PHP Bug Warning: uksort(): Array was modified by the user comparison function

uksort.php

<?php
/**
 * The following will produce this result:
 * 
 * Warning: uksort(): Array was modified by the user comparison function in /Users/kento/Sites/uksort.php on line 12
 * set = array ( 'apple' => 'green', 'color' => 'yellow', 'wine' => 'white', 'yoghurt' => 'frozen', )
 * 
 * See also https://bugs.php.net/bug.php?id=50688
 **/

ini_set( 'display_errors', 1 );

$set = array( 'color' => 'yellow', 'apple' => 'green', 'yoghurt' => 'frozen', 'wine' => 'white' );

function foo( $a, $b ) {
        new Exception();
        return strcmp( $a, $b );
}

uksort( $set, 'foo' );
echo ' set = ' . var_export( $set,true );