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

From: oriol dot gual at gmail dot com Operating system: Windows XP SP2 PHP version: 5.2.1 PHP Bug Type: Session related Bug description: Multiple intances of a singleton class when stored in session 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 bug report at http://bugs.php.net/?id=40968&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=40968&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=40968&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=40968&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=40968&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=40968&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=40968&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=40968&r=needscript Try newer version: http://bugs.php.net/fix.php?id=40968&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=40968&r=support Expected behavior: http://bugs.php.net/fix.php?id=40968&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=40968&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=40968&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=40968&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=40968&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=40968&r=dst IIS Stability: http://bugs.php.net/fix.php?id=40968&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=40968&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=40968&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=40968&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=40968&r=mysqlcfg