for some reason $r_url was empty and parse_url func was breaking on that. so I had to add an extra check in the below function

<?php
function _feeds_tamper_absolute_url($r_url, &$urls, $b) {
  if(empty(
$r_url)){
    return;
  }
 
$r = parse_url($r_url);
?>

Comments

also I had to do this to handle images in google news rss feeds https://news.google.com/news/feeds?output=rss&q=%22rti%20act%22
description has //nt3.ggpht.com/news/tbn/b0UpRelFgmEtpM/6.jpg
which has to be converted to https://nt3.ggpht.com/news/tbn/b0UpRelFgmEtpM/6.jpg

<?php
if(substr($r_url,0,2)=="//"){
   
$r_url = "http:".$r_url;
  }
?>

Status:Active» Postponed (maintainer needs more info)

What was your configuration that gave you an empty value?

Breaking how, there's already a check to see if the parse failed?

  if ($r == FALSE) {
    return;
  }

Handling scheme relative urls would be a different issue.