Here's a test case:

XML file:

<?xml version="1.1"?>
<a xmlns="default_ns_top">
        <b xmlns:foo="foo"/>
        <c xmlns:bar="bar"/>
        <d xmlns:baz="baz">
                <e xmlns:lala="lala" xmlns:baz="baz2" xmlns="default_ns"/>
        </d>
</a>

a test perl script:

use strict;
use warnings;
use Data::Dumper;
use XML::Twig;

my $twig=XML::Twig->new();
$twig->xparse(shift);

traverse($twig->root);


sub traverse {
        my ($t) = @_;
        print "gi=|",$t->gi,"|\tprefix=|",$t->ns_prefix,"|\tnamespace=|",$t->namespace,"|\n";
        foreach my $c ($t->children) {
                if (@ARGV) {
                        my $copy = $c->copy;
                        traverse($copy);
                } else {
                        traverse($c);
                }
        }
}

Notice the output when you run:

$ perl test.pl test.xml # this is behaving OK

But when you run it with a copy:

$ perl test.pl test.xml copy # this is not OK

You don't see a lot of namespace information.

I'm going to try and use your proposed workaround.

Thanks for your help.