Calling queryset.in_bulk() after queryset.values() or queryset.values_list() results in unhelpful error

[john-parton]

Calling

MyModel.objects.values().in_bulk()

Results in a rather annoying error message that doesn't help the user.

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/john/Code/ecom/.venv/lib/python3.12/site-packages/django/db/models/query.py", line 1156, in in_bulk
    return {getattr(obj, field_name): obj for obj in qs}
            ^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'dict' object has no attribute 'pk'

This is because the in_bulk method assumes that the queryset has the default _iterable_class (ModelIterable) and is attempting to access a property on an object, but the _iterable_class returns dictionaries.

The correct behavior should be either to:

1. Raise a more helpful error if the user attempts to call in_bulk() where the _iterable_class isn't the standard ModelIterable; or
2. Define behavior for when in_bulk() is called in that case. (I think that might be rather challenging, so Behavior 1 is probably the better option.)

[john-parton]

Pull request here ​https://github.com/django/django/pull/18496

[john-parton]

I've created a second more complicated pull request that implements some reasonable behavior: ​https://github.com/django/django/pull/18497

[Sarah Boyce]

Raising a more helpful error sounds good to me

[Sarah Boyce]

Note that this has similarities to #26565
​PR

[Sarah Boyce <42296566+sarahboyce@…>]

In e4a2e22:

Fixed #35690 -- Errored nicely when using in_bulk() with a values() or values_list() queryset.