Re: pgsql: libpq: Grease the protocol by default

Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com> writes:
> Oh, the envvar is clever. You'll probably want to do that only for the
> pg_dumpall invocation now that pg_upgrade is patched, though, so we
> don't cover up regressions.

I can confirm clean x-version tests on all branches with git tip
and this:

--- TestUpgradeXversion.pm.orig 2025-11-25 07:47:25.000000000 -0500
+++ TestUpgradeXversion.pm 2026-02-24 18:50:29.487530840 -0500
@@ -485,10 +485,14 @@ sub test_upgrade ## no critic (Subrou

# use the NEW pg_dumpall so we're comparing apples with apples.
setinstenv($self, "$installdir", $save_env);
+ local $ENV{PGMAXPROTOCOLVERSION} =
+ ($oversion le 'REL9_2_STABLE') ? "3.0" : "latest";
+
system( qq{"$installdir/bin/pg_dumpall" $dump_opts -p $sport -f }
. qq{"$upgrade_loc/origin-$oversion.sql" }
. qq{> "$upgrade_loc/$oversion-dump1.log" 2>&1});
return if $?;
+ delete $ENV{PGMAXPROTOCOLVERSION};
setinstenv($self, "$other_branch/inst", $save_env);

system( qq{"$other_branch/inst/bin/pg_ctl" -D }

which is Andrew's patch but with the envvar dropped as soon
as possible.

regards, tom lane