#32322 [Opn->Csd]: Return values by reference broken( using self::),example singleton instance
| From: | dmitry@php.net | Date: | Wed, 08 Jun 2005 08:44:12 +0000 |
| Subject: | #32322 [Opn->Csd]: Return values by reference broken( using self::),example singleton instance | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-80034@lists.php.net to get a copy of this message | ||
ID: 32322
Updated by: dmitry@php.net
Reported By: rickd at commando-pernod dot net
-Status: Open
+Status: Closed
Bug Type: Zend Engine 2 problem
Operating System: Win2000
PHP Version: 5CVS-2005-03-19
New Comment:
This bug is already fixed in CVS HEAD and PHP_5_0.
Previous Comments:
------------------------------------------------------------------------
[2005-03-20 06:07:13] rickd at commando-pernod dot net
<?php
class test
{
private static $instance = null;
private $myname = '';
private function __construct( $value = '' )
{
echo "New class $value created \n";
$this -> myname = $value;
}
private function __clone() {}
static public function getInstance()
{
if ( self::$instance == null )
{
self::$instance = new test('Singleton1');
}
else {
echo "Using old class " . self::$instance -> myname .
"\n";
}
return self::$instance;
}
static public function getInstance2()
{
static $instance2 = null;
if ( $instance2 == null )
{
$instance2 = new test('Singleton2');
}
else {
echo "Using old class " . $instance2 -> myname . "\n";
}
return $instance2;
}
public function __destruct()
{
if ( defined('SCRIPT_END') )
{
echo "Class " . $this -> myname . " destroyed at script end
\n";
} else {
echo "Class " . $this -> myname . " destroyed beforce
script end \n";
}
}
}
echo "Try static instance inside class :\n";
$getCopyofSingleton = test::getInstance();
$getCopyofSingleton = null;
$getCopyofSingleton = &test::getInstance();
$getCopyofSingleton = null;
$getCopyofSingleton = test::getInstance();
echo "Try static instance inside function :\n";
$getCopyofSingleton2 = test::getInstance2();
$getCopyofSingleton2 = null;
$getCopyofSingleton2 = &test::getInstance2();
$getCopyofSingleton2 = null;
$getCopyofSingleton2 = test::getInstance2();
define('SCRIPT_END',1);
?>
Current result :
Try static instance inside class :
New class Singleton1 created
Using old class Singleton1
Class Singleton1 destroyed beforce script end
New class Singleton1 created
Try static instance inside function :
New class Singleton2 created
Using old class Singleton2
Using old class Singleton2
Class Singleton1 destroyed at script end
Class Singleton2 destroyed at script end
Expected result :
Try static instance inside class :
New class Singleton1 created
Using old class Singleton1
Using old class Singleton1
Try static instance inside function :
New class Singleton2 created
Using old class Singleton2
Using old class Singleton2
Class Singleton1 destroyed at script end
Class Singleton2 destroyed at script end
php setting :
allow_call_time_pass_reference Off Off
zend.ze1_compatibility_mode Off Off
What i mean whats going wrong :
to return a variable by reference, you need to define the caller´s code
and function code with a & prefix, but it seems when you use the self::
and parent:: as return values
this is broken, only caller need a & prefix, that is what i mean
------------------------------------------------------------------------
[2005-03-19 21:49:04] sniper@php.net
Please provide an example script that actually returns something. And
give the expected / actual results too.
------------------------------------------------------------------------
[2005-03-15 19:54:01] rickd at commando-pernod dot net
Description:
------------
We use a user singleton instance for our cms user authed ids that
should not be able to killed from third party addons or worse coders so
easily, but accessable from all.
But when someone get the instance with reference it can be killed easy
with setting the reference var to null, unset dont work.
If you put the static $instance holder inside the getinstance()
function it seems to be work correct and cant be deleted from setting
reference to NULL
Reproduce code:
---------------
class test {
static private $instance = null;
static function getinstance() {
if ( self::$instance == null ) {
return new test();
}
return self::$instance;
}
}
$user = &test::getinstance();
$user = null; // destroy singleton instance
$user = &test::getinstance();
unset( $user ); // dont destroy instance
Expected result:
----------------
singleton not destroying with setting a getted instance with
reference to null
Actual result:
--------------
singleton destroyed
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=32322&edit=1