#25975 [Opn->Fbk]: PHP 5 object references don't survive serialization
ID: 25975
Updated by: [EMAIL PROTECTED]
Reported By: reiersol at online dot no
-Status: Open
+Status: Feedback
Bug Type: Zend Engine 2 problem
Operating System: Linux RedHat 9.0
PHP Version: 5CVS-2003-10-24 (dev)
New Comment:
Please try using this CVS snapshot:
http://snaps.php.net/php5-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5-win32-latest.zip
Previous Comments:
[2003-12-04 09:52:38] reiersol at online dot no
OK. Here is an example using sessions. Exactly the same thing happens.
v1 = new Bar;
$this->v2 = $this->v1;
}
}
session_start();
if (isset($_SESSION['g'])) {
//Try these two one at a time to see the different behaviors:
//$_SESSION['g']->v2 = "I'm no longer an object";
$_SESSION['g']->v2->value = 42;
} else {
$_SESSION['g'] = new Foo;
}
?>
[2003-11-28 20:40:06] [EMAIL PROTECTED]
Please provide an example script that actually uses sessions,
(it's not the same thing when you do the serialize/unserialize inside
the same script..)
[2003-11-10 05:48:59] reiersol at online dot no
Thanks, but I'm afraid this is not quite good enough.
What I'm getting now after serialize/unserialize is:
object(foo)#3 (2) {
["v1"]=>
&object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
["v2"]=>
&object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
The ampersands occur only after serialization. They indicate that this
is what is known as a reference in PHP 4, which is a symbol table
alias. The objects still don't behave the same before and after. Try
this:
$f->v2 = 'I\'m no longer an object';
$g->v2 = 'I\'m no longer an object';
var_dump($f);
var_dump($g);
As before, $f is the object before serialize/unserialize, $g is the
object after. The output is:
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
string(23) "I'm no longer an object"
}
object(foo)#3 (2) {
["v1"]=>
&string(23) "I'm no longer an object"
["v2"]=>
&string(23) "I'm no longer an object"
}
As I understand it, in $f we are replacing an object reference with a
string. In $g, we are replacing the value of a variable that's aliased
to another.
You might ask whether this has any practical consequences. I think that
sooner or later it will (in fact, it seems to be happening in my
full-scale example). When it does, it will be very confusing to the
people who encounter the problem. You may get away with this for a
while, but the longer you get away with it the more difficult it might
be to figure out.
[2003-11-09 12:34:43] [EMAIL PROTECTED]
Please try using this CVS snapshot:
http://snaps.php.net/php5-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5-win32-latest.zip
This should be fixed in CVS now.
[2003-11-04 01:23:53] reiersol at online dot no
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
["v2"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/25975
--
Edit this bug report at http://bugs.php.net/?id=25975&edit=1
#25975 [Opn->Fbk]: PHP 5 object references don't survive serialization
ID: 25975
Updated by: [EMAIL PROTECTED]
Reported By: reiersol at online dot no
-Status: Open
+Status: Feedback
Bug Type: Zend Engine 2 problem
Operating System: Linux RedHat 9.0
PHP Version: 5CVS-2003-10-24 (dev)
New Comment:
Please provide an example script that actually uses sessions,
(it's not the same thing when you do the serialize/unserialize inside
the same script..)
Previous Comments:
[2003-11-10 05:48:59] reiersol at online dot no
Thanks, but I'm afraid this is not quite good enough.
What I'm getting now after serialize/unserialize is:
object(foo)#3 (2) {
["v1"]=>
&object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
["v2"]=>
&object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
The ampersands occur only after serialization. They indicate that this
is what is known as a reference in PHP 4, which is a symbol table
alias. The objects still don't behave the same before and after. Try
this:
$f->v2 = 'I\'m no longer an object';
$g->v2 = 'I\'m no longer an object';
var_dump($f);
var_dump($g);
As before, $f is the object before serialize/unserialize, $g is the
object after. The output is:
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
string(23) "I'm no longer an object"
}
object(foo)#3 (2) {
["v1"]=>
&string(23) "I'm no longer an object"
["v2"]=>
&string(23) "I'm no longer an object"
}
As I understand it, in $f we are replacing an object reference with a
string. In $g, we are replacing the value of a variable that's aliased
to another.
You might ask whether this has any practical consequences. I think that
sooner or later it will (in fact, it seems to be happening in my
full-scale example). When it does, it will be very confusing to the
people who encounter the problem. You may get away with this for a
while, but the longer you get away with it the more difficult it might
be to figure out.
[2003-11-09 12:34:43] [EMAIL PROTECTED]
Please try using this CVS snapshot:
http://snaps.php.net/php5-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5-win32-latest.zip
This should be fixed in CVS now.
[2003-11-04 01:23:53] reiersol at online dot no
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
["v2"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
[2003-11-04 00:28:17] [EMAIL PROTECTED]
Add the missing expected result to your last example.
[2003-10-31 03:42:04] reiersol at online dot no
I guess I'll have to expand my example:
class Bar { var $value = 0; }
class Foo {
var $v1;
var $v2;
function Foo() {
$this->v1 = new Bar;
$this->v2 = $this->v1;
}
}
$f = new Foo;
$f->v2->value = 42;
var_dump($f);
$g = unserialize(serialize($f));
$g->v2->value = 'and now for something completely different';
var_dump($g);
Here's the output:
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#5 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
That should at least make it clear that there's a difference in
behavior before and after serialization. And the behavior before
serialization is the behavior of a normal object-oriented language. (I
ported the example to Java just to make sure I wasn't crazy.)
I'm not trying to split hairs. I tried creating the kind of
sophiticated object-oriented structure that PHP 5 makes so much easier.
It worked wonderfully. But then I discovered that the structure didn't
persist across sessions. So I made this simplified example to
demonstrate the problem.
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/25975
--
Edit this bug report at http://bugs.php.net/?id=25975&edit=1
#25975 [Opn->Fbk]: PHP 5 object references don't survive serialization
ID: 25975
Updated by: [EMAIL PROTECTED]
Reported By: reiersol at online dot no
-Status: Open
+Status: Feedback
Bug Type: Zend Engine 2 problem
Operating System: Linux RedHat 9.0
PHP Version: 5CVS-2003-10-24 (dev)
New Comment:
Please try using this CVS snapshot:
http://snaps.php.net/php5-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5-win32-latest.zip
This should be fixed in CVS now.
Previous Comments:
[2003-11-09 10:46:13] reiersol at online dot no
Opening the bug again
[2003-11-04 01:23:53] reiersol at online dot no
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
["v2"]=>
object(bar)#4 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
[2003-11-04 00:28:17] [EMAIL PROTECTED]
Add the missing expected result to your last example.
[2003-10-31 03:42:04] reiersol at online dot no
I guess I'll have to expand my example:
class Bar { var $value = 0; }
class Foo {
var $v1;
var $v2;
function Foo() {
$this->v1 = new Bar;
$this->v2 = $this->v1;
}
}
$f = new Foo;
$f->v2->value = 42;
var_dump($f);
$g = unserialize(serialize($f));
$g->v2->value = 'and now for something completely different';
var_dump($g);
Here's the output:
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#2 (1) {
["value"]=>
int(42)
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (1) {
["value"]=>
int(42)
}
["v2"]=>
object(bar)#5 (1) {
["value"]=>
string(42) "and now for something completely different"
}
}
That should at least make it clear that there's a difference in
behavior before and after serialization. And the behavior before
serialization is the behavior of a normal object-oriented language. (I
ported the example to Java just to make sure I wasn't crazy.)
I'm not trying to split hairs. I tried creating the kind of
sophiticated object-oriented structure that PHP 5 makes so much easier.
It worked wonderfully. But then I discovered that the structure didn't
persist across sessions. So I made this simplified example to
demonstrate the problem.
[2003-10-24 08:08:59] reiersol at online dot no
Description:
Object references inside PHP5 objects are not preserved through
serialize/unserialize like traditional PHP4 references. This means they
cannot be used in session-based applications.
Reproduce code:
---
class Bar {}
class Foo {
var $v1;
var $v2;
function Foo() {
$this->v1 = new Bar;
$this->v2 = $this->v1;
}
}
$f = new Foo;
var_dump($f);
$g = unserialize(serialize($f));
var_dump($g);
print $s1;
Expected result:
This is what I get if I use $this->v2 = &this->$v1 instead of $this->v2
= $this->v1:
object(foo)#1 (2) {
["v1"]=>
&object(bar)#2 (0) {
}
["v2"]=>
&object(bar)#2 (0) {
}
}
object(foo)#3 (2) {
["v1"]=>
&object(bar)#4 (0) {
}
["v2"]=>
&object(bar)#4 (0) {
}
}
Actual result:
--
object(foo)#1 (2) {
["v1"]=>
object(bar)#2 (0) {
}
["v2"]=>
object(bar)#2 (0) {
}
}
object(foo)#3 (2) {
["v1"]=>
object(bar)#4 (0) {
}
["v2"]=>
object(bar)#5 (0) {
}
}
--
Edit this bug report at http://bugs.php.net/?id=25975&edit=1
