Why can't Win32::TieRegistry list subkeys?

Question

Using Cygwin Perl v5.8.8 and Win32::TieRegistry 0.26.

We can get a tied hash object thing for HKEY_CURRENT_USER:

$ perl -e '
my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER"};
print Dumper $Key;'
$VAR1 = bless( {}, 'Win32::TieRegistry' );

And this works for sub keys:

$ perl -e '
my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER\\Software"};
print Dumper $Key;'
$VAR1 = bless( {}, 'Win32::TieRegistry' );

And we can print information for the key:

$ perl -e '
my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER\\Software"};
print Dumper $Key->Information;'
$VAR1 = 'CntSubKeys';
$VAR2 = 48;
$VAR3 = 'MaxSubClassLen';
$VAR4 = 21;
...

However the documentation implies we can list the sub keys simply by treating it as a hash:

$ perl -e '
my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER\\Software"};
print Dumper keys %$Key; '

But the array is empty. Is it broken or am I doing something wrong? Is there another way to list the sub keys?

This doesn't work either:

$ perl -e '
my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER\\Software"};
print Dumper $Key->SubKeyNames;'
Can't use an undefined value as an ARRAY reference at
/usr/lib/perl5/vendor_perl/5.8/cygwin/Win32/TieRegistry.pm line 720.

Answer 1

With your code:

my %RegHash;
use Win32::TieRegistry( TiedHash => \%RegHash );
use Data::Dumper;
my $Key = $RegHash{"HKEY_CURRENT_USER\\Software"};
print Dumper keys %$Key;

I get this result on my machine (WinXP, ActiveState Perl v5.10.0, Win32-TieRegistry 0.25):

$VAR1 = 'Adobe\\';
...
$VAR101 = 'Classes\\';
$VAR102 = '\\';

and this is what I get with your second code sample:

$VAR1 = 'Adobe';
...
$VAR101 = 'Classes';

So both of your code samples work okay, on ActiveState Perl and Windows XP at least.

EDIT: This looks like a more general problem/bug:

• TieRegistry module fails to enumerate values on community.activestate.com
• Win32::TieRegistry Error (or is it me?) on prlmnks.org
• a blog post on weblog.siliconcerebrate.com
• the whole thing seems to be related to Windows Vista