Custom comment action

Question

I have updated my Wordpress version from 4.3.1 to 4.5.2 and apparently it broke a custom function I've made in the past.
What it does: Display a anchor below comments, next to Approve/Answer/Edit/Spam/Delete in the backend. On anchor click it does redirect me to "wp-admin/cust_comment.php?c=ID&action=(un)highlightcomment&_wpnonce=HASH". From this point it should update the comments meta_key "highlight" to 1 or 0. But instead all I'm receiving is a blank page.

cust_comment.php

custom "wp-admin/comment.php"

<?php
require_once( dirname( __FILE__ ) . '/admin.php' );
wp_reset_vars( array('action') );
$comment_id = absint( $_GET['c'] );

switch( $action ) {

    case 'highlightcomment'    :
    case 'unhighlightcomment'  :

        $noredir = isset($_REQUEST['noredir']);

        if ( !$comment = get_comment($comment_id) )
            comment_footer_die( __( 'Invalid comment ID.' ) . sprintf(' <a href="%s">' . __('Go back') . '</a>.', 'edit-comments.php') );
        if ( !current_user_can( 'edit_comment', $comment->comment_ID ) )
            comment_footer_die( __('You are not allowed to edit comments on this post.') );

        if ( '' != wp_get_referer() && ! $noredir && false === strpos(wp_get_referer(), 'comment.php') )
            $redir = wp_get_referer();
        elseif ( '' != wp_get_original_referer() && ! $noredir )
            $redir = wp_get_original_referer();
        elseif ( in_array( $action, array( 'highlightcomment', 'unhighlightcomment' ) ) )
            $redir = admin_url('edit-comments.php?p=' . absint( $comment->comment_post_ID ) );
        else
            $redir = admin_url('edit-comments.php');

        $redir = remove_query_arg( array('highlighted', 'unhighlighted'), $redir );

        switch ($action) {

            case 'highlightcomment' :
                update_comment_meta($comment_id, 'highlight', 1);
                $redir = add_query_arg( array('highlighted' => '1'), $redir );
                break;

            case 'unhighlightcomment' :
                update_comment_meta($comment_id, 'highlight', 0);
                $redir = add_query_arg( array('unhighlighted' => '1'), $redir );
                break;
        }

        wp_redirect( $redir );
        die;

        break;

    default:
        wp_die( __('Unknown action.') );

} // end switch

functions.php

add_filter('comment_row_actions', 'cust_hightlight_comment_action', 10, 2);
function cust_hightlight_comment_action($actions, $comment) {

    $highlight_nonce = esc_html( '_wpnonce=' . wp_create_nonce( "approve-comment_$comment->comment_ID" ) );

    $url = "cust_comment.php?c=$comment->comment_ID";
    $highlight_url =  $url . "&action=highlightcomment&$highlight_nonce";
    $unhighlight_url = $url . "&action=unhighlightcomment&$highlight_nonce";

    if (!get_comment_meta( $comment->comment_ID, 'highlight', true) )
        $actions['highlighter'] = "<a href='$highlight_url' class='vim-a'>" . _x( 'Highlight' ) . '</a>';
    else
        $actions['unhighlighter'] = "<a href='$unhighlight_url' class='vim-u'>" . _x( 'Don\'t highlight') . '</a>';

    return $actions;
}

Answer 1

I've found the source of the problem, I have redeclared the function comment_footer_die(). Which wordpress obviously can't accept. My supplied code works as intended.