Fixed #24725 -- Allowed renaming of target models in ManyToMany relations

This is a regression caused by introducing rendered migration states in
1aa3e09c20 and the _meta refactoring in fb48eb0581.

Thanks to Danilo Bargen for reporting the issue and Marten Kenbeek and
Tim Graham for triaging the bug and providing the initial test case.

django/db/migrations/operations/models.py

@@ -161,7 +161,7 @@ class RenameModel(Operation):
         # Get all of the related objects we need to repoint
         all_related_objects = (
             f for f in model._meta.get_fields(include_hidden=True)
-            if f.auto_created and not f.concrete and not (f.hidden or f.many_to_many)
+            if f.auto_created and not f.concrete and (not f.hidden or f.many_to_many)
         )
         # Rename the model
         state.models[app_label, self.new_name_lower] = state.models[app_label, self.old_name_lower]

docs/releases/1.8.1.txt

@@ -72,6 +72,9 @@ Bugfixes
 * Restored the ability to use iterators as queryset filter arguments
   (:ticket:`24719`).
 
+* Fixed a migration crash when renaming the target model of a many-to-many
+  relation (:ticket:`24725`).
+
 Optimizations
 =============
 

tests/migrations/test_operations.py

@@ -614,6 +614,32 @@ class OperationTests(OperationTestBase):
         self.assertEqual(Rider.objects.count(), 2)
         self.assertEqual(Pony._meta.get_field('riders').remote_field.through.objects.count(), 2)
 
+    def test_rename_m2m_target_model(self):
+        app_label = "test_rename_m2m_target_model"
+        project_state = self.apply_operations(app_label, ProjectState(), operations=[
+            migrations.CreateModel("Rider", fields=[]),
+            migrations.CreateModel("Pony", fields=[
+                ("riders", models.ManyToManyField("Rider")),
+            ]),
+        ])
+        Pony = project_state.apps.get_model(app_label, "Pony")
+        Rider = project_state.apps.get_model(app_label, "Rider")
+        pony = Pony.objects.create()
+        rider = Rider.objects.create()
+        pony.riders.add(rider)
+
+        project_state = self.apply_operations(app_label, project_state, operations=[
+            migrations.RenameModel("Rider", "Rider2"),
+        ])
+        Pony = project_state.apps.get_model(app_label, "Pony")
+        Rider = project_state.apps.get_model(app_label, "Rider2")
+        pony = Pony.objects.create()
+        rider = Rider.objects.create()
+        pony.riders.add(rider)
+        self.assertEqual(Pony.objects.count(), 2)
+        self.assertEqual(Rider.objects.count(), 2)
+        self.assertEqual(Pony._meta.get_field('riders').remote_field.through.objects.count(), 2)
+
     def test_add_field(self):
         """
         Tests the AddField operation.