From 28c95a35fbf1a64bb342f622a90fbaaf46315819 Mon Sep 17 00:00:00 2001
From: Jacob Walls <jacobtylerwalls@gmail.com>
Date: Mon, 13 Oct 2025 17:22:17 -0400
Subject: [PATCH] [6.0.x] Fixed #36648, Refs #33772 -- Accounted for composite
 pks in first()/last() when aggregating.

Backport of 02eed4f37879b2077496f86bb1378a076b981233 from main.
---
 django/db/models/query.py            | 10 ++++++++--
 docs/releases/5.2.8.txt              |  4 ++++
 tests/composite_pk/test_aggregate.py | 20 ++++++++++++++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/django/db/models/query.py b/django/db/models/query.py
index 721bf33e57..7ff28b74e0 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -2077,8 +2077,14 @@ class QuerySet(AltersData):
             raise TypeError(f"Cannot use {operator_} operator with combined queryset.")
 
     def _check_ordering_first_last_queryset_aggregation(self, method):
-        if isinstance(self.query.group_by, tuple) and not any(
-            col.output_field is self.model._meta.pk for col in self.query.group_by
+        if (
+            isinstance(self.query.group_by, tuple)
+            # Raise if the pk fields are not in the group_by.
+            and self.model._meta.pk
+            not in {col.output_field for col in self.query.group_by}
+            and set(self.model._meta.pk_fields).difference(
+                {col.target for col in self.query.group_by}
+            )
         ):
             raise TypeError(
                 f"Cannot use QuerySet.{method}() on an unordered queryset performing "
diff --git a/docs/releases/5.2.8.txt b/docs/releases/5.2.8.txt
index ef18d08022..dc750e4636 100644
--- a/docs/releases/5.2.8.txt
+++ b/docs/releases/5.2.8.txt
@@ -10,3 +10,7 @@ Bugfixes
 ========
 
 * Added compatibility for ``oracledb`` 3.4.0 (:ticket:`36646`).
+
+* Fixed a bug in Django 5.2 where ``QuerySet.first()`` and ``QuerySet.last()``
+  raised an error on querysets performing aggregation that selected all fields
+  of a composite primary key.
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()