Self used in contravariant positions

[jorenham]

In e.g. django.db.models.Model.[a]refresh_from_db, Self is used in a contravariant position:

django-stubs/django-stubs/db/models/base.pyi

Lines 96 to 107 in 0be73eb

	def refresh_from_db(
	self,
	using: str | None = None,
	fields: Iterable[str] | None = None,
	from_queryset: QuerySet[Self] | None = None,
	) -> None: ...
	async def arefresh_from_db(
	self,
	using: str | None = None,
	fields: Iterable[str] | None = None,
	from_queryset: QuerySet[Self] | None = None,
	) -> None: ...

When I override this in my own model as e.g.

    @override
    def refresh_from_db(
        self,
        using: str | None = None,
        fields: Iterable[str] | None = None,
        from_queryset: QuerySet[Self] | None = None,
    ) -> None:

it violates the LSP, as explained in https://discuss.python.org/t/unsoundness-of-contravariant-self-type/86338. On pyright>=1.1.399, it will reportIncompatibleMethodOverride.

The workaround is to instead use QuerySet[Any] in the code above.

Perhaps a self: T with QuerySet[T] could work here? I'm not sure whether that'd make it theoretically sound, but it might be worth a shot 🤷🏻.

System information

• OS: irrelevant
• python version: 3.13
• django version: 5.2
• mypy version: pyright==1.1.399 or basedpyright==1.28.5
• django-stubs version: 5.1.3
• django-stubs-ext version: 5.1.3

[sobolevn]

PR is welcome! Thanks for noticing!