Ensure multiple admin get methods returns either list or tuple (#1833)

The get methods serves as extension points for corresponding attributes
on the admin class. Thus we align the return type of the the methods
with their corresponding attribute's type.

Author: flaeppe

django-stubs/contrib/admin/options.pyi

@@ -74,6 +74,7 @@ _ListFilterT: TypeAlias = (
 # Generic type specifically for models, for use in BaseModelAdmin and subclasses
 # https://github.com/typeddjango/django-stubs/issues/482
 _ModelT = TypeVar("_ModelT", bound=Model)
+_DisplayT: TypeAlias = _ListOrTuple[str | Callable[[_ModelT], str | bool]]
 
 class BaseModelAdmin(Generic[_ModelT]):
     autocomplete_fields: _ListOrTuple[str]
@@ -87,7 +88,7 @@ class BaseModelAdmin(Generic[_ModelT]):
     radio_fields: Mapping[str, _Direction]
     prepopulated_fields: dict[str, Sequence[str]]
     formfield_overrides: Mapping[type[Field], Mapping[str, Any]]
-    readonly_fields: _ListOrTuple[str] | None
+    readonly_fields: _ListOrTuple[str]
     ordering: _ListOrTuple[str] | None
     sortable_by: _ListOrTuple[str] | None
     view_on_site: bool | Callable[[_ModelT], str]
@@ -107,18 +108,18 @@ class BaseModelAdmin(Generic[_ModelT]):
     def formfield_for_manytomany(
         self, db_field: ManyToManyField, request: HttpRequest, **kwargs: Any
     ) -> ModelMultipleChoiceField | None: ...
-    def get_autocomplete_fields(self, request: HttpRequest) -> Sequence[str]: ...
+    def get_autocomplete_fields(self, request: HttpRequest) -> _ListOrTuple[str]: ...
     def get_view_on_site_url(self, obj: _ModelT | None = ...) -> str | None: ...
     def get_empty_value_display(self) -> SafeString: ...
-    def get_exclude(self, request: HttpRequest, obj: _ModelT | None = ...) -> Sequence[str] | None: ...
+    def get_exclude(self, request: HttpRequest, obj: _ModelT | None = ...) -> _ListOrTuple[str] | None: ...
     def get_fields(self, request: HttpRequest, obj: _ModelT | None = ...) -> _FieldGroups: ...
     def get_fieldsets(self, request: HttpRequest, obj: _ModelT | None = ...) -> _FieldsetSpec: ...
     def get_inlines(self, request: HttpRequest, obj: _ModelT | None) -> list[type[InlineModelAdmin]]: ...
-    def get_ordering(self, request: HttpRequest) -> Sequence[str]: ...
-    def get_readonly_fields(self, request: HttpRequest, obj: _ModelT | None = ...) -> Sequence[str]: ...
+    def get_ordering(self, request: HttpRequest) -> _ListOrTuple[str]: ...
+    def get_readonly_fields(self, request: HttpRequest, obj: _ModelT | None = ...) -> _ListOrTuple[str]: ...
     def get_prepopulated_fields(self, request: HttpRequest, obj: _ModelT | None = ...) -> dict[str, Sequence[str]]: ...
     def get_queryset(self, request: HttpRequest) -> QuerySet[_ModelT]: ...
-    def get_sortable_by(self, request: HttpRequest) -> Sequence[str]: ...
+    def get_sortable_by(self, request: HttpRequest) -> _DisplayT: ...
     def lookup_allowed(self, lookup: str, value: str) -> bool: ...
     def to_field_allowed(self, request: HttpRequest, to_field: str) -> bool: ...
     def has_add_permission(self, request: HttpRequest) -> bool: ...
@@ -128,7 +129,6 @@ class BaseModelAdmin(Generic[_ModelT]):
     def has_view_or_change_permission(self, request: HttpRequest, obj: _ModelT | None = ...) -> bool: ...
     def has_module_permission(self, request: HttpRequest) -> bool: ...
 
-_DisplayT: TypeAlias = _ListOrTuple[str | Callable[[_ModelT], str | bool]]
 _ModelAdmin = TypeVar("_ModelAdmin", bound=ModelAdmin)
 _ActionCallable: TypeAlias = Callable[[_ModelAdmin, HttpRequest, QuerySet[_ModelT]], HttpResponseBase | None]
 
@@ -202,9 +202,9 @@ class ModelAdmin(BaseModelAdmin[_ModelT]):
     def get_action(self, action: Callable | str) -> tuple[Callable[..., str], str, str] | None: ...
     def get_list_display(self, request: HttpRequest) -> _DisplayT: ...
     def get_list_display_links(self, request: HttpRequest, list_display: _DisplayT) -> _DisplayT: ...
-    def get_list_filter(self, request: HttpRequest) -> Sequence[_ListFilterT]: ...
-    def get_list_select_related(self, request: HttpRequest) -> bool | Sequence[str]: ...
-    def get_search_fields(self, request: HttpRequest) -> Sequence[str]: ...
+    def get_list_filter(self, request: HttpRequest) -> _ListOrTuple[_ListFilterT]: ...
+    def get_list_select_related(self, request: HttpRequest) -> bool | _ListOrTuple[str]: ...
+    def get_search_fields(self, request: HttpRequest) -> _ListOrTuple[str]: ...
     def get_search_results(
         self, request: HttpRequest, queryset: QuerySet, search_term: str
     ) -> tuple[QuerySet[_ModelT], bool]: ...