PostgreSQL 17: ERROR: commutator operator = is already the commutator of operator =

[df7cb]

rdkit is not compatible with PG 17 yet:

**** /tmp/autopkgtest.Rnc5Gt/tree/Code/PgSQL/rdkit/regression.diffs ****
diff -U3 /tmp/autopkgtest.Rnc5Gt/tree/Code/PgSQL/rdkit/expected/rdkit-91_1.out /tmp/autopkgtest.Rnc5Gt/tree/Code/PgSQL/rdkit/results/rdkit-91.out
--- /tmp/autopkgtest.Rnc5Gt/tree/Code/PgSQL/rdkit/expected/rdkit-91_1.out	2024-05-23 12:10:12.000000000 +0000
+++ /tmp/autopkgtest.Rnc5Gt/tree/Code/PgSQL/rdkit/results/rdkit-91.out	2024-05-23 13:22:31.278341481 +0000
@@ -4,181 +4,160 @@
 --
 SET client_min_messages = warning;
 \set ECHO none
+ERROR:  commutator operator = is already the commutator of operator =

See postgres/postgres@2b5154b

Full build/test log: https://pgdgbuild.dus.dg-i.net/job/rdkit-binaries-beta/architecture=amd64,distribution=sid/13/consoleText

[bjonnh-work]

CREATE OPERATOR @= (
    LEFTARG = mol,
    RIGHTARG = mol,
    PROCEDURE = mol_eq,
    COMMUTATOR = '=',
    NEGATOR = '<>',
    RESTRICT = eqsel,
    JOIN = eqjoinsel
);

This may be here. There are some issues with operators redefining commutators it seem:
https://www.postgresql.org/message-id/flat/ZTfL1G1fBPQHVPWV%40msg.df7cb.de#ce3801c084bcf05b6b976cb2d0e25b2d

Which seems to be what @= is doing trying to define itself as commutator to =.