Re: BUG #19034: Recursive function with sql_body can replace an existing function but can not be created on it's own

I ran a test on my local postgresql server, resulting in the same error as
described.
However, I wonder about the necessity of supporting recursive functions in
the CREATE FUNCTION command alone?
Can someone from the Core team confirm this?

I will try to look into this command, before someone can give a clear
clarification.

On Thu, Aug 28, 2025 at 8:18 PM PG Bug reporting form <
noreply@postgresql.org> wrote:

> The following bug has been logged on the website:
>
> Bug reference:      19034
> Logged by:          Katja Henke
> Email address:      katja.henke@foo.ag
> PostgreSQL version: 15.3
> Operating system:   Linux
> Description:
>
> An existing function can be converted into a recursive function that uses
> sql_body. But it is not possible to create this same recursive function
> using CREATE FUNCTION. In other words: if you managed to have a recursive
> function with sql_body in your database, you can't simply restore a dump of
> this database.
>
> The following statement results in
> ERROR:  42883: function pg_temp.do_something(integer) does not exist
>
> CREATE FUNCTION pg_temp.do_something(int) RETURNS int
> LANGUAGE sql
> RETURN CASE WHEN $1 % 2 = 1 THEN pg_temp.do_something($1 + 1) ELSE $1 END;
>
> But the combination of the following statements works. It does not matter
> if
> the first function uses sql_body or a string constant.
>
> CREATE FUNCTION pg_temp.do_something(int) RETURNS int
> LANGUAGE sql
> RETURN 42;
>
> CREATE OR REPLACE FUNCTION pg_temp.do_something(int) RETURNS int
> LANGUAGE sql
> RETURN CASE WHEN $1 % 2 = 1 THEN pg_temp.do_something($1 + 1) ELSE $1 END;
>
>