`GenericPrefetch` should have `queryset` parameter as required

[Sobolev Nikita]

Original issue: https://code.djangoproject.com/ticket/33651

Source: ​https://github.com/django/django/blob/91a4b9a8ec2237434f06866f39c7977e889aeae6/django/contrib/contenttypes/prefetch.py#L6-L7

Right now this code is really strange. It produces this result:

>>> import django
>>> from django.contrib.contenttypes.prefetch import GenericPrefetch
>>> GenericPrefetch('a')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/sobolev/Documents/github/wemake-django-template/.venv/lib/python3.11/site-packages/django/contrib/contenttypes/prefetch.py", line 7, in __init__
    for queryset in querysets:
TypeError: 'NoneType' object is not iterable

I guess that there are two ways:

• Using if querysets is None: querysets = []
• Requiring this argument, which I guess is the correct thing to do. Why would we ever want this field to be empty?

I will send a PR with the fix.

I found this while working on ​https://github.com/typeddjango/django-stubs/pull/2115

[Sarah Boyce]

Hi Sobelev, thank you for the report and patch!
Agreed this is a bug in cac94dd8aa2fb49cd2e06b5b37cf039257284bb0, as this is a new feature introduced in 5.0, marking as a release blocker.

[Sarah Boyce <42296566+sarahboyce@…>]

In 9a27c760:

Fixed #35426 -- Updated querysets to be a required argument of GenericPrefetch.

[Sarah Boyce <42296566+sarahboyce@…>]

In 9b5029f0:

[5.0.x] Fixed #35426 -- Updated querysets to be a required argument of GenericPrefetch.

Backport of 9a27c76021f934201cccf12215514a3091325ec8 from main.