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

On Tue, Jan 28, 2020 at 1:32 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> 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.

Well, I might be responsible for the CreateDestReceiver thing -- or I
might not, I haven't checked -- but I do think that style is a bit
cleaner and more elegant. I think it's VERY unlikely that anyone would
ever manage to call it with something that's not a legal value of the
enum, and if they do, I think the chances of surviving are basically
nil, and frankly, I'd rather die. If you asked me where you want me to
store my output and I tell you to store it in the sdklgjsdjgslkdg, you
really should refuse to do anything at all, not just stick my output
someplace-or-other and hope for the best.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company