Commit a338e077 authored by Andrew Godwin's avatar Andrew Godwin
Browse files

Fixed #23101: Prefer doing deletes before creates in autodetector. 

Makes declined or missed renames still work (but drop data).
parent b9daa4f0

django/db/migrations/autodetector.py

+16 −10
Original line number Diff line number Diff line
@@ -160,15 +160,16 @@ class MigrationAutodetector(object): 
                    self.through_users[through_key] = (app_label, old_model_name, field_name)



        # Generate non-rename model operations

        self.generate_created_models()

        self.generate_deleted_models()

        self.generate_created_proxies()

        self.generate_created_models()

        self.generate_deleted_proxies()

        self.generate_created_proxies()

        self.generate_altered_options()



        # Generate field operations

        self.generate_added_fields()

        self.generate_renamed_fields()

        self.generate_removed_fields()

        self.generate_added_fields()

        self.generate_altered_fields()

        self.generate_altered_unique_together()

        self.generate_altered_index_together()
@@ -682,17 +683,17 @@ class MigrationAutodetector(object): 
                ),

            )



    def generate_added_fields(self):

        # New fields

    def generate_renamed_fields(self):

        """

        Works out renamed fields

        """

        self.renamed_fields = {}

        for app_label, model_name, field_name in sorted(self.new_field_keys - self.old_field_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]

            new_model_state = self.to_state.models[app_label, model_name]

            field = self.new_apps.get_model(app_label, model_name)._meta.get_field_by_name(field_name)[0]

            # Scan to see if this is actually a rename!

            field_dec = self.deep_deconstruct(field)

            found_rename = False

            for rem_app_label, rem_model_name, rem_field_name in sorted(self.old_field_keys - self.new_field_keys):

                if rem_app_label == app_label and rem_model_name == model_name:

                    old_field_dec = self.deep_deconstruct(old_model_state.get_field_by_name(rem_field_name))
@@ -713,10 +714,15 @@ class MigrationAutodetector(object): 
                            self.old_field_keys.remove((rem_app_label, rem_model_name, rem_field_name))

                            self.old_field_keys.add((app_label, model_name, field_name))

                            self.renamed_fields[app_label, model_name, field_name] = rem_field_name

                            found_rename = True

                            break

            if found_rename:

                continue





    def generate_added_fields(self):

        """

        Fields that have been added

        """

        for app_label, model_name, field_name in sorted(self.new_field_keys - self.old_field_keys):

            field = self.new_apps.get_model(app_label, model_name)._meta.get_field_by_name(field_name)[0]

            # Fields that are foreignkeys/m2ms depend on stuff

            dependencies = []

            if field.rel and field.rel.to:

tests/migrations/test_autodetector.py

+10 −25
Original line number Diff line number Diff line
@@ -278,16 +278,10 @@ class AutodetectorTests(TestCase): 
        after = self.make_project_state([self.author_name_renamed])

        autodetector = MigrationAutodetector(before, after, MigrationQuestioner({"ask_rename": True}))

        changes = autodetector._detect_changes()

        # Right number of migrations?

        self.assertEqual(len(changes['testapp']), 1)

        # Right number of actions?

        migration = changes['testapp'][0]

        self.assertEqual(len(migration.operations), 1)

        # Right action?

        action = migration.operations[0]

        self.assertEqual(action.__class__.__name__, "RenameField")

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

        self.assertEqual(action.new_name, "names")

        # Check

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

        self.assertOperationTypes(changes, 'testapp', 0, ["RenameField"])

        self.assertOperationAttributes(changes, 'testapp', 0, 0, old_name="name", new_name="names")



    def test_rename_model(self):

        "Tests autodetection of renamed models"
@@ -731,21 +725,12 @@ class AutodetectorTests(TestCase): 
        after = self.make_project_state([self.author_with_publisher, self.publisher])

        autodetector = MigrationAutodetector(before, after)

        changes = autodetector._detect_changes()

        # Right number of migrations?

        self.assertEqual(len(changes['testapp']), 1)

        # Right number of actions?

        migration = changes['testapp'][0]

        self.assertEqual(len(migration.operations), 3)

        # Right actions?

        action = migration.operations[0]

        self.assertEqual(action.__class__.__name__, "CreateModel")

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

        action = migration.operations[1]

        self.assertEqual(action.__class__.__name__, "AddField")

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

        action = migration.operations[2]

        self.assertEqual(action.__class__.__name__, "RemoveField")

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

        # Right result?

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

        self.assertOperationTypes(changes, 'testapp', 0, ["CreateModel", "RemoveField", "AddField"])

        self.assertOperationAttributes(changes, 'testapp', 0, 0, name="Publisher")

        self.assertOperationAttributes(changes, 'testapp', 0, 1, name="publisher_name")

        self.assertOperationAttributes(changes, 'testapp', 0, 2, name="publisher")



    def test_foreign_key_removed_before_target_model(self):

        """