#28359 [WFx]: serialize() combined with references and objects modifies $this
| From: | mira at st dot jyu dot fi | Date: | Mon, 05 Jul 2004 10:31:00 +0000 |
| Subject: | #28359 [WFx]: serialize() combined with references and objects modifies $this | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-61693@lists.php.net to get a copy of this message | ||
ID: 28359
User updated by: mira at st dot jyu dot fi
Reported By: mira at st dot jyu dot fi
Status: Wont fix
Bug Type: Class/Object related
Operating System: Linux Mandrake 10.0
PHP Version: 4.3.4
New Comment:
I'm totally happy if constructs like
function &setX($x) {
return $this->x = $x; }
are not allowed but then the compiler should complain. The thing is,
4.3.x returns more or less random results if one does this. If the
above is not meant to be equivalent to
function &setX($x) {
$this->x = $x; $a =& $this->x; return $a; }
then the compiler should say so. Surely, returning a reference to a
member isn't disallowed? I've seen PHP to crash in more complex
scenarios because of this.
If PHP 4.x is still supported, this should be fixed (compiler should
report parse error OR returned value should make some sense). The
trigger seems to be modifying a member value and returning a reference
to it in the same statement.
Previous Comments:
------------------------------------------------------------------------
[2004-07-05 11:25:58] moriyoshi@php.net
I mistook this as a PHP5 problem.
This issue has been addressed in PHP5.
You don't return a scalar value that is not a variable
as reference.
OK:
function &foo() {
return $a;
}
NG:
function &bar() {
return $a = %b;
}
function &baz() {
return @$a;
}
------------------------------------------------------------------------
[2004-07-05 11:21:23] moriyoshi@php.net
This bug has been fixed in CVS.
Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
Thank you for the report, and for helping us make PHP better.
------------------------------------------------------------------------
[2004-05-11 14:23:12] mira at st dot jyu dot fi
Description:
------------
See the attached script. The problem is reproduceable with PHP 4.3.4 on
Apache 2.0.48 (Apache and PHP versions that are distributed with
Mandrake 10.0).
The problem seems to be caused by method setX(). If I replace that
method with
function setX($x) {
return $this->x = $x;
}
or
function &setX($x) {
$this->x = $x;
return $this->x;
}
I get the expected end result. [Note that the former doesn't return the
reference so it isn't equivalent to original code.]
Also note that if I remove the first echo, the result of the second
echo is different so it seems that serialize($this) is modifying $this.
It might be that object's internal represenation is already trashed,
though.
Reproduce code:
---------------
<pre><?php
class foo
{
function test() {
$this->setX("28");
echo "this = ".serialize($this)."\n";
echo "this->getX() = ".serialize($this->getX())."\n";
}
function &setX($x) {
return $this->x = $x;
}
function &getX() {
return $this->x;
}
}
$foo =& new foo();
$foo->test();
?></pre>
Expected result:
----------------
this = O:3:"foo":1:{s:1:"x";s:2:"28";}
this->getX() = s:2:"28";
Actual result:
--------------
this = O:3:"foo":1:{s:1:"x";O:3:"foo":1:{s:1:"x";N;}}
this->getX() =
O:3:"foo":1:{s:1:"x";O:3:"foo":1:{s:1:"x";R:2;}}
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=28359&edit=1