model_class(field.attname,
+                                                     AnyType(TypeOfAny.explicit))
+                    continue
+
                 rel_primary_key_field = self.django_context.get_primary_key_field(related_model_cls)
                 field_info = self.lookup_class_typeinfo_or_incomplete_defn_error(rel_primary_key_field.__class__)
                 is_nullable = self.django_context.get_field_nullability(field, None)
@@ -163,8 +177,10 @@ def run_with_model_cls(self, model_cls: Type[Model]) -> None:
                 continue
 
             related_model_cls = self.django_context.get_field_related_model_cls(relation)
-            related_model_info = self.lookup_class_typeinfo_or_incomplete_defn_error(related_model_cls)
+            if related_model_cls is None:
+                continue
 
+            related_model_info = self.lookup_class_typeinfo_or_incomplete_defn_error(related_model_cls)
             if isinstance(relation, OneToOneRel):
                 self.add_new_node_to_model_class(attname, Instance(related_model_info, []))
                 continue

mypy_django_plugin/transformers/querysets.py

@@ -49,6 +49,8 @@ def get_field_type_from_lookup(ctx: MethodContext, django_context: DjangoContext
 
     if isinstance(lookup_field, RelatedField) and lookup_field.column == lookup:
         related_model_cls = django_context.get_field_related_model_cls(lookup_field)
+        if related_model_cls is None:
+            return AnyType(TypeOfAny.from_error)
         lookup_field = django_context.get_primary_key_field(related_model_cls)
 
     field_get_type = django_context.get_field_get_type(helpers.get_typechecker_api(ctx),

setup.py

@@ -21,14 +21,14 @@ def find_stub_files(name: str) -> List[str]:
     readme = f.read()
 
 dependencies = [
-    'mypy>=0.730,<0.740',
+    'mypy>=0.730',
     'typing-extensions',
     'django',
 ]
 
 setup(
     name="django-stubs",
-    version="1.1.0",
+    version="1.2.0",
     description='Mypy stubs for Django',
     long_description=readme,
     long_description_content_type='text/markdown',

test-data/typecheck/fields/test_related.yml

@@ -387,22 +387,52 @@
                 class Book2(models.Model):
                     publisher = models.ForeignKey(to=Publisher2, on_delete=models.CASCADE)
 
--   case: if_model_is_defined_as_name_of_the_class_look_for_it_in_the_same_file
+-   case: if_model_is_defined_as_name_of_the_class_look_for_it_in_the_same_app
     main: |
         from myapp.models import Book
-        reveal_type(Book().publisher)  # N: Revealed type is 'myapp.models.Publisher*'
+        reveal_type(Book().publisher)  # N: Revealed type is 'myapp.models.publisher.Publisher*'
     installed_apps:
         - myapp
     files:
         -   path: myapp/__init__.py
-        -   path: myapp/models.py
+        -   path: myapp/models/__init__.py
+            content: |
+                from .publisher import Publisher
+                from .book import Book
+        -   path: myapp/models/publisher.py
             content: |
                 from django.db import models
                 class Publisher(models.Model):
                     pass
+        -   path: myapp/models/book.py
+            content: |
+                from django.db import models
                 class Book(models.Model):
                     publisher = models.ForeignKey(to='Publisher', on_delete=models.CASCADE)
 
+
+-   case: fail_if_no_model_in_the_same_app_models_init_py
+    main: |
+        from myapp.models import Book
+    installed_apps:
+        - myapp
+    files:
+        -   path: myapp/__init__.py
+        -   path: myapp/models/__init__.py
+            content: |
+                from .book import Book
+        -   path: myapp/models/publisher.py
+            content: |
+                from django.db import models
+                class Publisher(models.Model):
+                    pass
+        -   path: myapp/models/book.py
+            content: |
+                from django.db import models
+                class Book(models.Model):
+                    publisher = models.ForeignKey(to='Publisher', on_delete=models.CASCADE)  # E: Cannot find model 'Publisher' referenced in field 'publisher'
+
+
 -   case: test_foreign_key_field_without_backwards_relation
     main: |
         from myapp.models import Book, Publisher