Re: Nicely exiting PG_TRY and PG_CATCH

> Yeah, you can't return or goto out of the PG_TRY part.

So this is a problem if the check would ever work.
(Sorry for such a delayed answer.)

Then we need to fix it. Attached is a minimal patch, which changes nothing
except for correct PG_TRY exiting.
Isn't it better this way?

CCing to Peter Eisentraut, whose patch originally introduced these returns.
Peter, will such a patch work somehow against your initial idea?

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Mikhail A. Gribkov

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On Sat, Oct 8, 2022 at 12:19 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Mikhail Gribkov <youzhick(at)gmail(dot)com> writes:
> > Usually it's not a good idea to exit PG_TRY() block via return statement.
> > Otherwise it would leave PG_exception_stack global variable in a wrong
> > state and next ereport() will jump to some junk address.
>
> Yeah, you can't return or goto out of the PG_TRY part.
>
> > Another suspicious case is PG_CATCH block in jsonb_plpython.c:
>
> This should be OK. The PG_CATCH and PG_FINALLY macros are set up so that
> we've fully restored that state *before* we execute any of the
> error-handling code. It would be basically impossible to have a guarantee
> that CATCH blocks never throw errors; they'd be so restricted as to be
> near useless, like signal handlers.
>
> regards, tom lane
>