Failed to sync_enum_values for array of enums with default value

[uriyyo]

For instance, when I have a structure like this:

create type email_template_enum as enum
(
    'welcome',
    'password_reset',
    'email_verification'
);

create table users
(
    id              uuid                  default gen_random_uuid()           not null primary key,
    disabled_emails email_template_enum[] default '{}'::email_template_enum[] not null
);

And when I try to add another value to email_template_enum:

op.sync_enum_values(
    "public",
    "email_template_enum",
    [
        "welcome",
        "password_reset",
        "email_verification",
        "email_changed",
    ]
    [
        TableReference(
            "users",
            "disabled_emails",
            column_type=ColumnType.ARRAY,
            existing_server_default="'{}'::email_template_enum[]",
        ),
    ],
    enum_values_to_rename=[],
)

It will fail:

sqlalchemy.exc.DBAPIError: (sqlalchemy.dialects.postgresql.asyncpg.Error) <class 'asyncpg.exceptions.InvalidTextRepresentationError'>: invalid input value for enum email_template_enum: "{}"
[SQL: ALTER TABLE public.users ALTER COLUMN disabled_emails SET DEFAULT '{}'::email_template_enum]
(Background on this error at: https://sqlalche.me/e/20/dbapi)

Default value should be:

 '{}'::email_template_enum[]

Not:

 '{}'::email_template_enum