Edit report at https://bugs.php.net/bug.php?id=52318&edit=1

 ID:                 52318
 Comment by:         landeholm at gmail dot com
 Reported by:        brendel at krumedia dot de
 Summary:            Weak references for PHP
 Status:             Open
 Type:               Feature/Change Request
 Package:            Scripting Engine problem
 PHP Version:        Irrelevant
 Block user comment: N
 Private report:     N

 New Comment:

I just ran into this issue again... Please make PHP a modern language and 
implement this already.


Previous Comments:
------------------------------------------------------------------------
[2010-08-09 10:17:09] brendel at krumedia dot de

bastard dot internets at gmail dot com,

for framework developers this would be very useful. It just means, when the 
user of the framework no longer use a certain object the framework also should 
not longer waste memory. There are no pitfalls for the user. But the framework 
is more flexible.

------------------------------------------------------------------------
[2010-08-09 08:57:46] bastard dot internets at gmail dot com

brendel at krumedia dot de - Good call:  "$user now contains a new user object"

When looking at it from a security perspective, I do believe you just killed 
all my arguments against.  Not because you've proven it impossible, but because 
unless the developer explicitly wants that functionality, their code will have 
a thousand holes.

------------------------------------------------------------------------
[2010-08-09 08:21:48] brendel at krumedia dot de

Hi bastard dot internets at gmail dot com,

see how variable references are no solution:

<?php
$repository = new SplWeakArrayValues();

$user = $dbTable->getUserById(1);
$repository[$user->id] = $user;

// Now two variables hold object references to one user object

$user = new User();

// $user now contains a new user object and the old one should have
// been removed from the repository. This time i do not assign null
// but another (transient) user object.
// count($repository) should equal 0.

?>

------------------------------------------------------------------------
[2010-08-09 08:08:26] bastard dot internets at gmail dot com

brendel at krumedia dot de - You got me at "Also count($repository) should 
equal 0"

As I said earlier, "Registry::$Collection[$a->id] = null;" will set all 
variables referring to this object handle to null globally.  However, 
count(Registry::$Collection) is still 1.

I'd still argue this is possible using existing language features.  However, it 
means juggling so many references, forced implementing spaghetti code to get a 
solution, and a single missing "&" symbol anywhere leading to hours of 
debugging.  And, I just found myself needing just such a solution.

So, I'd have to vote for a built-in interface or class like you describe.

------------------------------------------------------------------------
[2010-08-03 16:43:39] brendel at krumedia dot de

Sample code use case:

<?php
$repository = new SplWeakArrayValues(); // assume it implements
                                      // ArrayAccess and others

$user = $this->userObjectFromSomewhere();
$repository[$user->id] = $user;

// Now two variables hold object references to one user object

$user = null;

// Since $repository is weak, the destructor of the class of $user should have 
been called now
// Also count($repository) should equal 0

?>

------------------------------------------------------------------------


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    https://bugs.php.net/bug.php?id=52318


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