Problem with Net::LDAP and $mesg->code

[fuser9bb]

I am using Net::LDAP (p5-perl-ldap-0.28) on a FreeBSD 4.9 server with Perl
5.8 (perl-5.8.2_5). In general, I have Net::LDAP working well, but every
once in a while I get an error. The problem is that I should never see this
error I think.

Here is what I do:

1. I connect to the LDAP server. I save this connection in a cache for reuse
later on.
2. I do a $mesg = ...search()
3. I verify that $mesg is defined.
4. I run $mesg->code.

Every once in a while I get this error message:

Can't call method "code" on an undefined value at xxx.pl

But I just verified that $mesg was defined! Why does this happen? And how
should I be checking for this kind of error?

Following is more or less the code I'm using. Any help is appreciated. Also,
before continuing, for debugging I tried to use Data::Dumper. The weird
thing is that I get no output whatsoever if my LDAP result has one or more
entries, but I do get debug output if I have no result set.

use Net::LDAP;
...
       if (defined $ldap_cache{"$rcpt_to_domain"}) {
               $ldap = $ldap_cache{"$rcpt_to_domain"};
       }
       else {
               my $ldap_port = 389;
               $ldap_port = $ldap_info->{"ldap_port"} if
(length($ldap_info->{"ldap_port"}) > 0);

               $ldap = Net::LDAP->new($ldap_info->{"ldap_server"},
                                       port => $ldap_port,
                                       timeout => 5,
                                       onerror=>'undef')
                       or die "Can't connect to
".$ldap_info->{"ldap_server"}.": $?";

               $ldap->bind($ldap_info->{"binddn"}, password =>
$ldap_info->{"bindpw"})
                       or die "Can't connect to
".$ldap_info->{"ldap_server"}.": $?";

               $ldap_cache{"$rcpt_to_domain"} = $ldap;
       }

       my $mesg = $ldap->search (  # perform a search
                              base   => $ldap_info->{"basedn"},
                              scope => "sub",
                              filter => $filter,
                              count => 1,
                              timeout => 5,
                             );

       if (! defined $mesg) {
               die "LDAP connection problem - temporary error - mail
requeue";
       }

       $mesg->code && die "$mesg->error";

(The last line is where I sometimes get a Perl error about an undefined
value.)

On a related note, I guess that my LDAP connection could die and so the
connection in my %ldap_cache would be wrong. Is there good way to detect if
this happens other than just doing a search() and waiting for an error?

For debugging I added this:

       if (! defined $mesg) {
               die "LDAP connection problem - temporary error - mail
requeue";
       }

       use Data::Dumper;
       my $mesg_dump = Dumper($mesg);
       `echo "$$ hi" >> /tmp/mesg_dump.txt`;
       `echo "$$ mesg_dump: $mesg_dump " >> /tmp/mesg_dump.txt`;
       `echo "$$ bye " >> /tmp/mesg_dump.txt`;

       $mesg->code && die "$mesg->error";

I only get:

$$ mesg_dump: ...

If I do an LDAP query for an entry that does not exists. Weird.