From: k at phpkoala dot com
Operating system: Linux
PHP version: 5.1.2
PHP Bug Type: Class/Object related
Bug description: unset() no longer works on $this in PHP5
Description:
------------
In PHP4, calling unset($this) within a class worked fine, and destroyed
that class instance. This was a very useful way technique, one that I and
others have used many times.
In PHP5, it simply no longer works. There is no error message - not even a
strict - the instance is just unaffected.
PHP4 also offers another method - setting $this = NULL, but PHP5 gives an
error that $this cannot be reassigned.
I would like to see this functionality restored, or, an alternate
mechanism for destroying class instances internally should be pointed out
(and put into the manual), or, if for some unknown reason this useful
functionality is now declared by the PHP staff to be evil, the reasons
should be revealed and the appropriate details put into the manual so that
we know it know longer works in PHP5, and why.
I figure it's just a bug ;)
Reproduce code:
---------------
class test {
function f1() {
unset($this);
}
function f2() {
$this = NULL;
}
}
$obj = new test;
var_dump($obj);
$obj->f1();
var_dump($obj);
$obj->f2();
var_dump($obj);
unset($obj);
var_dump($obj);
Expected result:
----------------
object(test)(0) {
}
NULL
NULL
NULL
Note: if f1() worked, there would be no need to run f2(), because $obj
would have been unset. But, both methods should result in $obj being
NULL.
OR:
object(test)(0) {
}
object(test)(0) {
}
NULL
NULL
This would also be an acceptable result, because there is an alternate
method (f2()) that can be used. This is the result from the latest version
of PHP4.
Actual result:
--------------
>From PHP5:
Fatal error: Cannot re-assign $this in /home/test2.php on line 6
So, f2(), which sets $this to NULL, doesn't work. Commenting that out
produces:
object(test)#1 (0) {
}
object(test)#1 (0) {
}
NULL
So, neither of the methods f1() or f2() work.
>From the latest version of PHP4:
object(test)(0) {
}
object(test)(0) {
}
NULL
NULL
This is fine, as the desired effect can still be accomplished.
In earlier versions of PHP4, both f1() and f2() work fine.
--
Edit bug report at http://bugs.php.net/?id=36971&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=36971&r=trysnapshot44
Try a CVS snapshot (PHP 5.1):
http://bugs.php.net/fix.php?id=36971&r=trysnapshot51
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=36971&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=36971&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=36971&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=36971&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=36971&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=36971&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=36971&r=support
Expected behavior: http://bugs.php.net/fix.php?id=36971&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=36971&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=36971&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=36971&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=36971&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=36971&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=36971&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=36971&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=36971&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=36971&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=36971&r=mysqlcfg
