add Model.__init__ typechecking

mypy_django_plugin/plugins/fields.py

@@ -1,13 +1,12 @@
 from mypy.plugin import FunctionContext
 from mypy.types import Type, Instance
 
+from mypy_django_plugin import helpers
+
 
 def determine_type_of_array_field(ctx: FunctionContext) -> Type:
-    if 'base_field' not in ctx.callee_arg_names:
-        return ctx.default_return_type
-
-    base_field_arg_type = ctx.arg_types[ctx.callee_arg_names.index('base_field')][0]
-    if not isinstance(base_field_arg_type, Instance):
+    base_field_arg_type = helpers.get_argument_type_by_name(ctx, 'base_field')
+    if not base_field_arg_type or not isinstance(base_field_arg_type, Instance):
         return ctx.default_return_type
 
     get_method = base_field_arg_type.type.get_method('__get__')

mypy_django_plugin/plugins/models.py

@@ -2,11 +2,12 @@ from abc import ABCMeta, abstractmethod
 from typing import Dict, Iterator, Optional, Tuple, cast
 
 import dataclasses
-from mypy.nodes import AssignmentStmt, CallExpr, ClassDef, Context, Expression, Lvalue, MDEF, MemberExpr, MypyFile, NameExpr, \
-    StrExpr, SymbolTableNode, TypeInfo, Var
+from mypy.nodes import AssignmentStmt, CallExpr, ClassDef, Context, Expression, Lvalue, MDEF, MemberExpr, \
+    MypyFile, NameExpr, StrExpr, SymbolTableNode, TypeInfo, Var, Argument, ARG_STAR2
 from mypy.plugin import ClassDefContext
+from mypy.plugins.common import add_method
 from mypy.semanal import SemanticAnalyzerPass2
-from mypy.types import Instance
+from mypy.types import Instance, AnyType, TypeOfAny, NoneTyp
 
 from mypy_django_plugin import helpers
 
@@ -199,16 +200,27 @@ def extract_ref_to_fullname(rvalue_expr: CallExpr,
     return None
 
 
+def add_dummy_init_method(ctx: ClassDefContext) -> None:
+    any = AnyType(TypeOfAny.special_form)
+    var = Var('kwargs', any)
+    kw_arg = Argument(variable=var, type_annotation=any, initializer=None, kind=ARG_STAR2)
+    add_method(ctx, '__init__', [kw_arg], NoneTyp())
+    # mark as model class
+    ctx.cls.info.metadata.setdefault('django', {})['generated_init'] = True
+
+
 def process_model_class(ctx: ClassDefContext) -> None:
     initializers = [
         InjectAnyAsBaseForNestedMeta,
         AddDefaultObjectsManager,
         AddIdAttributeIfPrimaryKeyTrueIsNotSet,
         SetIdAttrsForRelatedFields,
-        AddRelatedManagers
+        AddRelatedManagers,
     ]
     for initializer_cls in initializers:
         initializer_cls.from_ctx(ctx).run()
 
+    add_dummy_init_method(ctx)
+
     # allow unspecified attributes for now
     ctx.cls.info.fallback_to_any = True

mypy_django_plugin/plugins/related_fields.py

@@ -1,20 +1,12 @@
-import typing
 from typing import Optional, cast
 
 from mypy.checker import TypeChecker
 from mypy.nodes import StrExpr, TypeInfo
 from mypy.plugin import FunctionContext
-from mypy.types import Type, CallableType, Instance, AnyType, TypeOfAny
+from mypy.types import CallableType, Instance, Type
 
 from mypy_django_plugin import helpers
-
-
-def reparametrize_with(instance: Instance, new_typevars: typing.List[Type]):
-    return Instance(instance.type, args=new_typevars)
-
-
-def fill_typevars_with_any(instance: Instance) -> Type:
-    return reparametrize_with(instance, [AnyType(TypeOfAny.unannotated)])
+from mypy_django_plugin.helpers import fill_typevars_with_any, reparametrize_with
 
 
 def get_valid_to_value_or_none(ctx: FunctionContext) -> Optional[Instance]: