An example of the problem is viewable on my brand new sandbox blog @ http://www.village-idiot.org/test-install/?p=1#comments
That is a brand new install with NO plugins installed.
Essentially what is happening is that link is being filtered twice and content is being added to the comment.
When you view the source for the second comment, you will notice that nofollow tags are changed - thats because I edited the make_clickable function and the wp_rel_nofollow function:
function wp_rel_nofollow( $text ) {
$text = preg_replace('|<a (.+?)>|i', '<a $1 rel="nofollow-function">', $text);
return $text;
}
function make_clickable($ret) {
$ret = ' ' . $ret . ' ';
$ret = preg_replace("#([\s>])(https?)://([^\s<>{}()]+[^\s.,<>{}()])#i", "$1<a href='$2://$3' rel='nofollow-clickable'>$2://$3</a>", $ret);
$ret = preg_replace("#(\s)www\.([a-z0-9\-]+)\.([a-z0-9\-.\~]+)((?:/[^ <>{}()\n\r]*[^., <>{}()\n\r]?)?)#i", "$1<a href='http://www.$2.$3$4' rel='nofollow-clickable'>www.$2.$3$4</a>", $ret);
$ret = preg_replace("#(\s)([a-z0-9\-_.]+)@([a-z0-9\-_.]+)\.([^,< \n\r]+)#i", "$1<a href=\"mailto:$2@$3.$4\">$2@$3.$4</a>", $ret);
$ret = trim($ret);
return $ret;
}
Now the source for the link in question:
<a href="http://www.test.com" rel="nofollow-function"><a href='http://www.test.com' rel='nofollow-clickable'>http://www.test.com</a></a>
the comment I submitted was:
<a href="http://www.test.com">http://www.test.com</a>
Obviously thats not correct.