Re: pg_get_functiondef forgets about most GUC_LIST_INPUT GUCs

On Thu, Mar 15, 2018 at 06:48:36PM +0900, Kyotaro HORIGUCHI wrote:
> postgres=# CREATE FUNCTION func_with_set_params() RETURNS integer
>     AS 'select 1;'
>     LANGUAGE SQL
>     set plpgsql.extra_errors to 'shadowed_variables'
>     set work_mem to '48MB'
>     set plpgsql.extra_warnings to 'shadowed_variables';
> ERROR:  the module for variable "plpgsql.extra_errors" is not loaded yet
> DETAIL:  The module must be loaded before referring this variable.

How can you be sure that a parameter actually exists?  A function
definition could as well use a parameter which does not exist, but you
would get this error as well, no?  I find that error and handling a bit
confusing.

> postgres=# load 'plpgsql';
> [...]
> pg_get_functiondef() can work correctly with this even if
> required modules are not loaded.

Yeah, but the neck to any approaches here is that many applications may
rely on the existing behavior, and would miss the fact that they need to
load a module manually.

> But, I suppose it is a bit too big.

That's of course not backpatchable.
--
Michael