Re: array_cat anycompatible change is breaking xversion upgrade tests

> On 24 Jun 2022, at 16:09, Andrey Borodin <x4mmm@yandex-team.ru> wrote:
>
> Would it be backpatchable to add this check to pg_upgrade?

Just to be clear of what exactly I propose I drafted a patch. PFA.
I've tested it with PG13 and
CREATE AGGREGATE public.array_accum(anyelement) (
     SFUNC = array_append,
     STYPE = anyarray,
     INITCOND = '{}',
     PARALLEL = safe
);
CREATE OPERATOR ##% (leftarg=anyarray, rightarg=anyelement,function=array_append);

Operator output currently look a bit strage, but does it's job. pg_upgrade_output.d/operators.txt:
In database: postgres
  (oid=16385) ##% in public

Thanks!

Best regards, Andrey Borodin.