Fixed #29987 -- Detected unmanaged model deletions.

django/db/migrations/autodetector.py

@@ -722,10 +722,6 @@ class MigrationAutodetector:
         for app_label, model_name in all_deleted_models:
             model_state = self.from_state.models[app_label, model_name]
             model = self.old_apps.get_model(app_label, model_name)
-            if not model._meta.managed:
-                # Skip here, no need to handle fields for unmanaged models
-                continue
-
             # Gather related fields
             related_fields = {}
             for field in model._meta.local_fields:

tests/migrations/test_autodetector.py

@@ -1662,6 +1662,11 @@ class AutodetectorTests(TestCase):
         self.assertOperationTypes(changes, 'testapp', 0, ["CreateModel"])
         self.assertOperationAttributes(changes, 'testapp', 0, 0, name="AuthorUnmanaged", options={"managed": False})
 
+    def test_unmanaged_delete(self):
+        changes = self.get_changes([self.author_empty, self.author_unmanaged], [self.author_empty])
+        self.assertNumberMigrations(changes, 'testapp', 1)
+        self.assertOperationTypes(changes, 'testapp', 0, ['DeleteModel'])
+
     def test_unmanaged_to_managed(self):
         # Now, we test turning an unmanaged model into a managed model
         changes = self.get_changes(