Allow Views to return the more generic HttpResponseBase instead of HttpResponse, to allow returning StreamingHttpResponse (#607)

* Add type hints for the postgres CursorDebugWrapper, expand the BaseCursorDebugWrapper.

* Fix how Optinal gets applied.

* Fix optional handling further.

* Adjust postgres debugcursorwrapper to look more like the implementation.

* Apply review feedback.

* Use the more generic HttpResponseBase when appriopriate.

* Fix failing test and add new test.

* Remove the other test again, it was the wrong location. Add new tests in the correct location.

Co-authored-by: LanDinh <coding+sourcetree@khaleesi.ninja>

django-stubs/views/generic/base.pyi

@@ -1,6 +1,7 @@
 from typing import Any, Callable, Dict, List, Optional, Type
 
 from django import http
+from django.http.response import HttpResponseBase
 
 class ContextMixin:
     def get_context_data(self, **kwargs: Any) -> Dict[str, Any]: ...
@@ -12,9 +13,9 @@ class View:
     kwargs: Any = ...
     def __init__(self, **kwargs: Any) -> None: ...
     @classmethod
-    def as_view(cls: Any, **initkwargs: Any) -> Callable[..., http.HttpResponse]: ...
+    def as_view(cls: Any, **initkwargs: Any) -> Callable[..., HttpResponseBase]: ...
     def setup(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> None: ...
-    def dispatch(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
+    def dispatch(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
     def http_method_not_allowed(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
     def options(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
 
@@ -36,9 +37,9 @@ class RedirectView(View):
     pattern_name: Optional[str] = ...
     query_string: bool = ...
     def get_redirect_url(self, *args: Any, **kwargs: Any) -> Optional[str]: ...
-    def get(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
-    def head(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
-    def post(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
-    def delete(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
-    def put(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
-    def patch(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> http.HttpResponse: ...
+    def get(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+    def head(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+    def post(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+    def delete(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+    def put(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+    def patch(self, request: http.HttpRequest, *args: Any, **kwargs: Any) -> HttpResponseBase: ...

tests/typecheck/utils/test_decorators.yml

@@ -11,10 +11,10 @@
       from django.views.generic.base import View
       from django.utils.decorators import method_decorator
       from django.contrib.auth.decorators import login_required
-      from django.http.response import HttpResponse
+      from django.http.response import HttpResponseBase
       from django.http.request import HttpRequest
       class TestView(View):
           @method_decorator(login_required)
-          def dispatch(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
+          def dispatch(self, request: HttpRequest, *args, **kwargs) -> HttpResponseBase:
               return super().dispatch(request, *args, **kwargs)
-          reveal_type(dispatch)  # N: Revealed type is 'def (self: main.TestView, request: django.http.request.HttpRequest, *args: Any, **kwargs: Any) -> django.http.response.HttpResponse'
+          reveal_type(dispatch)  # N: Revealed type is 'def (self: main.TestView, request: django.http.request.HttpRequest, *args: Any, **kwargs: Any) -> django.http.response.HttpResponseBase'

tests/typecheck/views/generic/test_edit.yml

@@ -10,3 +10,21 @@
                 """Ensure that form can have type AuthenticationForm."""
                 form.get_user()
                 return HttpResponseRedirect(self.get_success_url())
+-   case: dispatch_http_response
+    main: |
+        from django.http import HttpResponse
+        from django.views.generic.base import View
+
+        class MyView(View):
+            def dispatch(self, request, *args, **kwargs) -> HttpResponse:
+                response: HttpResponse
+                return response
+-   case: dispatch_streaming_http_response
+    main: |
+        from django.http import StreamingHttpResponse
+        from django.views.generic.base import View
+
+        class MyView(View):
+            def dispatch(self, request, *args, **kwargs) -> StreamingHttpResponse:
+                response: StreamingHttpResponse
+                return response