Allow any function for admin's display and action decorators (#2210)

I realised that:
- The `display` decorator isn't limited to any specific type of
  callable, it accepts anything really.
- The `action` decorator was trying to dictate a callable type that the
  `ModelAdmin.actions` expects. But that's the responsibility of
  `ModelAdmin`.

django-stubs/contrib/admin/decorators.pyi

@@ -3,53 +3,41 @@ from typing import Any, TypeVar, overload
 
 from django.contrib.admin import ModelAdmin
 from django.contrib.admin.sites import AdminSite
-from django.db.models import QuerySet
 from django.db.models.base import Model
 from django.db.models.expressions import BaseExpression, Combinable
-from django.http import HttpRequest, HttpResponseBase
 from django.utils.functional import _StrOrPromise
-from typing_extensions import TypeAlias
 
-_Model = TypeVar("_Model", bound=Model)
-_ModelAdmin = TypeVar("_ModelAdmin", bound=ModelAdmin)
-_Request = TypeVar("_Request", bound=HttpRequest)
-_QuerySet = TypeVar("_QuerySet", bound=QuerySet)
-# This is deliberately different from _DisplayT defined in contrib.admin.options
-_DisplayCallable: TypeAlias = Callable[[_ModelAdmin, _Model], Any] | Callable[[_Model], Any]
-_DisplayCallableT = TypeVar("_DisplayCallableT", bound=_DisplayCallable)
-_ActionReturn = TypeVar("_ActionReturn", bound=HttpResponseBase | None)
+_ModelAdmin = TypeVar("_ModelAdmin", bound=ModelAdmin[Any])
+_F = TypeVar("_F", bound=Callable[..., Any])
 
 @overload
 def action(
-    function: Callable[[_ModelAdmin, _Request, _QuerySet], _ActionReturn],
+    function: _F,
     permissions: Sequence[str] | None = ...,
     description: _StrOrPromise | None = ...,
-) -> Callable[[_ModelAdmin, _Request, _QuerySet], _ActionReturn]: ...
+) -> _F: ...
 @overload
 def action(
     *,
     permissions: Sequence[str] | None = ...,
     description: _StrOrPromise | None = ...,
-) -> Callable[
-    [Callable[[_ModelAdmin, _Request, _QuerySet], _ActionReturn]],
-    Callable[[_ModelAdmin, _Request, _QuerySet], _ActionReturn],
-]: ...
+) -> Callable[[_F], _F]: ...
 @overload
 def display(
-    function: _DisplayCallableT,
+    function: _F,
     boolean: bool | None = ...,
     ordering: str | Combinable | BaseExpression | None = ...,
     description: _StrOrPromise | None = ...,
     empty_value: str | None = ...,
-) -> _DisplayCallableT: ...
+) -> _F: ...
 @overload
 def display(
     *,
     boolean: bool | None = ...,
     ordering: str | Combinable | BaseExpression | None = ...,
     description: _StrOrPromise | None = ...,
     empty_value: str | None = ...,
-) -> Callable[[_DisplayCallableT], _DisplayCallableT]: ...
+) -> Callable[[_F], _F]: ...
 def register(
     *models: type[Model], site: AdminSite | None = ...
 ) -> Callable[[type[_ModelAdmin]], type[_ModelAdmin]]: ...

django-stubs/contrib/admin/options.pyi

@@ -34,7 +34,7 @@ from django.urls.resolvers import URLPattern
 from django.utils.datastructures import _ListOrTuple
 from django.utils.functional import _StrOrPromise
 from django.utils.safestring import SafeString
-from typing_extensions import TypeAlias, TypedDict
+from typing_extensions import Self, TypeAlias, TypedDict
 
 IS_POPUP_VAR: str
 TO_FIELD_VAR: str
@@ -139,7 +139,7 @@ class BaseModelAdmin(Generic[_ModelT]):
     @property
     def view_on_site(self) -> Callable[[_ModelT], str] | bool: ...
 
-_ModelAdmin = TypeVar("_ModelAdmin", bound=ModelAdmin)
+_ModelAdmin = TypeVar("_ModelAdmin", bound=ModelAdmin[Any])
 _ActionCallable: TypeAlias = Callable[[_ModelAdmin, HttpRequest, QuerySet[_ModelT]], HttpResponseBase | None]
 
 class ModelAdmin(BaseModelAdmin[_ModelT]):
@@ -167,7 +167,7 @@ class ModelAdmin(BaseModelAdmin[_ModelT]):
     delete_selected_confirmation_template: _TemplateForResponseT | None
     object_history_template: _TemplateForResponseT | None
     popup_response_template: _TemplateForResponseT | None
-    actions: Sequence[_ActionCallable[Any, _ModelT] | str] | None
+    actions: Sequence[_ActionCallable[Self, _ModelT] | str] | None
     action_form: Any
     actions_on_top: bool
     actions_on_bottom: bool

tests/typecheck/contrib/admin/test_decorators.yml

@@ -79,12 +79,6 @@
     @admin.action
     def freestanding_action_file_response(modeladmin: "MyModelAdmin", request: HttpRequest, queryset: QuerySet[MyModel]) -> FileResponse: ...
 
-    @admin.action # E: Value of type variable "_ModelAdmin" of "action" cannot be "int"  [type-var]
-    def freestanding_action_invalid_bare(modeladmin: int, request: HttpRequest, queryset: QuerySet[MyModel]) -> None: ...
-
-    @admin.action(description="Some text here", permissions=["test"]) # E: Value of type variable "_ModelAdmin" of function cannot be "int"  [type-var]
-    def freestanding_action_invalid_fancy(modeladmin: int, request: HttpRequest, queryset: QuerySet[MyModel]) -> None: ...
-
     @admin.register(MyModel)
     class MyModelAdmin(admin.ModelAdmin[MyModel]):
         actions = [freestanding_action_bare, freestanding_action_fancy, "method_action_bare", "method_action_fancy", freestanding_action_http_response, freestanding_action_file_response]
@@ -101,14 +95,8 @@
         @admin.action(description="Some text here", permissions=["test"])
         def method_action_file_response(self, request: HttpRequest, queryset: QuerySet[MyModel]) -> FileResponse: ...
 
-        @admin.action  # E: Value of type variable "_QuerySet" of "action" cannot be "int"  [type-var]
-        def method_action_invalid_bare(self, request: HttpRequest, queryset: int) -> None: ...
-
-        @admin.action(description="Some text here", permissions=["test"])  # E: Value of type variable "_QuerySet" of function cannot be "int"  [type-var]
-        def method_action_invalid_fancy(self, request: HttpRequest, queryset: int) -> None: ...
-
         def method(self) -> None:
-            reveal_type(self.method_action_bare)  # N: Revealed type is "def (django.http.request.HttpRequest, django.db.models.query.QuerySet[main.MyModel, main.MyModel])"
-            reveal_type(self.method_action_fancy)  # N: Revealed type is "def (django.http.request.HttpRequest, django.db.models.query.QuerySet[main.MyModel, main.MyModel])"
-            reveal_type(self.method_action_http_response)  # N: Revealed type is "def (django.http.request.HttpRequest, django.db.models.query.QuerySet[main.MyModel, main.MyModel]) -> django.http.response.HttpResponse"
-            reveal_type(self.method_action_file_response)  # N: Revealed type is "def (django.http.request.HttpRequest, django.db.models.query.QuerySet[main.MyModel, main.MyModel]) -> django.http.response.FileResponse"
+            reveal_type(self.method_action_bare)  # N: Revealed type is "def (request: django.http.request.HttpRequest, queryset: django.db.models.query.QuerySet[main.MyModel, main.MyModel])"
+            reveal_type(self.method_action_fancy)  # N: Revealed type is "def (request: django.http.request.HttpRequest, queryset: django.db.models.query.QuerySet[main.MyModel, main.MyModel])"
+            reveal_type(self.method_action_http_response)  # N: Revealed type is "def (request: django.http.request.HttpRequest, queryset: django.db.models.query.QuerySet[main.MyModel, main.MyModel]) -> django.http.response.HttpResponse"
+            reveal_type(self.method_action_file_response)  # N: Revealed type is "def (request: django.http.request.HttpRequest, queryset: django.db.models.query.QuerySet[main.MyModel, main.MyModel]) -> django.http.response.FileResponse"

tests/typecheck/contrib/admin/test_options.yml

@@ -141,13 +141,15 @@
     main: |
       from django.contrib import admin
       from django.http.request import HttpRequest
-      from django.db.models.query import QuerySet
+      from django.db import models
+
+      class MyModel(models.Model): ...
 
       def an_action(modeladmin: None) -> None:
           pass
 
-      class A(admin.ModelAdmin):
-          actions = [an_action]  # E: List item 0 has incompatible type "Callable[[None], None]"; expected "Union[Callable[[Any, HttpRequest, QuerySet[Any, Any]], Optional[HttpResponseBase]], str]"  [list-item]
+      class A(admin.ModelAdmin[MyModel]):
+          actions = [an_action]  # E: List item 0 has incompatible type "Callable[[None], None]"; expected "Union[Callable[[A, HttpRequest, QuerySet[MyModel, MyModel]], Optional[HttpResponseBase]], str]"  [list-item]
 -   case: errors_for_invalid_model_admin_generic
     main: |
       from django.contrib.admin import ModelAdmin