QuerySet implements `contains` but not `__contains__`

[fidoriel]

This is a similar proposal to #31561, but it is not the same. Currently using x in myQuerySet results in Python using the fallback solution: ​https://docs.python.org/3/reference/expressions.html#membership-test-details because ​https://groups.google.com/g/django-developers/c/NZaMq9BALrs/m/OCNTh6QyCAAJ decided to implement contains in #24141.

I think it is only consistent to have the same behavior implemented in __contains__. I would expect that, it is also a more efficient implementation and unifies Django behavior. Nevertheless, documentation is needed why this inconsistency exists. I was not able to find a reason. Because the mailing list agreed on adding contains, this is discussed behavior. Why was __contains__ not added in the first place? To not have breaking changes? I cannot see what would break.

As said in #31561 a queryset could be a collection to make typing easier. But this is not the intention of this issue.

[Mariusz Felisiak]

Why was __contains__ not added in the first place?

Have you read the discussion that you mention in the ticket? or comments in #24141? The entire discussion is about __contains__ and there was a consensus to add contains() instead.