Fix AlterField migrations that are related to a RenameModel migration (107c9f54) · Commits · Dom Sekotill / django

django/db/migrations/operations/fields.py

+12 −5

Original line number	Diff line number	Diff line
		from django.db import router
		from django.db.models.fields import NOT_PROVIDED
		from django.utils import six
		from .base import Operation


		@@ -116,11 +117,17 @@ class AlterField(Operation):
		from_model = from_state.render().get_model(app_label, self.model_name)
		to_model = to_state.render().get_model(app_label, self.model_name)
		if router.allow_migrate(schema_editor.connection.alias, to_model):
		schema_editor.alter_field(
		from_model,
		from_model._meta.get_field_by_name(self.name)[0],
		to_model._meta.get_field_by_name(self.name)[0],
		)
		from_field = from_model._meta.get_field_by_name(self.name)[0]
		to_field = to_model._meta.get_field_by_name(self.name)[0]
		# If the field is a relatedfield with an unresolved rel.to, just
		# set it equal to the other field side. Bandaid fix for AlterField
		# migrations that are part of a RenameModel change.
		if from_field.rel and from_field.rel.to:
		if isinstance(from_field.rel.to, six.string_types):
		from_field.rel.to = to_field.rel.to
		elif isinstance(to_field.rel.to, six.string_types):
		to_field.rel.to = from_field.rel.to
		schema_editor.alter_field(from_model, from_field, to_field)

		def database_backwards(self, app_label, schema_editor, from_state, to_state):
		self.database_forwards(app_label, schema_editor, from_state, to_state)

tests/migrations/test_operations.py

+41 −0

Original line number	Diff line number	Diff line
		@@ -226,6 +226,47 @@ class OperationTests(MigrationTestBase):
		self.assertTableExists("test_dlmo_pony")
		self.assertTableNotExists("test_rnmo_horse")

		def test_rename_model_with_related(self):
		"""
		Tests the real-world combo of a RenameModel operation with AlterField
		for a related field.
		"""
		project_state = self.set_up_test_model(
		"test_rnmowr", related_model=True)
		# Test the state alterations
		model_operation = migrations.RenameModel("Pony", "Horse")
		new_state = project_state.clone()
		model_operation.state_forwards("test_rnmowr", new_state)
		self.assertNotIn(("test_rnmowr", "pony"), new_state.models)
		self.assertIn(("test_rnmowr", "horse"), new_state.models)

		self.assertEqual(
		"Pony",
		project_state.render().get_model("test_rnmowr", "rider")
		._meta.get_field_by_name("pony")[0].rel.to._meta.object_name)
		field_operation = migrations.AlterField(
		"Rider", "pony", models.ForeignKey("Horse"))
		field_operation.state_forwards("test_rnmowr", new_state)
		self.assertEqual(
		"Horse",
		new_state.render().get_model("test_rnmowr", "rider")
		._meta.get_field_by_name("pony")[0].rel.to._meta.object_name)

		# Test the database alterations
		self.assertTableExists("test_rnmowr_pony")
		self.assertTableNotExists("test_rnmowr_horse")
		with connection.schema_editor() as editor:
		model_operation.database_forwards("test_rnmowr", editor, project_state, new_state)
		field_operation.database_forwards("test_rnmowr", editor, project_state, new_state)
		self.assertTableNotExists("test_rnmowr_pony")
		self.assertTableExists("test_rnmowr_horse")
		# And test reversal
		with connection.schema_editor() as editor:
		field_operation.database_backwards("test_rnmowr", editor, new_state, project_state)
		model_operation.database_backwards("test_rnmowr", editor, new_state, project_state)
		self.assertTableExists("test_rnmowr_pony")
		self.assertTableNotExists("test_rnmowr_horse")

		def test_add_field(self):
		"""
		Tests the AddField operation.