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

On Fri, 2025-07-25 at 14:10 -0400, Tom Lane wrote:
> After looking at the code I remembered that the parser might be taking
> this as a type coercion request.  With that idea, I can duplicate the
> observed behavior like so:
>
> regression=# select _sa_setup_role('af_repo_app');
> INFO:  af_repo_app
>  _sa_setup_role
> ----------------
>  Done
> (1 row)
>
> regression=# create domain _sa_setup_role as varchar[];
> CREATE DOMAIN
> regression=# 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.
>
> So ... any chance you have a data type named _sa_setup_role?

... it could also be a type "sa_setup_role", and "_sa_setup_role"
is interpreted as the corresponding array type:

  CREATE DOMAIN sa_setup_role AS varchar;

  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.

Yours,
Laurenz Albe