Fixed #21029: Test for previously-commited SchemaEditor.__exit__ bug.

tests/schema/tests.py

@@ -643,3 +643,16 @@ class SchemaTests(TransactionTestCase):
         self.assertTrue(
             connection.introspection.get_indexes(connection.cursor(), Tag._meta.db_table)['slug']['primary_key'],
         )
+
+    def test_context_manager_exit(self):
+        """
+        Ensures transaction is correctly closed when an error occurs
+        inside a SchemaEditor context.
+        """
+        class SomeError(Exception):
+            pass
+        try:
+            with connection.schema_editor() as editor:
+                raise SomeError
+        except SomeError:
+            self.assertFalse(connection.in_atomic_block)