From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Dean Rasheed <dean.a.rasheed@gmail.com>,
        Michael Paquier <michael@paquier.xyz>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        =?UTF-8?Q?L=C3=A6titia_Avrot?= <laetitia.avrot@gmail.com>
Subject: Re: pgsql: Add support for hyperbolic functions, as well as log10().
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Wed, 13 Mar 2019 22:40:18 -0400"
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Date: Wed, 13 Mar 2019 22:44:30 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Mar 13, 2019 at 10:39 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> No, but that's not the hazard.  I have a very fresh-in-mind example:
>> at one point while tweaking Laetitia's patch, I'd accidentally changed
>> datanh so that it called tanh not atanh.  The previous set of tests did
>> not reveal that :-(

> Well, that was a goof, but it's not likely that such a regression will
> ever be reintroduced.

Sure, but how about this for another example: maybe a given platform
hasn't got these functions (or they're in a different library we
didn't pull in), but you don't see a failure until you actually
call them.  We try to set up our link options so that that sort
of failure is reported at build time, but I wouldn't care to bet
that we've succeeded at that everywhere.

			regards, tom lane