Get rid of cast() & simplify Generator

rest_framework_nested/viewsets.py

@@ -1,20 +1,19 @@
 from __future__ import annotations
 
 import contextlib
-from typing import Any, Generator, Generic, TypeVar, cast
+from typing import Any, Generic, TypeVar, Iterator
 
 from django.core.exceptions import ImproperlyConfigured
 from django.db.models import Model, QuerySet
 from django.http import HttpRequest, QueryDict
-from rest_framework.generics import GenericAPIView
 from rest_framework.request import Request
-from rest_framework.viewsets import ViewSetMixin
+from rest_framework.serializers import BaseSerializer
 
 T_Model = TypeVar('T_Model', bound=Model)
 
 
 @contextlib.contextmanager
-def _force_mutable(querydict: QueryDict | dict[str, Any]) -> Generator[QueryDict | dict[str, Any], None, None]:
+def _force_mutable(querydict: QueryDict | dict[str, Any]) -> Iterator[QueryDict | dict[str, Any]]:
     """
     Takes a HttpRequest querydict from Django and forces it to be mutable.
     Reverts the initial state back on exit, if any.
@@ -39,7 +38,7 @@ def _get_parent_lookup_kwargs(self) -> dict[str, str]:
         parent_lookup_kwargs = getattr(self, 'parent_lookup_kwargs', None)
 
         if not parent_lookup_kwargs:
-            serializer_class = cast(GenericAPIView, self).get_serializer_class()
+            serializer_class: type[BaseSerializer[T_Model]] = self.get_serializer_class()  # type: ignore[attr-defined]
             parent_lookup_kwargs = getattr(serializer_class, 'parent_lookup_kwargs', None)
 
         if not parent_lookup_kwargs:
@@ -59,25 +58,25 @@ def get_queryset(self) -> QuerySet[T_Model]:
         if getattr(self, 'swagger_fake_view', False):
             return queryset
 
-        orm_filters = {}
+        orm_filters: dict[str, Any] = {}
         parent_lookup_kwargs = self._get_parent_lookup_kwargs()
         for query_param, field_name in parent_lookup_kwargs.items():
-            orm_filters[field_name] = cast(ViewSetMixin, self).kwargs[query_param]
+            orm_filters[field_name] = self.kwargs[query_param]  # type: ignore[attr-defined]
         return queryset.filter(**orm_filters)
 
     def initialize_request(self, request: HttpRequest, *args: Any, **kwargs: Any) -> Request:
         """
         Adds the parent params from URL inside the children data available
         """
-        request = cast(ViewSetMixin, super()).initialize_request(request, *args, **kwargs)
+        drf_request: Request = super().initialize_request(request, *args, **kwargs)  # type: ignore[misc]
 
         if getattr(self, 'swagger_fake_view', False):
-            return request
+            return drf_request
 
         for url_kwarg, fk_filter in self._get_parent_lookup_kwargs().items():
             # fk_filter is alike 'grandparent__parent__pk'
             parent_arg = fk_filter.partition('__')[0]
-            for querydict in [request.data, request.query_params]:
+            for querydict in [drf_request.data, drf_request.query_params]:
                 with _force_mutable(querydict):
                     querydict[parent_arg] = kwargs[url_kwarg]
-        return request
+        return drf_request