Re: BUG #17480: Assertion failure in parse_relation.c

Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> and with this it is clear that the problem is that the alias list is too
> long for the COLUMNS specification of the XMLTABLE function.

Check.

> This can be avoided by throwing an error:

+1, but you should match the ERRCODE thrown by buildRelationAliases,
that is ERRCODE_INVALID_COLUMN_REFERENCE.

Looking at the other addRangeTableEntry* functions,
addRangeTableEntryForJoin seems to similarly lack a defense
against too many aliases. Testing shows that the case is covered
elsewhere:

regression=# select * from (int8_tbl i cross join int4_tbl j) ss(a,b,c,d) limit 2;
ERROR: column alias list for "ss" has too many entries
regression=# \errverbose
ERROR: 42601: column alias list for "ss" has too many entries
LOCATION: transformFromClauseItem, parse_clause.c:1458

but this is randomly different both in the message wording and in the
choice of ERRCODE. I wonder if we shouldn't harmonize that, and maybe
move detection of the case to addRangeTableEntryForJoin for consistency
with the other cases.

regards, tom lane