Re: plperl: sort trapped by operation mask

On Wed, 2005-10-05 at 18:11 -0700, David Fetter wrote:

> It's untrusted in the context of s///e.

...

> my $NOT_RIGHT_BRACKET = qr([^\\]]+); # parse as regex 1st.
> s@
> \\[($NOT_RIGHT_BRACKET)\\]
> @
> "[" .
> join("", sort {$a cmp $b} (split(//, $1)) ) .
> "]"
> @egmx;

David-

Kudos for digesting (and cleaning up) my obfuscated perl.

The code is intended to sort tokens within [] sets in a regexp. My
primary motivation is a canonical form for such regexps. For example, I
want A[BCBB][DEE] to become A[BC][DE]. The sort is required to get the
canonical ordering within []. (David's code is close to equivalent, but
without hashing tokens inside [], it won't compress multiple instances
of the same token.)

The problem is that sort apparently requires an untrusted language.
Example:

=> create or replace function sort_test() returns text
strict immutable language plperl as '
my @x = qw(c b a);
return join("",sort @x);
';

=> select sort_test();
ERROR: creation of function failed: 'sort' trapped by operation mask at (eval 10) line 3.

The same function defined with plperlu (untrusted) works fine.

Surely I'm not the first one to try sort in a plperl function. And I
can't think of any reason for sort to require a trusted language.

I don't see anything specifically about sort and plperl/plperlu on the
web. Enlightenment, anyone?

Thanks,
Reece

--
Reece Hart, http://harts.net/reece/, GPG:0x25EC91A0