Wise monks,

Been a long time without posting here :^). I'm creating an RSS 2.0 feed. The code checks for new items from a forum and turns them into a proper XML file. We're planning to do this once an hour or so. Then I discovered that Google Reader (my RSS client) only polls the feed every three hours. This means that if I don't keep items between runs of the program, Google Reader will only catch the items posted to the forum in the last hour, so to avoid this I designed the following plan:

• Read previously saved items (XML chunks) into a hash and delete old ones. The hash key is each item's <title> tag, like in $h{$title} = $xml_chunk.
• Transform the original HTML into a set of RSS <item>s. Add them to the hash, overwriting those with the same <title> (these are new messages posted to an existing thread).
• Serialize the hash into a string of items (by just concatenating all elements).
• Save this string for later runs.
• Add the XML needed to change the string of <item>s into a real RSS feed (i.e. <rss>, <channel> and so on).

If you think there's a better way to approach this problem, please stop reading now ;^).

I'm getting a segmentation fault when extracting the title and the date from an item. This code triggers it:

#!/usr/bin/perl
## the version of XML::LibXML installed in the system is 1.63, so I tr
+ied installing 1.65 here:
BEGIN { unshift @INC, '/tmp/pm/lib/perl/5.8.8'; }
use warnings;
use strict;
use XML::LibXML;

print "Version: ", $XML::LibXML::VERSION, "\n";
my $parser = XML::LibXML->new;
my $item = $parser->parse_balanced_chunk (<<'EOT');
<item>
<title>Insert title here</title>
<link>http://foo/bar.html</link>
<description>Insert description here</description>
<guid isPermaLink="false">foobar@19700101:000000+0000</guid>
</item>
EOT
my $title = $item->findvalue ('//title');
print "Still alive!\n";
my $date = $item->findvalue ('//guid');
print "Still alive!\n";
print "got title ($title) and date ($date)\n";
[download]

$ ./foo.pl
Version: 1.65
Still alive!
Segmentation fault (core dumped)
[download]

I discovered this in a production system with libxml2 version 2.6.27, then I investigated it in my laptop with 2.6.30. Same result in both machines.

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