Hi,
I think that commit f0d65c0
<https://github.com/postgres/postgres/commit/f0d65c0eaf05d6acd3ae05cde4a31465eb3992b2>
has an oversight.
Attnum == 0, is system column too, right?
All other places at tablecmds.c, has this test:
if (attnum <= 0)
ereport(ERROR,
regards,
Ranier Vilela