Fixed #34013 -- Added QuerySet.order_by() support for annotation transforms.

Thanks Eugene Morozov and Ben Nace for the reports.

tests/aggregation/tests.py

@@ -25,6 +25,7 @@ from django.db.models import (
     Subquery,
     Sum,
     TimeField,
+    Transform,
     Value,
     Variance,
     When,
@@ -1727,6 +1728,28 @@ class AggregateTestCase(TestCase):
             ordered=False,
         )
 
+    def test_order_by_aggregate_transform(self):
+        class Mod100(Mod, Transform):
+            def __init__(self, expr):
+                super().__init__(expr, 100)
+
+        sum_field = IntegerField()
+        sum_field.register_instance_lookup(Mod100, "mod100")
+        publisher_pages = (
+            Book.objects.values("publisher")
+            .annotate(sum_pages=Sum("pages", output_field=sum_field))
+            .order_by("sum_pages__mod100")
+        )
+        self.assertQuerySetEqual(
+            publisher_pages,
+            [
+                {"publisher": self.p2.id, "sum_pages": 528},
+                {"publisher": self.p4.id, "sum_pages": 946},
+                {"publisher": self.p1.id, "sum_pages": 747},
+                {"publisher": self.p3.id, "sum_pages": 1482},
+            ],
+        )
+
     def test_empty_result_optimization(self):
         with self.assertNumQueries(0):
             self.assertEqual(