Fixed #25945, #26292 -- Refactored MigrationLoader.build_graph()

tests/migrations/test_migrations_squashed_ref_squashed/app1/1_auto.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_ref_squashed/app1/2_auto.py

@@ -0,0 +1,9 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "1_auto")]

tests/migrations/test_migrations_squashed_ref_squashed/app1/2_squashed_3.py

@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    replaces = [
+        ("app1", "2_auto"),
+        ("app1", "3_auto"),
+    ]
+
+    dependencies = [("app1", "1_auto"), ("app2", "1_squashed_2")]

tests/migrations/test_migrations_squashed_ref_squashed/app1/3_auto.py

@@ -0,0 +1,9 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "2_auto"), ("app2", "2_auto")]

tests/migrations/test_migrations_squashed_ref_squashed/app1/4_auto.py

@@ -0,0 +1,9 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "2_squashed_3")]