Re: making the backend's json parser work in frontend code

I wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> Is the example of CreateDestReceiver() sufficient to show that this is
>> not a problem in practice?

> Dunno. I don't see any warnings about that in the buildfarm, but
> that's not a very large sample of non-gcc compilers.

BTW, now that I think about it, CreateDestReceiver is not up to project
standards anyway, in that it fails to provide reasonable behavior in
the case where what's passed is not a legal value of the enum.
What you'll get, if you're lucky, is a SIGABRT crash with no
indication of the cause --- or if you're not lucky, some very
hard-to-debug crash elsewhere as a result of the function returning
a garbage pointer. So independently of whether the current coding
suppresses compiler warnings reliably, I think we ought to replace it
with elog()-and-return-NULL. Admittedly, that's wasting a few bytes
on a case that should never happen ... but we haven't ever hesitated
to do that elsewhere, if it'd make the problem more diagnosable.

IOW, there's a good reason why there are exactly no other uses
of that coding pattern.

regards, tom lane