Description:
------------
I'm not sure is a bug but I don't understand why the first block is executed correctly whereas the second one (same code) returns with this warning:

Warning: array_multisort() [function.array-multisort]: Array sizes are inconsistent in /usr/local/httpd-2.2.0/htdocs/test/multisort.php on line 27

Reproduce code:
---------------
<?
error_reporting(E_ALL);

// first block 
$data = array();

$data[2] = array('volume' => 67, 'edition' => 2);
$data[3] = array('volume' => 86, 'edition' => 1);

foreach ($data as $key => $row) {
   $volume[$key]  = $row['volume'];
   $edition[$key] = $row['edition'];
}

array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data);

// second block (equal to first block)
$data = array();

$data[2] = array('volume' => 67, 'edition' => 2);
$data[3] = array('volume' => 86, 'edition' => 1);

foreach ($data as $key => $row) {
   $volume[$key]  = $row['volume'];
   $edition[$key] = $row['edition'];
}

array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data);

?>

Expected result:
----------------
Both blocks give the same result.




Actual result:
--------------
Warning: array_multisort() [function.array-multisort]: Array sizes are inconsistent in /usr/local/httpd-2.2.0/htdocs/test/multisort.php on line 27