Fixed #28900 -- Propagated all selected fields to combinator queries.

Previously, only the selected column aliases would be propagated and
annotations were ignored.

3 files changed, 14 insertions, 13 deletions

diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index d606505cdf..f3aed06d81 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -591,20 +591,15 @@ class SQLCompiler:
                 # generate valid SQL.
                 compiler.elide_empty = False
         parts = ()
+        selected = self.query.selected
         for compiler in compilers:
             try:
                 # If the columns list is limited, then all combined queries
                 # must have the same columns list. Set the selects defined on
                 # the query on all combined queries, if not already set.
-                if not compiler.query.values_select and self.query.values_select:
+                if selected is not None and compiler.query.selected is None:
                     compiler.query = compiler.query.clone()
-                    compiler.query.set_values(
-                        (
-                            *self.query.extra_select,
-                            *self.query.values_select,
-                            *self.query.annotation_select,
-                        )
-                    )
+                    compiler.query.set_values(selected)
                 part_sql, part_args = compiler.as_sql(with_col_aliases=True)
                 if compiler.query.combinator:
                     # Wrap in a subquery if wrapping in parentheses isn't
diff --git a/tests/queries/test_qs_combinators.py b/tests/queries/test_qs_combinators.py
index e130613084..eac1533803 100644
--- a/tests/queries/test_qs_combinators.py
+++ b/tests/queries/test_qs_combinators.py
@@ -282,11 +282,7 @@ class QuerySetSetOperationTests(TestCase):
             )
             .values_list("num", "count")
         )
-        qs2 = (
-            Number.objects.filter(num=2)
-            .extra(select={"count": 1})
-            .values_list("num", "count")
-        )
+        qs2 = Number.objects.filter(num=2).extra(select={"count": 1})
         self.assertCountEqual(qs1.union(qs2), [(1, 0), (2, 1)])
 
     def test_union_with_values_list_on_annotated_and_unannotated(self):
diff --git a/tests/queries/tests.py b/tests/queries/tests.py
index 3621b6cb2c..ec88fa558d 100644
--- a/tests/queries/tests.py
+++ b/tests/queries/tests.py
@@ -1375,6 +1375,16 @@ class Queries1Tests(TestCase):
         self.assertCountEqual(items_after, [self.i2, self.i3, self.i4])
         self.assertCountEqual(items_before, items_after)
 
+    def test_union_values_subquery(self):
+        items = Item.objects.filter(creator=OuterRef("pk"))
+        item_authors = Author.objects.annotate(is_creator=Exists(items)).order_by()
+        reports = Report.objects.filter(creator=OuterRef("pk"))
+        report_authors = Author.objects.annotate(is_creator=Exists(reports)).order_by()
+        all_authors = item_authors.union(report_authors).order_by("is_creator")
+        self.assertEqual(
+            list(all_authors.values_list("is_creator", flat=True)), [False, True]
+        )
+
 
 class Queries2Tests(TestCase):
     @classmethod