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

Backport of 02eed4f37879b2077496f86bb1378a076b981233 from main.

1 files changed, 20 insertions, 0 deletions

diff --git a/tests/composite_pk/test_aggregate.py b/tests/composite_pk/test_aggregate.py
index d852fdce30..8a2067cb90 100644
--- a/tests/composite_pk/test_aggregate.py
+++ b/tests/composite_pk/test_aggregate.py
@@ -141,3 +141,23 @@ class CompositePKAggregateTests(TestCase):
         msg = "Max expression does not support composite primary keys."
         with self.assertRaisesMessage(ValueError, msg):
             Comment.objects.aggregate(Max("pk"))
+
+    def test_first_from_unordered_queryset_aggregation_pk_selected(self):
+        self.assertEqual(
+            Comment.objects.values("pk").annotate(max=Max("id")).first(),
+            {"pk": (1, 1), "max": 1},
+        )
+
+    def test_first_from_unordered_queryset_aggregation_pk_selected_separately(self):
+        self.assertEqual(
+            Comment.objects.values("tenant", "id").annotate(max=Max("id")).first(),
+            {"tenant": 1, "id": 1, "max": 1},
+        )
+
+    def test_first_from_unordered_queryset_aggregation_pk_incomplete(self):
+        msg = (
+            "Cannot use QuerySet.first() on an unordered queryset performing "
+            "aggregation. Add an ordering with order_by()."
+        )
+        with self.assertRaisesMessage(TypeError, msg):
+            Comment.objects.values("tenant").annotate(max=Max("id")).first()