From fe1cb62f5c3f87fafc4a6b52fee2ccc6c80c41e2 Mon Sep 17 00:00:00 2001 From: Simon Charette Date: Sat, 3 Feb 2024 01:10:41 -0500 Subject: [PATCH] Refs #35149 -- Made equivalent db_default alterations noops. This allows for an easier transition of preserving the literal nature of non-compilable db_default. --- django/db/backends/base/schema.py | 8 ++++++++ tests/schema/tests.py | 17 +++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/django/db/backends/base/schema.py b/django/db/backends/base/schema.py index dad3f8d916a1..ed91c6ab1b4c 100644 --- a/django/db/backends/base/schema.py +++ b/django/db/backends/base/schema.py @@ -1640,6 +1640,14 @@ def _field_should_be_altered(self, old_field, new_field, ignore=None): ): old_kwargs.pop("to", None) new_kwargs.pop("to", None) + # db_default can take many form but result in the same SQL. + if ( + old_kwargs.get("db_default") + and new_kwargs.get("db_default") + and self.db_default_sql(old_field) == self.db_default_sql(new_field) + ): + old_kwargs.pop("db_default") + new_kwargs.pop("db_default") return self.quote_name(old_field.column) != self.quote_name( new_field.column ) or (old_path, old_args, old_kwargs) != (new_path, new_args, new_kwargs) diff --git a/tests/schema/tests.py b/tests/schema/tests.py index cde3d7f99146..04ad299aa63a 100644 --- a/tests/schema/tests.py +++ b/tests/schema/tests.py @@ -2316,6 +2316,23 @@ class Meta: columns = self.column_classes(Author) self.assertIn("(missing)", columns["description"][1].default) + @isolate_apps("schema") + def test_db_default_equivalent_sql_noop(self): + class Author(Model): + name = TextField(db_default=Value("foo")) + + class Meta: + app_label = "schema" + + with connection.schema_editor() as editor: + editor.create_model(Author) + + new_field = TextField(db_default="foo") + new_field.set_attributes_from_name("name") + new_field.model = Author + with connection.schema_editor() as editor, self.assertNumQueries(0): + editor.alter_field(Author, Author._meta.get_field("name"), new_field) + @skipUnlessDBFeature( "supports_column_check_constraints", "can_introspect_check_constraints" )