Description:
------------
I'm developing an app which uses storage with fairly large amount of objects that are created from unserialized cached data.

Objects properties are set by iterating through get_object_vars() which causes extremely high memory usage.

Provided is reduced test case for reproducing this issue. The difference between two create functions is only the amount of get_object_vars() calls which leads me to conclusion it's a memory leak.

Results are:
Create(): Memory usage: 28.72MB
CreateWithLeak(): Memory usage: 95.1MB

Test script:
---------------
abstract class ObjectVarsCache
{
    public static $vars = array();
}

class Test
{
    public $a;
    public $b;
    public $c;
    public $d;
    public $e;
    public $f;
    public $g;
    public $h;
    public $i;
    public $j;

    public function CreateWithLeak()
    {
        $vars = get_object_vars($this);
    }

    public function Create()
    {
        $vars = &ObjectVarsCache::$vars;
        if (!$vars)
            $vars = get_object_vars($this);
    }
}

$objects = array();

for ($i = 0; $i < 100000; ++$i)
{
    $object = new Test;
    //$object->Create(); // uncomment to compare
    $object->CreateWithLeak();

    $objects []= $object;
}

echo "Memory usage: ".round(memory_get_usage() / 1024 / 1024, 2)."MB, Peak memory usage: ".round(memory_get_peak_usage() / 1024 / 1024, 2)."MB";