Warnings generated with PHP <5.3.3

Despite the thrown warning, does the function behave correctly otherwise (returning FALSE with an illegit string)? I don't have easy access to 5.3.2 to test with.

Thank you. I think I'd rather implement a wrapper around parse_url() which uses try/catch instead of using the hacky @ operator, as your patch does. But that should be an easy fix. Fortunately, it appears that D8 will require at least PHP 5.3.5, so I'll only need to implement this workaround in the D7 branch.

I'd rather implement a wrapper around parse_url() which uses try/catch instead of using the hacky @ operator

Derp, that won't work - a warning is not an exception, and can't be "caught" that way.

Okay, I made a commit that uses @ before all parse_url() calls (along with a comment stating I do not wish to be judged by it :P ). Could you have a look when the next development release is available and let me know if it works for you?

I am judging you by it :P
If anything, suppress errors on less than 5.3.3 explicitly via a small utility function

eg.

/**
 * Custom parse URL function which suppresses warnings on PHP less 
 * than 5.3.3
 * See https://drupal.org/node/2104849
 */
function pathologic_parse_url($url, $component = NULL) {
  // surpress all errors to hide warnings :(
  if (version_compare(PHP_VERSION, '5.3.3') < 0) {
    return @parse_url($url, $component);
  }
  return parse_url($url, $component);
}

I'm pretty far from convinced that that method is better than what we've got now…