From: Tom Lane <tgl@sss.pgh.pa.us>
To: Erik Wienhold <ewie@ewie.name>
cc: "David G. Johnston" <david.g.johnston@gmail.com>,
        Chris BSomething <xpusostomos@gmail.com>,
        pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18715: replace() function silently fails if 3rd argument is
 null
In-reply-to: <c4804767-5c7e-4103-9d1e-0c6c2e3433d3@ewie.name>
References: <18715-7035b5d78571887e@postgresql.org>
 <CAKFQuwaFtdrDPryMUfBy_+DnsrGishCuXHc+doVLjdczhWWP1w@mail.gmail.com>
 <CADrHaBGAgjGCG_d0=myn+Rq1qNSduDA=_f=B8bLRzQm=E-sL4g@mail.gmail.com>
 <CAKFQuwZ8HCXZF+dFhW809Zuv+Z6AStQ10kkFiYTC-f79d5U1Ug@mail.gmail.com>
 <3778528.1732034860@sss.pgh.pa.us>
 <c4804767-5c7e-4103-9d1e-0c6c2e3433d3@ewie.name>
Comments: In-reply-to Erik Wienhold <ewie@ewie.name>
	message dated "Tue, 19 Nov 2024 23:34:23 +0100"
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-ID: <3966227.1732056048.1@sss.pgh.pa.us>
Content-Transfer-Encoding: 8bit
Date: Tue, 19 Nov 2024 17:40:48 -0500
Message-ID: <3966228.1732056048@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/3966228.1732056048%40sss.pgh.pa.us>
Precedence: bulk

Erik Wienhold <ewie@ewie.name> writes:
> On 2024-11-19 17:47 +0100, Tom Lane wrote:
>> I thought we documented somewhere that built-in functions are strict
>> unless explicitly stated otherwise ... but I sure can't find that
>> statement right now.

> Perhaps this one?:
>> (Most internal functions expect to be declared “strict”.)
>> https://www.postgresql.org/docs/current/xfunc-internal.html

I did see that one, but it's not exactly in an obvious-to-novices
place.

David was working on a new docs section that would talk more about
SQL NULLs in general.  Maybe that would be a reasonable place?
An alternative could be somewhere early in func.sgml, but that chapter
doesn't really have anything I would call an overview section.

			regards, tom lane