Expect a QuerySet for multiple defaults in MultipleObjectMixin

[flaeppe]

When MultipleObjectMixin adds a more specific type than "something that can be sliced" (i.e. _SupportsPagination) for default types of queryset attributes/arguments a couple of subclass views gets a better default behaviour.

The changes here go under the same argument as in #2174 (comment)

Related issues

• Closes ListView.get_queryset() cannot be treated as a queryset #1928
• Refs Formset get_queryset() returns QuerySet #2174

[flaeppe]

@sobolevn and @intgr does any of you want to check this out?

[sobolevn]

I think that the main reason for a protocol is that it can also paginate lists, tuples, etc:

django-stubs/django-stubs/core/paginator.pyi

Lines 14 to 19 in 590f033

	@type_check_only
	class _SupportsPagination(Protocol[_T], Sized, Iterable):
	@overload
	def __getitem__(self, index: int, /) -> _T: ...
	@overload
	def __getitem__(self, index: slice, /) -> _SupportsPagination[_T]: ...

But, anyway

[flaeppe]

Yes, definitely. But it conflicts with having access to builtin queryset methods e.g. .filter