Improve typing of view decorators

django-stubs/views/decorators/__init__.pyi

@@ -0,0 +1,13 @@
+from typing import Any, Protocol, TypeVar
+
+from django.http.request import HttpRequest
+from django.http.response import HttpResponseBase
+
+# `*args: Any, **kwargs: Any` means any extra argument(s) can be provided, or none.
+class _View(Protocol):
+    def __call__(self, request: HttpRequest, /, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+
+class _AsyncView(Protocol):
+    async def __call__(self, request: HttpRequest, /, *args: Any, **kwargs: Any) -> HttpResponseBase: ...
+
+_ViewFuncT = TypeVar("_ViewFuncT", bound=_View | _AsyncView)  # noqa: PYI018

django-stubs/views/decorators/cache.pyi

@@ -1,10 +1,10 @@
 from collections.abc import Callable
-from typing import Any, TypeVar
+from typing import Any
 
-_F = TypeVar("_F", bound=Callable[..., Any])
+from . import _ViewFuncT
 
 def cache_page(
-    timeout: float | None, *, cache: Any | None = ..., key_prefix: Any | None = ...
-) -> Callable[[_F], _F]: ...
-def cache_control(**kwargs: Any) -> Callable[[_F], _F]: ...
-def never_cache(view_func: _F) -> _F: ...
+    timeout: float | None, *, cache: Any | None = ..., key_prefix: str | None = ...
+) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def cache_control(**kwargs: Any) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def never_cache(view_func: _ViewFuncT, /) -> _ViewFuncT: ...

django-stubs/views/decorators/clickjacking.pyi

@@ -1,8 +1,5 @@
-from collections.abc import Callable
-from typing import Any, TypeVar
+from . import _ViewFuncT
 
-_F = TypeVar("_F", bound=Callable[..., Any])
-
-def xframe_options_deny(view_func: _F) -> _F: ...
-def xframe_options_sameorigin(view_func: _F) -> _F: ...
-def xframe_options_exempt(view_func: _F) -> _F: ...
+def xframe_options_deny(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
+def xframe_options_sameorigin(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
+def xframe_options_exempt(view_func: _ViewFuncT, /) -> _ViewFuncT: ...

django-stubs/views/decorators/common.pyi

@@ -1,6 +1,3 @@
-from collections.abc import Callable
-from typing import Any, TypeVar
+from . import _ViewFuncT
 
-_C = TypeVar("_C", bound=Callable[..., Any])
-
-def no_append_slash(view_func: _C) -> _C: ...
+def no_append_slash(view_func: _ViewFuncT, /) -> _ViewFuncT: ...

django-stubs/views/decorators/csrf.pyi

@@ -1,18 +1,14 @@
-from collections.abc import Callable
-from typing import Any, TypeVar
-
 from django.middleware.csrf import CsrfViewMiddleware
 
-csrf_protect: Callable[[_F], _F]
+from . import _ViewFuncT
+
+def csrf_protect(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
 
 class _EnsureCsrfToken(CsrfViewMiddleware): ...
 
-requires_csrf_token: Callable[[_F], _F]
+def requires_csrf_token(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
 
 class _EnsureCsrfCookie(CsrfViewMiddleware): ...
 
-ensure_csrf_cookie: Callable[[_F], _F]
-
-_F = TypeVar("_F", bound=Callable[..., Any])
-
-def csrf_exempt(view_func: _F) -> _F: ...
+def ensure_csrf_cookie(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
+def csrf_exempt(view_func: _ViewFuncT, /) -> _ViewFuncT: ...

django-stubs/views/decorators/gzip.pyi

@@ -1,6 +1,3 @@
-from collections.abc import Callable
-from typing import Any, TypeVar
+from . import _ViewFuncT
 
-_C = TypeVar("_C", bound=Callable[..., Any])
-
-gzip_page: Callable[[_C], _C]
+def gzip_page(view_func: _ViewFuncT, /) -> _ViewFuncT: ...

django-stubs/views/decorators/http.pyi

@@ -1,19 +1,15 @@
 from collections.abc import Callable, Container
 from datetime import datetime
-from typing import Any, TypeVar
 
-_F = TypeVar("_F", bound=Callable[..., Any])
-
-conditional_page: Callable[[_F], _F]
-
-def require_http_methods(request_method_list: Container[str]) -> Callable[[_F], _F]: ...
-
-require_GET: Callable[[_F], _F]
-require_POST: Callable[[_F], _F]
-require_safe: Callable[[_F], _F]
+from . import _ViewFuncT
 
+def conditional_page(view_func: _ViewFuncT, /) -> _ViewFuncT: ...
+def require_http_methods(request_method_list: Container[str]) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def require_GET(func: _ViewFuncT, /) -> _ViewFuncT: ...
+def require_POST(func: _ViewFuncT, /) -> _ViewFuncT: ...
+def require_safe(func: _ViewFuncT, /) -> _ViewFuncT: ...
 def condition(
     etag_func: Callable[..., str | None] | None = ..., last_modified_func: Callable[..., datetime | None] | None = ...
-) -> Callable[[_F], _F]: ...
-def etag(etag_func: Callable[..., str | None]) -> Callable[[_F], _F]: ...
-def last_modified(last_modified_func: Callable[..., datetime | None]) -> Callable[[_F], _F]: ...
+) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def etag(etag_func: Callable[..., str | None]) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def last_modified(last_modified_func: Callable[..., datetime | None]) -> Callable[[_ViewFuncT], _ViewFuncT]: ...

django-stubs/views/decorators/vary.pyi

@@ -1,7 +1,6 @@
 from collections.abc import Callable
-from typing import Any, TypeVar
 
-_F = TypeVar("_F", bound=Callable[..., Any])
+from . import _ViewFuncT
 
-def vary_on_headers(*headers: str) -> Callable[[_F], _F]: ...
-def vary_on_cookie(func: _F) -> _F: ...
+def vary_on_headers(*headers: str) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
+def vary_on_cookie(func: _ViewFuncT, /) -> _ViewFuncT: ...

tests/assert_type/views/decorators/test_csrf.py

@@ -0,0 +1,46 @@
+from typing import Callable
+
+from django.http.request import HttpRequest
+from django.http.response import HttpResponse
+from django.views.decorators.csrf import csrf_protect
+from typing_extensions import assert_type
+
+
+@csrf_protect
+def good_view_positional(request: HttpRequest, /) -> HttpResponse:
+    return HttpResponse()
+
+
+# `assert_type` can only be used when `request` is pos. only.
+assert_type(good_view_positional, Callable[[HttpRequest], HttpResponse])
+
+
+# The decorator works too if `request` is not explicitly pos. only.
+@csrf_protect
+def good_view(request: HttpRequest) -> HttpResponse:
+    return HttpResponse()
+
+
+@csrf_protect
+async def good_async_view(request: HttpRequest) -> HttpResponse:
+    return HttpResponse()
+
+
+@csrf_protect
+def good_view_with_arguments(request: HttpRequest, other: int, args: str) -> HttpResponse:
+    return HttpResponse()
+
+
+@csrf_protect
+async def good_async_view_with_arguments(request: HttpRequest, other: int, args: str) -> HttpResponse:
+    return HttpResponse()
+
+
+@csrf_protect  # type: ignore[type-var]  # pyright: ignore[reportArgumentType, reportUntypedFunctionDecorator]
+def bad_view(request: int) -> str:
+    return ""
+
+
+@csrf_protect  # type: ignore[type-var]  # pyright: ignore[reportArgumentType, reportUntypedFunctionDecorator]
+def bad_view_no_arguments() -> HttpResponse:
+    return HttpResponse()