Re: wrong error message related to unsupported feature

Hi

út 18. 3. 2025 v 21:33 odesílatel Álvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
napsal:

> On 2025-Mar-18, Pavel Stehule wrote:
>
> > Maybe I found a bug
> >
> > (2025-03-18 19:28:06) postgres=# create table foo(a int constraint gzero
> > check(a > 10) NOT ENFORCED);
> > CREATE TABLE
> > (2025-03-18 19:29:37) postgres=# insert into foo values(0);
> > INSERT 0 1
> > (2025-03-18 19:29:49) postgres=# insert into foo values(6);
> > INSERT 0 1
> > (2025-03-18 19:29:55) postgres=# alter table foo alter constraint gzero
> > enforced;
> > ERROR: FOREIGN KEY constraints cannot be marked ENFORCED
> > LINE 1: alter table foo alter constraint gzero enforced;
> >
> > I know so altering enforcing constraint is not supported yet, but the
> error
> > message is surely wrong
>
> Yep, this is a bug all right -- I reported this and related problems a
> few days ago [1]. There's a proposal in that thread for how to fix this
> (see Amul's email [2] and my followup), but I haven't had time to fully
> implement it. If you want to give it a couple of hours to complete it,
> that'd be great. I have a couple of patches that I need to handle
> before coming back to that.
>
> [1] https://postgr.es/m/202503041822.aobpqke3igvb@alvherre.pgsql
> [2]
> https://postgr.es/m/CAAJ_b97hd-jMTS7AjgU6TDBCzDx_KyuKxG+K-DtYmOieg+giyQ@mail.gmail.com

I am looking this issue, and I am not sure if proposed way is the best

cannot we change processCASbits just like ?

if (cas_bits & (CAS_DEFERRABLE | CAS_INITIALLY_DEFERRED))
{
if (deferrable)
*deferrable = true;
else if (constrType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s is CHECK, UNIQUE, or similar */
constrType ?
errmsg("%s constraints cannot be marked DEFERRABLE",
constrType) :
errmsg("constraint cannot be marked DEFERRABLE"),
parser_errposition(location)));
}
...

Probably can be better to not try to read from catalog in this moment, and
then we can accept so we don't know constraint type

Regards

Pavel

>
> --
> Álvaro Herrera PostgreSQL Developer —
> https://www.EnterpriseDB.com/
>