zengargoyle nailed your problem down, but I played around a bit to reproduce your problem and have some extra information that might interest you. Specifically, the reason you get lots of references to $output->[1] in your last dump is that Data::Dumper does not do deepcopies by default: if it encounters array elements that point to the same thing, it prints a self-reference (hence $output->[1]). You can control this behaviour with $Data::Dumper::Deepcopy. E.g. 
use strict;
use Data::Dumper;
my $hashref= { 'one' => 'two' };
my $aryref=[ $hashref ];
push @$aryref, $hashref;
push @$aryref, $hashref;
print "Without Deepcopy: ".Dumper($aryref);
$Data::Dumper::Deepcopy=1;
print "With Deepcopy: ".Dumper($aryref);
print "Without Data::Dumper:\n";
print join("\n", @$aryref);
__END__
Without Deepcopy: $VAR1 = [
          {
            'one' => 'two'
          },
          $VAR1->[0],
          $VAR1->[0]
        ];
With Deepcopy: $VAR1 = [
          {
            'one' => 'two'
          },
          {
            'one' => 'two'
          },
          {
            'one' => 'two'
          }
        ];
Without Data::Dumper:
HASH(0x8111a94)
HASH(0x8111a94)
HASH(0x8111a94)

[download]
So, the weird stuff you saw was actually a Data::Dumper artifact. There are actually three identical references in the array, but Data::Dumper only derefs one by default.

Anyway, we now return you to the scheduled programme.

CU
Robartes-

In reply to Re: Push corrupting data by robartes
in thread Push corrupting data by Tanalis

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