id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35635	Adding a field with a default in migrations following an index rename seems to fail	Raphael Gaschignard		"I have the following migration:

{{{
    operations = [
        migrations.RenameIndex(
            model_name=""taggeditem"",
            new_name=""taggit_tagg_content_8fc721_idx"",
            old_fields=(""content_type"", ""object_id""),
        ),
    ]

}}}

I have created another migration after this one:
{{{
    dependencies = [
        (
            ""taggit"",
            ""0006_rename_taggeditem_content_type_object_id_taggit_tagg_content_8fc721_idx"",
        ),
    ]

    operations = [
        migrations.AddField(
            model_name=""taggeditem"",
            name=""created_at"",
            field=models.DateTimeField(
                blank=True, default=django.utils.timezone.now, null=True
            ),
        ),
    ]
}}}

This gives the following for `sqlmigrate`:
{{{
BEGIN;
--
-- Add field created_at to taggeditem
--
CREATE TABLE ""new__taggit_taggeditem"" (""id"" integer NOT NULL PRIMARY KEY AUTOINCREMENT, ""created_at"" datetime NULL, ""object_id"" integer NOT NULL, ""content_type_id"" integer NOT NULL REFERENCES ""django_content_type"" (""id"") DEFERRABLE INITIALLY DEFERRED, ""tag_id"" integer NOT NULL REFERENCES ""taggit_tag"" (""id"") DEFERRABLE INITIALLY DEFERRED, CONSTRAINT ""taggit_taggeditem_content_type_id_object_id_tag_id_4bb97a8e_uniq"" UNIQUE (""content_type_id"", ""object_id"", ""tag_id""));
INSERT INTO ""new__taggit_taggeditem"" (""id"", ""object_id"", ""content_type_id"", ""tag_id"", ""created_at"") SELECT ""id"", ""object_id"", ""content_type_id"", ""tag_id"", '2024-07-27 00:31:47.134946' FROM ""taggit_taggeditem"";
DROP TABLE ""taggit_taggeditem"";
ALTER TABLE ""new__taggit_taggeditem"" RENAME TO ""taggit_taggeditem"";
CREATE INDEX ""taggit_taggeditem_object_id_e2d7d1df"" ON ""taggit_taggeditem"" (""object_id"");
CREATE INDEX ""taggit_taggeditem_content_type_id_9957a03c"" ON ""taggit_taggeditem"" (""content_type_id"");
CREATE INDEX ""taggit_taggeditem_tag_id_f4f5b767"" ON ""taggit_taggeditem"" (""tag_id"");
CREATE INDEX ""taggit_tagg_content_8fc721_idx"" ON ""taggit_taggeditem"" (""content_type_id"", ""object_id"");
CREATE INDEX ""taggit_tagg_content_8fc721_idx"" ON ""taggit_taggeditem"" (""content_type_id"", ""object_id"");
COMMIT;
}}}

Note in particular the creating of two indexes with the same name.


Now, if I don't set a default in the `AddField` operation , the `sqlmigrate` result is simply as follows:

{{{
BEGIN;
--
-- Add field created_at to taggeditem
--
ALTER TABLE ""taggit_taggeditem"" ADD COLUMN ""created_at"" datetime NULL;
COMMIT;
}}}

And if I comment out the `RenameIndex` operation, I only create the index once, not twice, avoiding the issue.

Extra detail: I hit this because I have an index with a name, and then a `RenameIndex` operation that renames it.
It seems like we would expect there to be a cleanup operation during a rename. Instead, it creates the migration twice.

I have only tested this out with the SQLite driver, and I have a suspicion it's only happening there, because... well... this seems like something that would break elsewhere.

Reproduced this with 5.1rc1 and 5.0.6

Reproduction:

- Checkout https://github.com/jazzband/django-taggit/commit/27640cebf6d7f03f5b34d0395bbf85422a6ef51f
- Install Django
- Run `sample_taggit/manage.py migrate`

"	Bug	new	Migrations	5.0	Normal				Unreviewed	0	0	0	0	0	0