Date: Tue, 24 Oct 2023 15:51:16 +0200
From: Christoph Berg <myon@debian.org>
To: Tommy Pavlicek <tommypav122@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,
	Dagfinn Ilmari =?iso-8859-1?Q?Manns=E5ker?= <ilmari@ilmari.org>,
	pgsql-hackers@lists.postgresql.org,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	jian.universality@gmail.com
Subject: Re: [PATCH] Extend ALTER OPERATOR to support adding commutator,
 negator, hashes, and merges
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Re: Tommy Pavlicek
> I've added another patch (0002-require_unused_neg_com-v1.patch) that
> prevents using a commutator or negator that's already part of a pair.

Hmm. I agree with the general idea of adding sanity checks, but this
might be overzealous:

This change is breaking pgsphere which has <@ @> operator pairs, but
for historical reasons also includes alternative spellings of these
operators (both called @ with swapped operand types) which now
explodes because we can't add them with the "proper" commutator and
negators declared (which point to the canonical <@ @> !<@ !@>
operators).

https://github.com/postgrespro/pgsphere/blob/master/pgs_moc_compat.sql.in

We might be able to simply delete the @ operators, but doesn't this
new check break the general possibility to have more than one spelling
for the same operator?

Christoph