Fixed #23733 -- Fixed squashing migrations that depend on multiple apps.

django/db/migrations/loader.py

@@ -221,8 +221,15 @@ class MigrationLoader(object):
                 for child_key in reverse_dependencies.get(replaced, set()):
                     if child_key in migration.replaces:
                         continue
-                    normal[child_key].dependencies.remove(replaced)
-                    normal[child_key].dependencies.append(key)
+                    # child_key may appear in a replacement
+                    if child_key in reverse_replacements:
+                        for replaced_child_key in reverse_replacements[child_key]:
+                            if replaced in replacing[replaced_child_key].dependencies:
+                                replacing[replaced_child_key].dependencies.remove(replaced)
+                                replacing[replaced_child_key].dependencies.append(key)
+                    else:
+                        normal[child_key].dependencies.remove(replaced)
+                        normal[child_key].dependencies.append(key)
             normal[key] = migration
             # Mark the replacement as applied if all its replaced ones are
             if all(applied_statuses):

tests/migrations/test_loader.py

@@ -239,6 +239,27 @@ class LoaderTests(TestCase):
 
         recorder.flush()
 
+    @override_settings(MIGRATION_MODULES={
+        "app1": "migrations.test_migrations_squashed_complex_multi_apps.app1",
+        "app2": "migrations.test_migrations_squashed_complex_multi_apps.app2",
+    })
+    @modify_settings(INSTALLED_APPS={'append': [
+        "migrations.test_migrations_squashed_complex_multi_apps.app1",
+        "migrations.test_migrations_squashed_complex_multi_apps.app2",
+    ]})
+    def test_loading_squashed_complex_multi_apps(self):
+        loader = MigrationLoader(connection)
+        loader.build_graph()
+
+        plan = set(loader.graph.forwards_plan(('app1', '4_auto')))
+        expected_plan = set([
+            ('app1', '4_auto'),
+            ('app1', '2_squashed_3'),
+            ('app2', '1_squashed_2'),
+            ('app1', '1_auto')
+        ])
+        self.assertEqual(plan, expected_plan)
+
     @override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations_squashed_erroneous"})
     def test_loading_squashed_erroneous(self):
         "Tests loading a complex but erroneous set of squashed migrations"

tests/migrations/test_migrations_squashed_complex_multi_apps/app1/1_auto.py

@@ -0,0 +1,11 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

tests/migrations/test_migrations_squashed_complex_multi_apps/app1/2_auto.py

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "1_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

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

@@ -0,0 +1,18 @@
+# -*- 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", "2_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

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

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "2_auto"), ("app2", "2_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

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

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "3_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

tests/migrations/test_migrations_squashed_complex_multi_apps/app2/1_auto.py

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app1", "1_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

tests/migrations/test_migrations_squashed_complex_multi_apps/app2/1_squashed_2.py

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    replaces = [
+        ("app2", "1_auto"),
+        ("app2", "2_auto"),
+    ]
+
+    dependencies = [("app1", "1_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]

tests/migrations/test_migrations_squashed_complex_multi_apps/app2/2_auto.py

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("app2", "1_auto")]
+
+    operations = [
+        migrations.RunPython(lambda apps, schema_editor: None)
+    ]