Fixed #34267 -- Fixed sliced QuerySet.union() crash.

Regression in 3d734c09ff0138441dfe0a59010435871d17950f.

Thanks Raphaël Stefanini for the report.

1 files changed, 12 insertions, 4 deletions

diff --git a/tests/queries/test_qs_combinators.py b/tests/queries/test_qs_combinators.py
index 6358e537ae..96a5b24cc1 100644
--- a/tests/queries/test_qs_combinators.py
+++ b/tests/queries/test_qs_combinators.py
@@ -87,6 +87,15 @@ class QuerySetSetOperationTests(TestCase):
         qs3 = qs1.union(qs2)
         self.assertNumbersEqual(qs3.order_by("num")[2:3], [2])
 
+    def test_union_slice_index(self):
+        Celebrity.objects.create(name="Famous")
+        c1 = Celebrity.objects.create(name="Very famous")
+
+        qs1 = Celebrity.objects.filter(name="nonexistent")
+        qs2 = Celebrity.objects.all()
+        combined_qs = qs1.union(qs2).order_by("name")
+        self.assertEqual(combined_qs[1], c1)
+
     def test_union_order_with_null_first_last(self):
         Number.objects.filter(other_num=5).update(other_num=None)
         qs1 = Number.objects.filter(num__lte=1)
@@ -319,10 +328,10 @@ class QuerySetSetOperationTests(TestCase):
         e1 = ExtraInfo.objects.create(value=7, info="e1")
         a1 = Author.objects.create(name="a1", num=1, extra=e1)
         Author.objects.create(name="a2", num=3, extra=e1)
-        base_qs = Author.objects.select_related("extra")
+        base_qs = Author.objects.select_related("extra").order_by()
         qs1 = base_qs.filter(name="a1")
         qs2 = base_qs.filter(name="a2")
-        self.assertEqual(qs1.union(qs2).first(), a1)
+        self.assertEqual(qs1.union(qs2).order_by("name").first(), a1)
 
     def test_union_with_first(self):
         e1 = ExtraInfo.objects.create(value=7, info="e1")
@@ -455,8 +464,7 @@ class QuerySetSetOperationTests(TestCase):
             captured_sql,
         )
         self.assertEqual(
-            captured_sql.count(connection.ops.limit_offset_sql(None, 1)),
-            3 if connection.features.supports_slicing_ordering_in_compound else 1,
+            captured_sql.count(connection.ops.limit_offset_sql(None, 1)), 1
         )
 
     def test_exists_union_empty_result(self):