diff options
| -rw-r--r-- | django/db/backends/mysql/schema.py | 5 | ||||
| -rw-r--r-- | tests/schema/tests.py | 31 |
2 files changed, 35 insertions, 1 deletions
diff --git a/django/db/backends/mysql/schema.py b/django/db/backends/mysql/schema.py index 64771fe6c3..e61445e46c 100644 --- a/django/db/backends/mysql/schema.py +++ b/django/db/backends/mysql/schema.py @@ -121,7 +121,10 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor): ) def remove_constraint(self, model, constraint): - if isinstance(constraint, UniqueConstraint): + if ( + isinstance(constraint, UniqueConstraint) + and constraint.create_sql(model, self) is not None + ): self._create_missing_fk_index( model, fields=constraint.fields, diff --git a/tests/schema/tests.py b/tests/schema/tests.py index e325fa0c88..c0f0e52a63 100644 --- a/tests/schema/tests.py +++ b/tests/schema/tests.py @@ -2676,6 +2676,37 @@ class SchemaTests(TransactionTestCase): with self.assertRaises(IntegrityError): Tag.objects.create(title="bar", slug="foo") + def test_remove_ignored_unique_constraint_not_create_fk_index(self): + with connection.schema_editor() as editor: + editor.create_model(Author) + editor.create_model(Book) + constraint = UniqueConstraint( + "author", + condition=Q(title__in=["tHGttG", "tRatEotU"]), + name="book_author_condition_uniq", + ) + # Add unique constraint. + with connection.schema_editor() as editor: + editor.add_constraint(Book, constraint) + old_constraints = self.get_constraints_for_column( + Book, + Book._meta.get_field("author").column, + ) + # Remove unique constraint. + with connection.schema_editor() as editor: + editor.remove_constraint(Book, constraint) + new_constraints = self.get_constraints_for_column( + Book, + Book._meta.get_field("author").column, + ) + # Redundant foreign key index is not added. + self.assertEqual( + len(old_constraints) - 1 + if connection.features.supports_partial_indexes + else len(old_constraints), + len(new_constraints), + ) + @skipUnlessDBFeature("allows_multiple_constraints_on_same_fields") def test_remove_field_unique_does_not_remove_meta_constraints(self): with connection.schema_editor() as editor: |