diff --git a/django/db/migrations/operations/fields.py b/django/db/migrations/operations/fields.py index a123d0b057..ebb0ab2c64 100644 --- a/django/db/migrations/operations/fields.py +++ b/django/db/migrations/operations/fields.py @@ -1,5 +1,6 @@ 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) diff --git a/tests/migrations/test_operations.py b/tests/migrations/test_operations.py index 86cfaf546b..7eaae91fcb 100644 --- a/tests/migrations/test_operations.py +++ b/tests/migrations/test_operations.py @@ -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.