XML::Twig - bug or something else?

GrandFather has asked for the wisdom of the Perl Monks concerning the following question:

In playing around with code for a recent SoPW answer I got distracted by what seems to be a bug in XML::Twig. I updated to the current version and the problem seems to have changed somewhat (the "answer" code now works if a flush is removed), but there seems to be a related error:

use strict;
use warnings;
use XML::Twig;

my $org = <<XML;
<XXX>
</XXX>
XML

print "XML::Twig version $XML::Twig::VERSION\n";

my $twig = XML::Twig->new (
    twig_roots               => {'head' => \&editNode,},
    twig_print_outside_roots => 1
);

$twig->parse ($org);
$twig->flush ();


sub editNode {
    my ($t, $elt) = @_;

    $t->flush      ();
}
[download]

Prints:

XML::Twig version 3.32
<XXX>
</XXX>
</XXX>
[download]

Note the duplicated close tag. Removing the flush after the parse fixes the problem, but the documentation and samples mention in several places that it should be there.

Is it a bug? Should I report it?

Update reported as rt://39848.

Perl reduces RSI - it saves typing

Comment on XML::Twig - bug or something else? Select or Download Code

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Re: XML::Twig - bug or something else? by mirod (Canon) on Oct 07, 2008 at 11:20 UTC
It's a bug: when the root triggers are never activated, then the root end tag gets output twice. It's caused by the new code that makes the final `flush` optional (as long as `flush` has been called at least once during parsing). It seemed to be a common mistake, so I tried preventing it from happening. The development version on the XML::Twig site is fixed (but I haven't added a test yet).	[reply]
Re: XML::Twig - bug or something else? by dHarry (Abbot) on Oct 07, 2008 at 07:25 UTC
I don’t think it’s a bug, is it? I encountered something similar, see for example Putting XML::Twig to the test. I did some performance tests with XML::Twig using different approaches and also ran into similar things. Normally I blame my code. As is said in the online tutorial: Note: as of XML::Twig 3.23, there is no longer any need to call `flush` one last time after the document is completely parsed. If the document was flushed, then it will be "auto-flushed" (to the same filehandle used for the first flush) after the parse. Maybe the man can shine his light on this one? cheers dHarry	[reply] [d/l]
Re: XML::Twig - bug or something else? by Anonymous Monk on Oct 07, 2008 at 00:47 UTC
Is it a bug? Should I report it? yes and yes	[reply]