Serious Bug in latest Data::Dumper under 5.6.1

[demerphq]

Hi, this is just a heads up about a bug report I just filed to p5p and the maintainer of Data::Dumper. If you set $Data::Dumper::Sortkeys=1 and do not set $Data::Dumper::Useperl=1 under 5.6.1 (win32 at least) you will end up with either erroneous data or a segfault. If you set both at the same time this problem doesnt arise.

Note that this bug does not appear to affect 5.8.0 at all.

use Data::Dumper;
use strict;
use warnings;
$|++;
printf "D::D version %s\n",Data::Dumper->VERSION;
for my $sk (0,1) {
    print "\$Data::Dumper::Sortkeys=$sk\n";
    $Data::Dumper::Sortkeys=$sk;
    for my $up (1,0) {
        print "\$Data::Dumper::Useperl=$up\n";
        $Data::Dumper::Useperl=$up;
        my %rev;
        my %name;

        print "Dumper:\n",Dumper(\%rev,\%name),"\n";
    }
}
print "Done\n";
__END__
D::D version 2.121
$Data::Dumper::Sortkeys=0
$Data::Dumper::Useperl=1
Dumper:
$VAR1 = {};
$VAR2 = {};

$Data::Dumper::Useperl=0
Dumper:
$VAR1 = {};
$VAR2 = {};

$Data::Dumper::Sortkeys=1
$Data::Dumper::Useperl=1
Dumper:
$VAR1 = {};
$VAR2 = {};

$Data::Dumper::Useperl=0
Use of uninitialized value in print at c:\temp\test_dd.pl line 15.
Dumper:
$VAR2 = {};

I post this only as a public service, as I know many people here depend on DD in many ways, and this is a serious bug that is not picked up by the test suite.

Cheers,

[simonflk]

I get the segfault with perl 5.6.1 on solaris. But strangely, if I change the line:

    print "Dumper:\n",Dumper(\%rev,\%name),"\n";

to:

    my $dumped = Dumper(\%rev,\%name);
    print "Dumper:\n",$dumped,"\n";

It works fine. I can't see why that should make any difference.

Update:

simonf$ perl -MData::Dumper -le 'print Data::Dumper->VERSION'
2.12_01

Update: Tested on Win32, with ActiveState's D::D 2.121 PPM. Same behaviour - using Dumper() in scalar context avoids segfault.

[IlyaM]

Similar problem can be reproduced on perl 5.8.0 too. Minimal test case:

use Data::Dumper;
$Data::Dumper::Sortkeys = sub { [ sort keys %{$_[0]} ] };
print Dumper({}, {});