Commit f717ef08 authored by Andrew Godwin's avatar Andrew Godwin
Browse files

Fixed #22833: Autodetector not doing through mapping correctly

parent 24afb1d7

django/db/migrations/autodetector.py

+5 −1
Original line number Diff line number Diff line
@@ -127,7 +127,11 @@ class MigrationAutodetector(object): 
            new_model_state = self.to_state.models[app_label, model_name]

            self.old_field_keys.update((app_label, model_name, x) for x, y in old_model_state.fields)

            self.new_field_keys.update((app_label, model_name, x) for x, y in new_model_state.fields)

            # Through model stuff



        # Through model map generation

        for app_label, model_name in sorted(self.old_model_keys):

            old_model_name = self.renamed_models.get((app_label, model_name), model_name)

            old_model_state = self.from_state.models[app_label, old_model_name]

            for field_name, field in old_model_state.fields:

                old_field = self.old_apps.get_model(app_label, old_model_name)._meta.get_field_by_name(field_name)[0]

                if hasattr(old_field, "rel") and hasattr(old_field.rel, "through") and not old_field.rel.through._meta.auto_created:

tests/migrations/test_autodetector.py

+15 −0
Original line number Diff line number Diff line
@@ -750,6 +750,21 @@ class AutodetectorTests(TestCase): 
        self.assertEqual(action.__class__.__name__, "DeleteModel")

        self.assertEqual(action.name, "Attribution")



    def test_many_to_many_removed_before_through_model_2(self):

        """

        Removing a model that contains a ManyToManyField and the

        "through" model in the same change must remove

        the field before the model to maintain consistency.

        """

        before = self.make_project_state([self.book_with_multiple_authors_through_attribution, self.author_name, self.attribution])

        after = self.make_project_state([self.author_name])  # removes both the through model and ManyToMany

        autodetector = MigrationAutodetector(before, after)

        changes = autodetector._detect_changes()

        # Right number of migrations?

        self.assertNumberMigrations(changes, 'otherapp', 1)

        # Right number of actions?

        self.assertOperationTypes(changes, 'otherapp', 0, ["RemoveField", "RemoveField", "RemoveField", "DeleteModel", "DeleteModel"])



    def test_m2m_w_through_multistep_remove(self):

        """

        A model with a m2m field that specifies a "through" model cannot be removed in the same