Fixed #29721 -- Ensured migrations are applied and recorded atomically.

tests/migrations/test_executor.py

@@ -1,3 +1,5 @@
+from unittest import mock
+
 from django.apps.registry import apps as global_apps
 from django.db import connection
 from django.db.migrations.exceptions import InvalidMigrationPlan
@@ -5,7 +7,9 @@ from django.db.migrations.executor import MigrationExecutor
 from django.db.migrations.graph import MigrationGraph
 from django.db.migrations.recorder import MigrationRecorder
 from django.db.utils import DatabaseError
-from django.test import TestCase, modify_settings, override_settings
+from django.test import (
+    TestCase, modify_settings, override_settings, skipUnlessDBFeature,
+)
 
 from .test_base import MigrationTestBase
 
@@ -649,6 +653,22 @@ class ExecutorTests(MigrationTestBase):
             recorder.applied_migrations(),
         )
 
+    # When the feature is False, the operation and the record won't be
+    # performed in a transaction and the test will systematically pass.
+    @skipUnlessDBFeature('can_rollback_ddl')
+    @override_settings(MIGRATION_MODULES={'migrations': 'migrations.test_migrations'})
+    def test_migrations_applied_and_recorded_atomically(self):
+        """Migrations are applied and recorded atomically."""
+        executor = MigrationExecutor(connection)
+        with mock.patch('django.db.migrations.executor.MigrationExecutor.record_migration') as record_migration:
+            record_migration.side_effect = RuntimeError('Recording migration failed.')
+            with self.assertRaisesMessage(RuntimeError, 'Recording migration failed.'):
+                executor.migrate([('migrations', '0001_initial')])
+        # The migration isn't recorded as applied since it failed.
+        migration_recorder = MigrationRecorder(connection)
+        self.assertFalse(migration_recorder.migration_qs.filter(app='migrations', name='0001_initial').exists())
+        self.assertTableNotExists('migrations_author')
+
 
 class FakeLoader:
     def __init__(self, graph, applied):