PostgreSQL Bug with simple function unexpectedly treating varchar parameter as an array

On Wednesday, August 6, 2025, Rumpi Gravenstein <rgravens(at)gmail(dot)com> wrote:

>
> xxx_pub_dev_2_db=# drop FUNCTION if exists _sa_setup_role;
> DROP FUNCTION
> xxx_pub_dev_2_db=# select proname, pronamespace, oid from pg_proc where
> proname like '%sa_setup%';
> proname | pronamespace | oid
> ---------+--------------+-----
> (0 rows)
>
> xxx_pub_dev_2_db=# select _sa_setup_role('af_repo_app');
> ERROR: malformed array literal: "af_repo_app"
> LINE 1: select _sa_setup_role('af_repo_app');
> ^
> DETAIL: Array value must start with "{" or dimension information.
> xxx_pub_dev_2_db=#
>

Yeah, we’ve already pretty much decided this function has nothing to do
with it. Go look at pg_type per the last example demonstrating the same
error without the involvement of any user-defined function.

David J.