Commit 92a10f55 authored by Andrew Godwin's avatar Andrew Godwin
Browse files

Autodetect field renames. HAHAHA. AHAHAHAHA. YES.

parent 0e8ee50e

django/db/migrations/autodetector.py

+20 −1
Original line number Diff line number Diff line
@@ -68,7 +68,26 @@ class MigrationAutodetector(object): 
            old_field_names = set([x for x, y in old_model_state.fields])

            new_field_names = set([x for x, y in new_model_state.fields])

            for field_name in new_field_names - old_field_names:

                field = [y for x, y in new_model_state.fields if x == field_name][0]

                field = new_model_state.get_field_by_name(field_name)

                # Scan to see if this is actually a rename!

                field_dec = field.deconstruct()[1:]

                found_rename = False

                for removed_field_name in (old_field_names - new_field_names):

                    if old_model_state.get_field_by_name(removed_field_name).deconstruct()[1:] == field_dec:

                        self.add_to_migration(

                            app_label,

                            operations.RenameField(

                                model_name = model_name,

                                old_name = removed_field_name,

                                new_name = field_name,

                            )

                        )

                        old_field_names.remove(removed_field_name)

                        new_field_names.remove(field_name)

                        found_rename = True

                        break

                if found_rename:

                    continue

                # You can't just add NOT NULL fields with no default

                if not field.null and not field.has_default():

                    field.default = self.questioner.ask_not_null_addition(field_name, model_name)

tests/migrations/test_autodetector.py

+20 −1
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ class AutodetectorTests(TestCase): 
    author_empty = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True))])

    author_name = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200))])

    author_name_longer = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=400))])

    author_name_renamed = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("names", models.CharField(max_length=200))])

    other_pony = ModelState("otherapp", "Pony", [("id", models.AutoField(primary_key=True))])

    other_stable = ModelState("otherapp", "Stable", [("id", models.AutoField(primary_key=True))])

    third_thing = ModelState("thirdapp", "Thing", [("id", models.AutoField(primary_key=True))])
@@ -22,7 +23,7 @@ class AutodetectorTests(TestCase): 
        "Shortcut to make ProjectStates from lists of predefined models"

        project_state = ProjectState()

        for model_state in model_states:

            project_state.add_model_state(model_state)

            project_state.add_model_state(model_state.clone())

        return project_state



    def test_arrange_for_graph(self):
@@ -148,3 +149,21 @@ class AutodetectorTests(TestCase): 
        action = migration.operations[0]

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

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



    def test_rename_field(self):

        "Tests autodetection of renamed fields"

        # Make state

        before = self.make_project_state([self.author_name])

        after = self.make_project_state([self.author_name_renamed])

        autodetector = MigrationAutodetector(before, after)

        changes = autodetector.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")