WSOD due to infinite recursion

added a dirty debug line to that function:

/**
* Specialized Array Data Comparision Code
*/
function drupalforfirebug_array_compare_code($a, $b, $c = array(), $history = array()) {
  error_log(print_r(get_defined_vars(),1));

and squeezed out the input that brought the function to that infinite loop:

Array
(
    [a] => 
    [b] => Array
        (
            [js] => Array
                (
                    [0] => modules/menu/menu.js
                )

            [library] => Array
                (
                    [0] => Array
                        (
                            [0] => system
                            [1] => drupal.form
                        )

                    [1] => Array
                        (
                            [0] => system
                            [1] => drupal.collapse
                        )

                )

        )

    [c] => Array
        (
            [js] => Array
                (
                    [0] => modules/menu/menu.js
                )

            [library] => Array
                (
                    [0] => Array
                        (
                            [0] => system
                            [1] => drupal.form
                        )

                    [1] => Array
                        (
                            [0] => system
                            [1] => drupal.collapse
                        )

                )

        )

    [history] => Array
        (
        )

)

tralala, found a commit that removed recursion conditions: 14b2bdb109e9337063d45a8cd805a842c23e045b

reverted that part an voila it goes!