Re: options for RAISE statement

"Pavel Stehule" <pavel.stehule@gmail.com> writes:
> this patch adds possibility to set additional options (SQLSTATE,
> DETAIL, DETAIL_LOG and HINT) for RAISE statement,

I looked this over briefly.  A couple of comments:

* Raising errors via hard-coded SQLSTATEs seems pretty unfriendly,
at least for cases where we are reporting built-in errors.  Wouldn't
it be better to be able to raise errors using the same SQLSTATE names
that are recognized in EXCEPTION clauses?

* If we are going to let people throw random SQLSTATEs, there had better
be a way to name those same SQLSTATEs in EXCEPTION.

* I don't really like exposing DETAIL_LOG in this.  That was a spur of
the moment addition and we might take it out again; I think it's way
premature to set it in stone by exposing it as a plpgsql feature.

* Please avoid using errstart() directly.  This is unwarranted intimacy
with elog.h's implementation and I also think it will have unpleasant
behavior if an error occurs while evaluating the RAISE arguments.
(In fact, I think a user could easily force a backend PANIC that way.)
The approved way to deal with ereport options that might not be there
is like this:

    ereport(ERROR,
            ( ...,
             have_sqlstate ? errcode(...) : 0,
              ...

That is, you should evaluate all the options into local variables
and then do one normal ereport call.

* // comments are against our coding conventions.

            regards, tom lane