Fixed #27004 -- Made migrations consistency check ignore unapplied squashed migrations.

tests/migrations/test_loader.py

@@ -381,6 +381,23 @@ class LoaderTests(TestCase):
         with self.assertRaisesMessage(InconsistentMigrationHistory, msg):
             loader.check_consistent_history(connection)
 
+    @override_settings(
+        MIGRATION_MODULES={'migrations': 'migrations.test_migrations_squashed_extra'},
+        INSTALLED_APPS=['migrations'],
+    )
+    def test_check_consistent_history_squashed(self):
+        """
+        MigrationLoader.check_consistent_history() should ignore unapplied
+        squashed migrations that have all of their `replaces` applied.
+        """
+        loader = MigrationLoader(connection=None)
+        recorder = MigrationRecorder(connection)
+        recorder.record_applied('migrations', '0001_initial')
+        recorder.record_applied('migrations', '0002_second')
+        loader.check_consistent_history(connection)
+        recorder.record_applied('migrations', '0003_third')
+        loader.check_consistent_history(connection)
+
     @override_settings(MIGRATION_MODULES={
         "app1": "migrations.test_migrations_squashed_ref_squashed.app1",
         "app2": "migrations.test_migrations_squashed_ref_squashed.app2",

tests/migrations/test_migrations_squashed_extra/0001_initial.py

@@ -0,0 +1,8 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    pass

tests/migrations/test_migrations_squashed_extra/0001_squashed_0002.py

@@ -0,0 +1,11 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    replaces = [
+        ("migrations", "0001_initial"),
+        ("migrations", "0002_second"),
+    ]

tests/migrations/test_migrations_squashed_extra/0002_second.py

@@ -0,0 +1,8 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [("migrations", "0001_initial")]

tests/migrations/test_migrations_squashed_extra/0003_third.py

@@ -0,0 +1,8 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [("migrations", "0002_second")]