#40968 [Com]: Multiple intances of a singleton class when stored in session

ID: 40968 Comment by: b dot fore at mail dot com Reported By: oriol dot gual at gmail dot com Status: Open Bug Type: Session related Operating System: Windows XP SP2 PHP Version: 5.2.1 New Comment: That's a gross abuse of ext/session dude. Previous Comments: ------------------------------------------------------------------------ [2007-03-31 16:54:52] oriol dot gual at gmail dot com Description: ------------ When storing an object of a singleton class in the session, you can have more than one instance of that class in other subsequent executions. Reproduce code: --------------- class Singleton { private static $instance; private function __construct() {} final public static function getInstance() { if (!isset(Singleton::$instance)) { Singleton::$instance = &new Singleton; } return Singleton::$instance; } } session_start(); if(!isset($_SESSION['singleton'])) $_SESSION['singleton'] = Singleton::getInstance(); $test = Singleton::getInstance(); $anotherTest = Singleton::getInstance(); var_dump(Singleton::getInstance() === $test); var_dump(Singleton::getInstance() === $anotherTest); var_dump($test === $anotherTest); var_dump(Singleton::getInstance() === $_SESSION['singleton']); var_dump($test === $_SESSION['singleton']); var_dump($anotherTest === $_SESSION['singleton']); session_write_close(); Expected result: ---------------- Session not started (first execution) bool(true) bool(true) bool(true) bool(true) bool(true) bool(true) Subsequent executions bool(true) bool(true) bool(true) bool(true) bool(true) bool(true) Actual result: -------------- Session not started (first execution it's OK) bool(true) bool(true) bool(true) bool(true) bool(true) bool(true) Subsequent executions (fails, multiple instances) bool(true) bool(true) bool(true) bool(false) bool(false) bool(false) ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=40968&edit=1