PG Bug reporting form <noreply@postgresql.org> writes:
> accidentally I tried to change a system column data type on Windows and got
> a strange error message "no owned sequence found":
> postgres=# alter table t1 alter column cmin type text;
> ERROR: no owned sequence found
> postgres=# alter table t1 alter column cmax type text;
> ERROR: cannot alter system column "cmax"
Yeah, same here.
> I think the ATParseTransformCmd() function needs the same check as the check
> in the ATPrepAlterColumnType() function.
That seems pretty duplicative. I think it's sufficient to do something
like
- if (TupleDescAttr(tupdesc, attnum - 1)->attidentity)
+ if (attnum > 0 &&
+ TupleDescAttr(tupdesc, attnum - 1)->attidentity)
in the faulty code, and let the actual error message come out where
it does now.
Will fix, thanks for the report!
regards, tom lane