Can't edit an array value in closure

Question

Hey, I'm not quite sure if it is a bug or just a feature change:

$a = array(array(0));

array_walk(
    $a,
    function (&$e) {
        array_filter(array(), function() use ($e) {});
        $e[] = 1;
    }
);

print_r($a[0]);

in PHP 5.5.3-1ubuntu2.3 returns

Array
(
    [0] => 0
    [1] => 1
)

and in PHP 5.3.3-7+squeeze19

Array
(
    [0] => 0
)

Answer 1

This issue with the same variable being used repeatedly in closures, sometimes by reference, sometimes by value was a known bug in versions of PHP up to 5.3.5. PHP 5.3.6 attempted to fix the issue, but introduced a new bug in doing so. The problem was finally resolved in PHP 5.3.7