"pk" exception when using first() on unordered queryset with aggregation does not consider composite pk fields provided separately

[Jacob Walls]

Discovered while poking into the source for first() that we have a special case for "pk" that does not behave equivalently for composite primary key fields specified individually.

A test for CompositePKAggregateTests:

The commented out assertion shows the point of the guard -- it should raise a TypeError in most cases of using first() on an unordered queryset, see #33772.

The second assertion shows the exception for values("pk") -- this does not raise.
The third assertion tries to provide the values for a composite pk separately -- this should not raise...

    def test_group_by_guard(self):
        # This assertion passes, only included to demonstrate the behavior.
        # with self.assertRaises(TypeError):
        #     Comment.objects.values("text").annotate(max=Max("id")).first()
        Comment.objects.values("pk").annotate(max=Max("id")).first()  # passes
        Comment.objects.values("tenant", "id").annotate(max=Max("id")).first()  # fails

... but does:

TypeError: Cannot use QuerySet.first() on an unordered queryset performing aggregation. Add an ordering with order_by().

[Jacob Walls]

​PR

[Jacob Walls <jacobtylerwalls@…>]

In 02eed4f:

Fixed #36648, Refs #33772 -- Accounted for composite pks in first()/last() when aggregating.

[Jacob Walls <jacobtylerwalls@…>]

In 28c95a35:

[6.0.x] Fixed #36648, Refs #33772 -- Accounted for composite pks in first()/last() when aggregating.

Backport of 02eed4f37879b2077496f86bb1378a076b981233 from main.

[Jacob Walls <jacobtylerwalls@…>]

In 8baee53:

[5.2.x] Fixed #36648, Refs #33772 -- Accounted for composite pks in first()/last() when aggregating.

Backport of 02eed4f37879b2077496f86bb1378a076b981233 from main.

[Jacob Walls <jacobtylerwalls@…>]

In bee6456:

Refs #36648 -- Removed hardcoded pk in CompositePKAggregateTests.

[Jacob Walls <jacobtylerwalls@…>]

In 2cc9072:

[6.0.x] Refs #36648 -- Removed hardcoded pk in CompositePKAggregateTests.

Backport of bee64561a6e8cd22995c2b1254bab66dae892a6d from main.

[Jacob Walls <jacobtylerwalls@…>]

In dc61f20:

[5.2.x] Refs #36648 -- Removed hardcoded pk in CompositePKAggregateTests.

Backport of bee64561a6e8cd22995c2b1254bab66dae892a6d from main.