Re: Bug/unpredictable behavior in Schema.pm for must/may methods

[Graham Barr]

On 25 Sep 2003, at 19:04, Matthias Helmling wrote:
Hi,

here's the part of code ($VERSION = "0.9901") from
the Schema.pm Module which i just downloaded from
theoryx5.uwinnipeg.ca/CPAN/data/perl-ldap/.
---------- [snipp] ------------------------

  while (@oc) {
    my $oc = shift @oc;
    $done{lc $oc}++ and next;

    my $elem = $self->objectclass( $oc ) or next;
    my $res  = $elem->{$must_or_may} or next;
    @res{ @$res } = ();         # Add in, getting uniqueness
That is a bug, it should be

  if (my $res = $elem->{$must_or_may}) {
    @res{ @$res } = ();         # Add in, getting uniqueness
  }
so that it does continue to follow the sup chain

Graham.

    my $sup = $elem->{sup} or next;
    push @oc, @$sup;
  }
  my %unique = map { ($_,$_) } $self->attribute(keys %res);
  values %unique;
}
---------- [snipp] ------------------------

The loop iterates over all the super objectClasses for an object
(at least thats what i suggest it's supposed to do).
If an objectClass does NOT contain eihter a must or may entry
the super class is simply ignored
my $res  = $elem->{$must_or_may} or next;

while the must or may of the super class are taken into account
if they are already in the objectClass just inspected.
eg.

class A:
  must: a, b
  may:  c, d
class B:
  super of class A
  must:
  may: e, f
than may(B)  returns (c,d,e,f)
     must(B) returns ()
Cheers,

Matthias Helmling

--
Matthias Helmling                  System Administration
LION bioscience AG,                Waldhofer Str. 98, D-69123 
Heidelberg