From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew@dunslane.net>
cc: pgsql-hackers@lists.postgresql.org, pgbf@twiska.com
Subject: XversionUpgrade tests broken by postfix operator removal
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <449143.1600439950.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Fri, 18 Sep 2020 10:39:10 -0400
Message-ID: <449144.1600439950@sss.pgh.pa.us>
Precedence: bulk

Unsurprisingly, commit 1ed6b8956 has led to the buildfarm's
cross-version upgrade tests no longer working, eg

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dtadarida&dt=3D20=
20-09-18%2013%3A06%3A52

Checking for reg* data types in user tables                 ok
Checking for contrib/isn with bigint-passing mismatch       ok
Checking for user-defined postfix operators                 fatal
Your installation contains user-defined postfix operators, which are not
supported anymore.  Consider dropping the postfix operators and replacing
them with prefix operators or function calls.
A list of user-defined postfix operators is in the file:
    postfix_ops.txt

I intentionally let that happen, figuring that it'd be good to get some
buildfarm cycles on the new code in pg_upgrade that does this check.
But now we have to think about updating the test.  I think the best
bet is just to add some DROP OPERATOR commands to the existing
cleanup logic in TestUpgradeXversion.pm.  It looks like this would
do the trick:

drop operator #@# (bigint,NONE);
drop operator #%# (bigint,NONE);
drop operator !=3D- (bigint,NONE);
drop operator #@%# (bigint,NONE);

We could shorten this list a bit by changing create_operator.sql
in the back branches --- most of these have no particular reason
to be postfix rather than prefix operators.  I would not want to
remove them all, though, since that'd result in loss of test
coverage for postfix operators in the back branches.

			regards, tom lane