Improves README with new example repo, python version matrix

README.md

@@ -52,6 +52,12 @@ django_settings_module = mysettings
 
 Where `mysettings` is a value of `DJANGO_SETTINGS_MODULE` (with or without quotes)
 
+You might also need to explicitly tweak your `PYTHONPATH` the very same way `django` does it internally in case you have troubles with mypy / django plugin not finding your settings module. Try adding the root path of your project to your `PYTHONPATH` environment variable like so:
+
+```bash
+PYTHONPATH=${PYTHONPATH}:${PWD}
+```
+
 Current implementation uses Django runtime to extract models information, so it will crash, if your installed apps `models.py` is not correct. For this same reason, you cannot use `reveal_type` inside global scope of any Python file that will be executed for `django.setup()`. 
 
 In other words, if your `manage.py runserver` crashes, mypy will crash too. 

django-stubs/core/management/base.pyi

@@ -63,7 +63,7 @@ class BaseCommand:
         fail_level: int = ...,
     ) -> None: ...
     def check_migrations(self) -> None: ...
-    def handle(self, *args: Any, **options: Any) -> Optional[str]: ...
+    def handle(self, *args: Any, **options: Any) -> None: ...
 
 class AppCommand(BaseCommand):
     missing_args_message: str = ...

mypy_django_plugin/django/context.py

@@ -1,5 +1,4 @@
 import os
-import sys
 from collections import defaultdict
 from contextlib import contextmanager
 from typing import (
@@ -49,9 +48,6 @@ def initialize_django(settings_module: str) -> Tuple['Apps', 'LazySettings']:
     with temp_environ():
         os.environ['DJANGO_SETTINGS_MODULE'] = settings_module
 
-        # add current directory to sys.path
-        sys.path.append(os.getcwd())
-
         def noop_class_getitem(cls, key):
             return cls
 
@@ -77,12 +73,176 @@ def initialize_django(settings_module: str) -> Tuple['Apps', 'LazySettings']:
     return apps, settings
 
 
+class DjangoFieldsContext:
+    def __init__(self, django_context: 'DjangoContext') -> None:
+        self.django_context = django_context
+
+    def get_attname(self, field: Field) -> str:
+        attname = field.attname
+        return attname
+
+    def get_field_nullability(self, field: Field, method: Optional[str]) -> bool:
+        nullable = field.null
+        if not nullable and isinstance(field, CharField) and field.blank:
+            return True
+        if method == '__init__':
+            if field.primary_key or isinstance(field, ForeignKey):
+                return True
+        if method == 'create':
+            if isinstance(field, AutoField):
+                return True
+        if field.has_default():
+            return True
+        return nullable
+
+    def get_field_set_type(self, api: TypeChecker, field: Field, *, method: str) -> MypyType:
+        """ Get a type of __set__ for this specific Django field. """
+        target_field = field
+        if isinstance(field, ForeignKey):
+            target_field = field.target_field
+
+        field_info = helpers.lookup_class_typeinfo(api, target_field.__class__)
+        if field_info is None:
+            return AnyType(TypeOfAny.from_error)
+
+        field_set_type = helpers.get_private_descriptor_type(field_info, '_pyi_private_set_type',
+                                                             is_nullable=self.get_field_nullability(field, method))
+        if isinstance(target_field, ArrayField):
+            argument_field_type = self.get_field_set_type(api, target_field.base_field, method=method)
+            field_set_type = helpers.convert_any_to_type(field_set_type, argument_field_type)
+        return field_set_type
+
+    def get_field_get_type(self, api: TypeChecker, field: Field, *, method: str) -> MypyType:
+        """ Get a type of __get__ for this specific Django field. """
+        field_info = helpers.lookup_class_typeinfo(api, field.__class__)
+        if field_info is None:
+            return AnyType(TypeOfAny.unannotated)
+
+        is_nullable = self.get_field_nullability(field, method)
+        if isinstance(field, RelatedField):
+            related_model_cls = self.django_context.fields_context.get_related_model_cls(field)
+
+            if method == 'values':
+                primary_key_field = self.django_context.get_primary_key_field(related_model_cls)
+                return self.get_field_get_type(api, primary_key_field, method=method)
+
+            model_info = helpers.lookup_class_typeinfo(api, related_model_cls)
+            if model_info is None:
+                return AnyType(TypeOfAny.unannotated)
+
+            return Instance(model_info, [])
+        else:
+            return helpers.get_private_descriptor_type(field_info, '_pyi_private_get_type',
+                                                       is_nullable=is_nullable)
+
+    def get_related_model_cls(self, field: Union[RelatedField, ForeignObjectRel]) -> Type[Model]:
+        if isinstance(field, RelatedField):
+            related_model_cls = field.remote_field.model
+        else:
+            related_model_cls = field.field.model
+
+        if isinstance(related_model_cls, str):
+            if related_model_cls == 'self':
+                # same model
+                related_model_cls = field.model
+            elif '.' not in related_model_cls:
+                # same file model
+                related_model_fullname = field.model.__module__ + '.' + related_model_cls
+                related_model_cls = self.django_context.get_model_class_by_fullname(related_model_fullname)
+            else:
+                related_model_cls = self.django_context.apps_registry.get_model(related_model_cls)
+
+        return related_model_cls
+
+
 class LookupsAreUnsupported(Exception):
     pass
 
 
+class DjangoLookupsContext:
+    def __init__(self, django_context: 'DjangoContext'):
+        self.django_context = django_context
+
+    def _resolve_field_from_parts(self, field_parts: Iterable[str], model_cls: Type[Model]) -> Field:
+        currently_observed_model = model_cls
+        field = None
+        for field_part in field_parts:
+            if field_part == 'pk':
+                field = self.django_context.get_primary_key_field(currently_observed_model)
+                continue
+
+            field = currently_observed_model._meta.get_field(field_part)
+            if isinstance(field, RelatedField):
+                currently_observed_model = field.related_model
+                model_name = currently_observed_model._meta.model_name
+                if (model_name is not None
+                        and field_part == (model_name + '_id')):
+                    field = self.django_context.get_primary_key_field(currently_observed_model)
+
+            if isinstance(field, ForeignObjectRel):
+                currently_observed_model = field.related_model
+
+        assert field is not None
+        return field
+
+    def resolve_lookup_info_field(self, model_cls: Type[Model], lookup: str) -> Field:
+        query = Query(model_cls)
+        lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
+        if lookup_parts:
+            raise LookupsAreUnsupported()
+
+        return self._resolve_field_from_parts(field_parts, model_cls)
+
+    def resolve_lookup_expected_type(self, ctx: MethodContext, model_cls: Type[Model], lookup: str) -> MypyType:
+        query = Query(model_cls)
+        try:
+            lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
+            if is_expression:
+                return AnyType(TypeOfAny.explicit)
+        except FieldError as exc:
+            ctx.api.fail(exc.args[0], ctx.context)
+            return AnyType(TypeOfAny.from_error)
+
+        field = self._resolve_field_from_parts(field_parts, model_cls)
+
+        lookup_cls = None
+        if lookup_parts:
+            lookup = lookup_parts[-1]
+            lookup_cls = field.get_lookup(lookup)
+            if lookup_cls is None:
+                # unknown lookup
+                return AnyType(TypeOfAny.explicit)
+
+        if lookup_cls is None or isinstance(lookup_cls, Exact):
+            return self.django_context.get_field_lookup_exact_type(helpers.get_typechecker_api(ctx), field)
+
+        assert lookup_cls is not None
+
+        lookup_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), lookup_cls)
+        if lookup_info is None:
+            return AnyType(TypeOfAny.explicit)
+
+        for lookup_base in helpers.iter_bases(lookup_info):
+            if lookup_base.args and isinstance(lookup_base.args[0], Instance):
+                lookup_type: MypyType = lookup_base.args[0]
+                # if it's Field, consider lookup_type a __get__ of current field
+                if (isinstance(lookup_type, Instance)
+                        and lookup_type.type.fullname() == fullnames.FIELD_FULLNAME):
+                    field_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), field.__class__)
+                    if field_info is None:
+                        return AnyType(TypeOfAny.explicit)
+                    lookup_type = helpers.get_private_descriptor_type(field_info, '_pyi_private_get_type',
+                                                                      is_nullable=field.null)
+                return lookup_type
+
+        return AnyType(TypeOfAny.explicit)
+
+
 class DjangoContext:
     def __init__(self, django_settings_module: str) -> None:
+        self.fields_context = DjangoFieldsContext(self)
+        self.lookups_context = DjangoLookupsContext(self)
+
         self.django_settings_module = django_settings_module
 
         apps, settings = initialize_django(self.django_settings_module)
@@ -128,7 +288,7 @@ class DjangoContext:
         if isinstance(field, (RelatedField, ForeignObjectRel)):
             related_model_cls = field.related_model
             primary_key_field = self.get_primary_key_field(related_model_cls)
-            primary_key_type = self.get_field_get_type(api, primary_key_field, method='init')
+            primary_key_type = self.fields_context.get_field_get_type(api, primary_key_field, method='init')
 
             rel_model_info = helpers.lookup_class_typeinfo(api, related_model_cls)
             if rel_model_info is None:
@@ -159,13 +319,13 @@ class DjangoContext:
         # add pk if not abstract=True
         if not model_cls._meta.abstract:
             primary_key_field = self.get_primary_key_field(model_cls)
-            field_set_type = self.get_field_set_type(api, primary_key_field, method=method)
+            field_set_type = self.fields_context.get_field_set_type(api, primary_key_field, method=method)
             expected_types['pk'] = field_set_type
 
         for field in model_cls._meta.get_fields():
             if isinstance(field, Field):
                 field_name = field.attname
-                field_set_type = self.get_field_set_type(api, field, method=method)
+                field_set_type = self.fields_context.get_field_set_type(api, field, method=method)
                 expected_types[field_name] = field_set_type
 
                 if isinstance(field, ForeignKey):
@@ -176,11 +336,7 @@ class DjangoContext:
                         expected_types[field_name] = AnyType(TypeOfAny.unannotated)
                         continue
 
-                    related_model = self.get_field_related_model_cls(field)
-                    if related_model is None:
-                        expected_types[field_name] = AnyType(TypeOfAny.from_error)
-                        continue
-
+                    related_model = self.fields_context.get_related_model_cls(field)
                     if related_model._meta.proxy_for_model is not None:
                         related_model = related_model._meta.proxy_for_model
 
@@ -189,7 +345,7 @@ class DjangoContext:
                         expected_types[field_name] = AnyType(TypeOfAny.unannotated)
                         continue
 
-                    is_nullable = self.get_field_nullability(field, method)
+                    is_nullable = self.fields_context.get_field_nullability(field, method)
                     foreign_key_set_type = helpers.get_private_descriptor_type(foreign_key_info,
                                                                                '_pyi_private_set_type',
                                                                                is_nullable=is_nullable)
@@ -209,173 +365,13 @@ class DjangoContext:
         return expected_types
 
     @cached_property
-    def all_registered_model_classes(self) -> Set[Type[models.Model]]:
+    def model_base_classes(self) -> Set[str]:
         model_classes = self.apps_registry.get_models()
 
         all_model_bases = set()
         for model_cls in model_classes:
             for base_cls in model_cls.mro():
                 if issubclass(base_cls, models.Model):
-                    all_model_bases.add(base_cls)
+                    all_model_bases.add(helpers.get_class_fullname(base_cls))
 
         return all_model_bases
-
-    @cached_property
-    def all_registered_model_class_fullnames(self) -> Set[str]:
-        return {helpers.get_class_fullname(cls) for cls in self.all_registered_model_classes}
-
-    def get_attname(self, field: Field) -> str:
-        attname = field.attname
-        return attname
-
-    def get_field_nullability(self, field: Field, method: Optional[str]) -> bool:
-        nullable = field.null
-        if not nullable and isinstance(field, CharField) and field.blank:
-            return True
-        if method == '__init__':
-            if field.primary_key or isinstance(field, ForeignKey):
-                return True
-        if method == 'create':
-            if isinstance(field, AutoField):
-                return True
-        if field.has_default():
-            return True
-        return nullable
-
-    def get_field_set_type(self, api: TypeChecker, field: Field, *, method: str) -> MypyType:
-        """ Get a type of __set__ for this specific Django field. """
-        target_field = field
-        if isinstance(field, ForeignKey):
-            target_field = field.target_field
-
-        field_info = helpers.lookup_class_typeinfo(api, target_field.__class__)
-        if field_info is None:
-            return AnyType(TypeOfAny.from_error)
-
-        field_set_type = helpers.get_private_descriptor_type(field_info, '_pyi_private_set_type',
-                                                             is_nullable=self.get_field_nullability(field, method))
-        if isinstance(target_field, ArrayField):
-            argument_field_type = self.get_field_set_type(api, target_field.base_field, method=method)
-            field_set_type = helpers.convert_any_to_type(field_set_type, argument_field_type)
-        return field_set_type
-
-    def get_field_get_type(self, api: TypeChecker, field: Field, *, method: str) -> MypyType:
-        """ Get a type of __get__ for this specific Django field. """
-        field_info = helpers.lookup_class_typeinfo(api, field.__class__)
-        if field_info is None:
-            return AnyType(TypeOfAny.unannotated)
-
-        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)
-                return self.get_field_get_type(api, primary_key_field, method=method)
-
-            model_info = helpers.lookup_class_typeinfo(api, related_model_cls)
-            if model_info is None:
-                return AnyType(TypeOfAny.unannotated)
-
-            return Instance(model_info, [])
-        else:
-            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]) -> Optional[Type[Model]]:
-        if isinstance(field, RelatedField):
-            related_model_cls = field.remote_field.model
-        else:
-            related_model_cls = field.field.model
-
-        if isinstance(related_model_cls, str):
-            if related_model_cls == 'self':
-                # same model
-                related_model_cls = field.model
-            elif '.' not in related_model_cls:
-                # same file model
-                related_model_fullname = field.model.__module__ + '.' + related_model_cls
-                related_model_cls = self.get_model_class_by_fullname(related_model_fullname)
-            else:
-                related_model_cls = self.apps_registry.get_model(related_model_cls)
-
-        return related_model_cls
-
-    def _resolve_field_from_parts(self, field_parts: Iterable[str], model_cls: Type[Model]) -> Field:
-        currently_observed_model = model_cls
-        field = None
-        for field_part in field_parts:
-            if field_part == 'pk':
-                field = self.get_primary_key_field(currently_observed_model)
-                continue
-
-            field = currently_observed_model._meta.get_field(field_part)
-            if isinstance(field, RelatedField):
-                currently_observed_model = field.related_model
-                model_name = currently_observed_model._meta.model_name
-                if (model_name is not None
-                        and field_part == (model_name + '_id')):
-                    field = self.get_primary_key_field(currently_observed_model)
-
-            if isinstance(field, ForeignObjectRel):
-                currently_observed_model = field.related_model
-
-        assert field is not None
-        return field
-
-    def resolve_lookup_into_field(self, model_cls: Type[Model], lookup: str) -> Field:
-        query = Query(model_cls)
-        lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
-        if lookup_parts:
-            raise LookupsAreUnsupported()
-
-        return self._resolve_field_from_parts(field_parts, model_cls)
-
-    def resolve_lookup_expected_type(self, ctx: MethodContext, model_cls: Type[Model], lookup: str) -> MypyType:
-        query = Query(model_cls)
-        try:
-            lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
-            if is_expression:
-                return AnyType(TypeOfAny.explicit)
-        except FieldError as exc:
-            ctx.api.fail(exc.args[0], ctx.context)
-            return AnyType(TypeOfAny.from_error)
-
-        field = self._resolve_field_from_parts(field_parts, model_cls)
-
-        lookup_cls = None
-        if lookup_parts:
-            lookup = lookup_parts[-1]
-            lookup_cls = field.get_lookup(lookup)
-            if lookup_cls is None:
-                # unknown lookup
-                return AnyType(TypeOfAny.explicit)
-
-        if lookup_cls is None or isinstance(lookup_cls, Exact):
-            return self.get_field_lookup_exact_type(helpers.get_typechecker_api(ctx), field)
-
-        assert lookup_cls is not None
-
-        lookup_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), lookup_cls)
-        if lookup_info is None:
-            return AnyType(TypeOfAny.explicit)
-
-        for lookup_base in helpers.iter_bases(lookup_info):
-            if lookup_base.args and isinstance(lookup_base.args[0], Instance):
-                lookup_type: MypyType = lookup_base.args[0]
-                # if it's Field, consider lookup_type a __get__ of current field
-                if (isinstance(lookup_type, Instance)
-                        and lookup_type.type.fullname() == fullnames.FIELD_FULLNAME):
-                    field_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), field.__class__)
-                    if field_info is None:
-                        return AnyType(TypeOfAny.explicit)
-                    lookup_type = helpers.get_private_descriptor_type(field_info, '_pyi_private_get_type',
-                                                                      is_nullable=field.null)
-                return lookup_type
-
-        return AnyType(TypeOfAny.explicit)
-
-    def resolve_f_expression_type(self, f_expression_type: Instance) -> MypyType:
-        return AnyType(TypeOfAny.explicit)

mypy_django_plugin/lib/fullnames.py

@@ -37,5 +37,3 @@ RELATED_FIELDS_CLASSES = {
 MIGRATION_CLASS_FULLNAME = 'django.db.migrations.migration.Migration'
 OPTIONS_CLASS_FULLNAME = 'django.db.models.options.Options'
 HTTPREQUEST_CLASS_FULLNAME = 'django.http.request.HttpRequest'
-
-F_EXPRESSION_FULLNAME = 'django.db.models.expressions.F'

mypy_django_plugin/lib/helpers.py

@@ -282,25 +282,5 @@ def get_typechecker_api(ctx: Union[AttributeContext, MethodContext, FunctionCont
 
 
 def is_model_subclass_info(info: TypeInfo, django_context: 'DjangoContext') -> bool:
-    return (info.fullname() in django_context.all_registered_model_class_fullnames
+    return (info.fullname() in django_context.model_base_classes
             or info.has_base(fullnames.MODEL_CLASS_FULLNAME))
-
-
-def check_types_compatible(ctx: Union[FunctionContext, MethodContext],
-                           *, expected_type: MypyType, actual_type: MypyType, error_message: str) -> None:
-    api = get_typechecker_api(ctx)
-    api.check_subtype(actual_type, expected_type,
-                      ctx.context, error_message,
-                      'got', 'expected')
-
-
-def add_new_sym_for_info(info: TypeInfo, *, name: str, sym_type: MypyType) -> None:
-    # type=: type of the variable itself
-    var = Var(name=name, type=sym_type)
-    # var.info: type of the object variable is bound to
-    var.info = info
-    var._fullname = info.fullname() + '.' + name
-    var.is_initialized_in_class = True
-    var.is_inferred = True
-    info.names[name] = SymbolTableNode(MDEF, var,
-                                       plugin_generated=True)

mypy_django_plugin/main.py

@@ -11,7 +11,6 @@ from mypy.plugin import (
 )
 from mypy.types import Type as MypyType
 
-import mypy_django_plugin.transformers.orm_lookups
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.lib import fullnames, helpers
 from mypy_django_plugin.transformers import (
@@ -149,15 +148,13 @@ class NewSemanalDjangoPlugin(Plugin):
             # forward relations
             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_cls = self.django_context.fields_context.get_related_model_cls(field)
                     related_model_module = related_model_cls.__module__
                     if related_model_module != file.fullname():
                         deps.add(self._new_dependency(related_model_module))
             # reverse relations
             for relation in model_class._meta.related_objects:
-                related_model_cls = self.django_context.get_field_related_model_cls(relation)
+                related_model_cls = self.django_context.fields_context.get_related_model_cls(relation)
                 related_model_module = related_model_cls.__module__
                 if related_model_module != file.fullname():
                     deps.add(self._new_dependency(related_model_module))
@@ -213,13 +210,12 @@ class NewSemanalDjangoPlugin(Plugin):
         if class_fullname in manager_classes and method_name == 'create':
             return partial(init_create.redefine_and_typecheck_model_create, django_context=self.django_context)
         if class_fullname in manager_classes and method_name in {'filter', 'get', 'exclude'}:
-            return partial(mypy_django_plugin.transformers.orm_lookups.typecheck_queryset_filter,
-                           django_context=self.django_context)
+            return partial(init_create.typecheck_queryset_filter, django_context=self.django_context)
         return None
 
     def get_base_class_hook(self, fullname: str
                             ) -> Optional[Callable[[ClassDefContext], None]]:
-        if (fullname in self.django_context.all_registered_model_class_fullnames
+        if (fullname in self.django_context.model_base_classes
                 or fullname in self._get_current_model_bases()):
             return partial(transform_model_class, django_context=self.django_context)
 

mypy_django_plugin/transformers/fields.py

@@ -37,14 +37,6 @@ def _get_current_field_from_assignment(ctx: FunctionContext, django_context: Dja
     return current_field
 
 
-def reparametrize_related_field_type(related_field_type: Instance, set_type, get_type) -> Instance:
-    args = [
-        helpers.convert_any_to_type(related_field_type.args[0], set_type),
-        helpers.convert_any_to_type(related_field_type.args[1], get_type),
-    ]
-    return helpers.reparametrize_instance(related_field_type, new_args=args)
-
-
 def fill_descriptor_types_for_related_field(ctx: FunctionContext, django_context: DjangoContext) -> MypyType:
     current_field = _get_current_field_from_assignment(ctx, django_context)
     if current_field is None:
@@ -52,28 +44,7 @@ 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)
-
-    default_related_field_type = set_descriptor_types_for_field(ctx)
-
-    # self reference with abstract=True on the model where ForeignKey is defined
-    current_model_cls = current_field.model
-    if (current_model_cls._meta.abstract
-            and current_model_cls == related_model_cls):
-        # for all derived non-abstract classes, set variable with this name to
-        # __get__/__set__ of ForeignKey of derived model
-        for model_cls in django_context.all_registered_model_classes:
-            if issubclass(model_cls, current_model_cls) and not model_cls._meta.abstract:
-                derived_model_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), model_cls)
-                if derived_model_info is not None:
-                    fk_ref_type = Instance(derived_model_info, [])
-                    derived_fk_type = reparametrize_related_field_type(default_related_field_type,
-                                                                       set_type=fk_ref_type, get_type=fk_ref_type)
-                    helpers.add_new_sym_for_info(derived_model_info,
-                                                 name=current_field.name,
-                                                 sym_type=derived_fk_type)
+    related_model_cls = django_context.fields_context.get_related_model_cls(current_field)
 
     related_model = related_model_cls
     related_model_to_set = related_model_cls
@@ -96,10 +67,13 @@ def fill_descriptor_types_for_related_field(ctx: FunctionContext, django_context
     else:
         related_model_to_set_type = Instance(related_model_to_set_info, [])  # type: ignore
 
+    default_related_field_type = set_descriptor_types_for_field(ctx)
     # replace Any with referred_to_type
-    return reparametrize_related_field_type(default_related_field_type,
-                                            set_type=related_model_to_set_type,
-                                            get_type=related_model_type)
+    args = [
+        helpers.convert_any_to_type(default_related_field_type.args[0], related_model_to_set_type),
+        helpers.convert_any_to_type(default_related_field_type.args[1], related_model_type),
+    ]
+    return helpers.reparametrize_instance(default_related_field_type, new_args=args)
 
 
 def get_field_descriptor_types(field_info: TypeInfo, is_nullable: bool) -> Tuple[MypyType, MypyType]:

mypy_django_plugin/transformers/init_create.py

@@ -6,7 +6,7 @@ from mypy.types import Instance
 from mypy.types import Type as MypyType
 
 from mypy_django_plugin.django.context import DjangoContext
-from mypy_django_plugin.lib import helpers
+from mypy_django_plugin.lib import fullnames, helpers
 
 
 def get_actual_types(ctx: Union[MethodContext, FunctionContext],
@@ -30,6 +30,12 @@ def get_actual_types(ctx: Union[MethodContext, FunctionContext],
     return actual_types
 
 
+def check_types_compatible(ctx, *, expected_type, actual_type, error_message):
+    ctx.api.check_subtype(actual_type, expected_type,
+                          ctx.context, error_message,
+                          'got', 'expected')
+
+
 def typecheck_model_method(ctx: Union[FunctionContext, MethodContext], django_context: DjangoContext,
                            model_cls: Type[Model], method: str) -> MypyType:
     typechecker_api = helpers.get_typechecker_api(ctx)
@@ -42,11 +48,11 @@ def typecheck_model_method(ctx: Union[FunctionContext, MethodContext], django_co
                                                                            model_cls.__name__),
                          ctx.context)
             continue
-        helpers.check_types_compatible(ctx,
-                                       expected_type=expected_types[actual_name],
-                                       actual_type=actual_type,
-                                       error_message='Incompatible type for "{}" of "{}"'.format(actual_name,
-                                                                                                 model_cls.__name__))
+        check_types_compatible(ctx,
+                               expected_type=expected_types[actual_name],
+                               actual_type=actual_type,
+                               error_message='Incompatible type for "{}" of "{}"'.format(actual_name,
+                                                                                         model_cls.__name__))
 
     return ctx.default_return_type
 
@@ -73,3 +79,40 @@ def redefine_and_typecheck_model_create(ctx: MethodContext, django_context: Djan
         return ctx.default_return_type
 
     return typecheck_model_method(ctx, django_context, model_cls, 'create')
+
+
+def typecheck_queryset_filter(ctx: MethodContext, django_context: DjangoContext) -> MypyType:
+    lookup_kwargs = ctx.arg_names[1]
+    provided_lookup_types = ctx.arg_types[1]
+
+    assert isinstance(ctx.type, Instance)
+
+    if not ctx.type.args or not isinstance(ctx.type.args[0], Instance):
+        return ctx.default_return_type
+
+    model_cls_fullname = ctx.type.args[0].type.fullname()
+    model_cls = django_context.get_model_class_by_fullname(model_cls_fullname)
+    if model_cls is None:
+        return ctx.default_return_type
+
+    for lookup_kwarg, provided_type in zip(lookup_kwargs, provided_lookup_types):
+        if lookup_kwarg is None:
+            continue
+        # Combinables are not supported yet
+        if (isinstance(provided_type, Instance)
+                and provided_type.type.has_base('django.db.models.expressions.Combinable')):
+            continue
+
+        lookup_type = django_context.lookups_context.resolve_lookup_expected_type(ctx, model_cls, lookup_kwarg)
+        # Managers as provided_type is not supported yet
+        if (isinstance(provided_type, Instance)
+                and helpers.has_any_of_bases(provided_type.type, (fullnames.MANAGER_CLASS_FULLNAME,
+                                                                  fullnames.QUERYSET_CLASS_FULLNAME))):
+            return ctx.default_return_type
+
+        check_types_compatible(ctx,
+                               expected_type=lookup_type,
+                               actual_type=provided_type,
+                               error_message=f'Incompatible type for lookup {lookup_kwarg!r}:')
+
+    return ctx.default_return_type

mypy_django_plugin/transformers/models.py

@@ -7,12 +7,12 @@ from django.db.models.fields.related import ForeignKey
 from django.db.models.fields.reverse_related import (
     ManyToManyRel, ManyToOneRel, OneToOneRel,
 )
-from mypy.nodes import ARG_STAR2, Argument, Context, TypeInfo, Var
+from mypy.nodes import (
+    ARG_STAR2, MDEF, Argument, SymbolTableNode, TypeInfo, Var,
+)
 from mypy.plugin import ClassDefContext
 from mypy.plugins import common
-from mypy.types import AnyType, Instance
-from mypy.types import Type as MypyType
-from mypy.types import TypeOfAny
+from mypy.types import AnyType, Instance, TypeOfAny
 
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.lib import fullnames, helpers
@@ -38,7 +38,7 @@ class ModelClassInitializer:
         field_info = self.lookup_typeinfo_or_incomplete_defn_error(fullname)
         return field_info
 
-    def create_new_var(self, name: str, typ: MypyType) -> Var:
+    def create_new_var(self, name: str, typ: Instance) -> Var:
         # type=: type of the variable itself
         var = Var(name=name, type=typ)
         # var.info: type of the object variable is bound to
@@ -48,10 +48,9 @@ class ModelClassInitializer:
         var.is_inferred = True
         return var
 
-    def add_new_node_to_model_class(self, name: str, typ: MypyType) -> None:
-        helpers.add_new_sym_for_info(self.model_classdef.info,
-                                     name=name,
-                                     sym_type=typ)
+    def add_new_node_to_model_class(self, name: str, typ: Instance) -> None:
+        var = self.create_new_var(name, typ)
+        self.model_classdef.info.names[name] = SymbolTableNode(MDEF, var, plugin_generated=True)
 
     def run(self) -> None:
         model_cls = self.django_context.get_model_class_by_fullname(self.model_classdef.fullname)
@@ -100,25 +99,10 @@ class AddRelatedModelsId(ModelClassInitializer):
     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
-
-                if related_model_cls._meta.abstract:
-                    continue
-
+                related_model_cls = self.django_context.fields_context.get_related_model_cls(field)
                 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)
+                is_nullable = self.django_context.fields_context.get_field_nullability(field, None)
                 set_type, get_type = get_field_descriptor_types(field_info, is_nullable)
                 self.add_new_node_to_model_class(field.attname,
                                                  Instance(field_info, [set_type, get_type]))
@@ -178,11 +162,9 @@ class AddRelatedManagers(ModelClassInitializer):
                 # no reverse accessor
                 continue
 
-            related_model_cls = self.django_context.get_field_related_model_cls(relation)
-            if related_model_cls is None:
-                continue
-
+            related_model_cls = self.django_context.fields_context.get_related_model_cls(relation)
             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/orm_lookups.py

@@ -1,51 +0,0 @@
-from mypy.plugin import MethodContext
-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
-
-
-def typecheck_queryset_filter(ctx: MethodContext, django_context: DjangoContext) -> MypyType:
-    lookup_kwargs = ctx.arg_names[1]
-    provided_lookup_types = ctx.arg_types[1]
-
-    assert isinstance(ctx.type, Instance)
-
-    if not ctx.type.args or not isinstance(ctx.type.args[0], Instance):
-        return ctx.default_return_type
-
-    model_cls_fullname = ctx.type.args[0].type.fullname()
-    model_cls = django_context.get_model_class_by_fullname(model_cls_fullname)
-    if model_cls is None:
-        return ctx.default_return_type
-
-    for lookup_kwarg, provided_type in zip(lookup_kwargs, provided_lookup_types):
-        if lookup_kwarg is None:
-            continue
-        if (isinstance(provided_type, Instance)
-                and provided_type.type.has_base('django.db.models.expressions.Combinable')):
-            provided_type = resolve_combinable_type(provided_type, django_context)
-
-        lookup_type = django_context.resolve_lookup_expected_type(ctx, model_cls, lookup_kwarg)
-        # Managers as provided_type is not supported yet
-        if (isinstance(provided_type, Instance)
-                and helpers.has_any_of_bases(provided_type.type, (fullnames.MANAGER_CLASS_FULLNAME,
-                                                                  fullnames.QUERYSET_CLASS_FULLNAME))):
-            return ctx.default_return_type
-
-        helpers.check_types_compatible(ctx,
-                                       expected_type=lookup_type,
-                                       actual_type=provided_type,
-                                       error_message=f'Incompatible type for lookup {lookup_kwarg!r}:')
-
-    return ctx.default_return_type
-
-
-def resolve_combinable_type(combinable_type: Instance, django_context: DjangoContext) -> MypyType:
-    if combinable_type.type.fullname() != fullnames.F_EXPRESSION_FULLNAME:
-        # Combinables aside from F expressions are unsupported
-        return AnyType(TypeOfAny.explicit)
-
-    return django_context.resolve_f_expression_type(combinable_type)

mypy_django_plugin/transformers/querysets.py

@@ -40,7 +40,7 @@ def determine_proper_manager_type(ctx: FunctionContext) -> MypyType:
 def get_field_type_from_lookup(ctx: MethodContext, django_context: DjangoContext, model_cls: Type[Model],
                                *, method: str, lookup: str) -> Optional[MypyType]:
     try:
-        lookup_field = django_context.resolve_lookup_into_field(model_cls, lookup)
+        lookup_field = django_context.lookups_context.resolve_lookup_info_field(model_cls, lookup)
     except FieldError as exc:
         ctx.api.fail(exc.args[0], ctx.context)
         return None
@@ -48,13 +48,11 @@ def get_field_type_from_lookup(ctx: MethodContext, django_context: DjangoContext
         return AnyType(TypeOfAny.explicit)
 
     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)
+        related_model_cls = django_context.fields_context.get_related_model_cls(lookup_field)
         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),
-                                                       lookup_field, method=method)
+    field_get_type = django_context.fields_context.get_field_get_type(helpers.get_typechecker_api(ctx),
+                                                                      lookup_field, method=method)
     return field_get_type
 
 
@@ -75,8 +73,8 @@ def get_values_list_row_type(ctx: MethodContext, django_context: DjangoContext,
         elif named:
             column_types: 'OrderedDict[str, MypyType]' = OrderedDict()
             for field in django_context.get_model_fields(model_cls):
-                column_type = django_context.get_field_get_type(typechecker_api, field,
-                                                                method='values_list')
+                column_type = django_context.fields_context.get_field_get_type(typechecker_api, field,
+                                                                               method='values_list')
                 column_types[field.attname] = column_type
             return helpers.make_oneoff_named_tuple(typechecker_api, 'Row', column_types)
         else:

setup.py

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

test-data/typecheck/fields/test_related.yml

@@ -387,52 +387,22 @@
                 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_app
+-   case: if_model_is_defined_as_name_of_the_class_look_for_it_in_the_same_file
     main: |
         from myapp.models import Book
-        reveal_type(Book().publisher)  # N: Revealed type is 'myapp.models.publisher.Publisher*'
+        reveal_type(Book().publisher)  # N: Revealed type is 'myapp.models.Publisher*'
     installed_apps:
         - myapp
     files:
         -   path: myapp/__init__.py
-        -   path: myapp/models/__init__.py
-            content: |
-                from .publisher import Publisher
-                from .book import Book
-        -   path: myapp/models/publisher.py
+        -   path: myapp/models.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
@@ -624,27 +594,3 @@
                     transaction = models.ForeignKey(Transaction, on_delete=models.CASCADE)
 
                 Transaction().test()
-
-
--   case: resolve_primary_keys_for_foreign_keys_with_abstract_self_model
-    main: |
-        from myapp.models import User
-        reveal_type(User().parent)  # N: Revealed type is 'myapp.models.User*'
-        reveal_type(User().parent_id)  # N: Revealed type is 'builtins.int*'
-
-        reveal_type(User().parent2)  # N: Revealed type is 'Union[myapp.models.User, None]'
-        reveal_type(User().parent2_id)  # N: Revealed type is 'Union[builtins.int, None]'
-    installed_apps:
-        - myapp
-    files:
-        -   path: myapp/__init__.py
-        -   path: myapp/models.py
-            content: |
-                from django.db import models
-                class AbstractUser(models.Model):
-                    parent = models.ForeignKey('self', on_delete=models.CASCADE)
-                    parent2 = models.ForeignKey('self', null=True, on_delete=models.CASCADE)
-                    class Meta:
-                        abstract = True
-                class User(AbstractUser):
-                    pass

test-data/typecheck/managers/querysets/test_filter.yml

@@ -213,44 +213,3 @@
                     pass
                 class Profile(models.Model):
                     user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='profile')
-
-
-# TODO
--   case: f_expression_simple_case
-    main: |
-        from myapp.models import User
-        from django.db import models
-        User.objects.filter(username=models.F('username2'))
-        User.objects.filter(username=models.F('age'))
-    installed_apps:
-        - myapp
-    files:
-        -   path: myapp/__init__.py
-        -   path: myapp/models.py
-            content: |
-                from django.db import models
-
-                class User(models.Model):
-                    username = models.TextField()
-                    username2 = models.TextField()
-
-                    age = models.IntegerField()
-
-
-# TODO
--   case: f_expression_with_expression_math_is_not_supported
-    main: |
-        from myapp.models import User
-        from django.db import models
-        User.objects.filter(username=models.F('username2') + 'hello')
-    installed_apps:
-        - myapp
-    files:
-        -   path: myapp/__init__.py
-        -   path: myapp/models.py
-            content: |
-                from django.db import models
-                class User(models.Model):
-                    username = models.TextField()
-                    username2 = models.TextField()
-                    age = models.IntegerField()