ID: 43484
User updated by: robin_fernandes at uk dot ibm dot com
Reported By: robin_fernandes at uk dot ibm dot com
Status: Bogus
Bug Type: Scripting Engine problem
Operating System: Windows
PHP Version: 5.3CVS-2007-12-03 (snap)
New Comment:
Hi Johannes,
Thanks for looking into this. I understand your comment, but I can't
quite see how it relates to the behaviour described in the bug report.
The bug describes how, using call_user_func_array(), one can force a
function defined with pass-by-value args to take those args by reference
- even with call time pass by reference DISABLED in php.ini.
Note that this odd behaviour is now documented (thanks to bug 43079).
But the documentation writer suggested raising a functional bug, because
the behaviour is potentially dangerous.
Here is a simplified example:
<?php
function byValue($a) {
$a = 'This assignment should not affect global scope!';
}
$args = array('original');
$ref = &$args[0]; //dummy reference - remove to change behaviour
call_user_func_array('byValue', $args);
var_dump($args);
?>
---( Expected Output )---
array(1) {
[0]=>
string(8) "original"
}
---( Actual Output )---
array(1) {
[0]=>
&string(47) "This assignment should not affect global scope!"
}
Previous Comments:
------------------------------------------------------------------------
[2008-03-08 22:56:39] [EMAIL PROTECTED]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php
$args = array('original.a', 'original.b');
This puts a copy of the value 'original.a' into that array.
------------------------------------------------------------------------
[2007-12-03 14:09:12] robin_fernandes at uk dot ibm dot com
Description:
------------
This issue was originally raised as documentation bug 43079. Raising as
Scripting Engine problem as suggested by vrana at php dot net.
The pass-by-value/pass-by-ref behaviour of call_user_func_array() is
not intuitive (see the user contributed notes on the documentation page:
http://php.net/call_user_func_array ).
It appears that the way in which an argument is passed depends not on
the target function signature, but rather on whether its entry in
$param_arr is referenced or not.
Specifically, it is possible to force an argument to be passed by
reference to a function which expects a pass-by-value argument, even
with call time pass by reference DISABLED in php.ini.
Reproduced on php5.3 and php6 snaps on Windows.
Reproduce code:
---------------
<?php
function byRef(&$a, &$b) {
$a = 'changed.a';
$b = 'changed.b';
}
function byVal($a, $b) {
$a = 'changed.a';
$b = 'changed.b';
}
//Currently, this forces a pass-by-ref function to take args by val:
$args = array('original.a', 'original.b');
call_user_func_array('byRef', $args);
var_dump($args);
//Currently, this forces a pass-by-val function to take 1 arg by ref.
//This works even with call-time pass-by-ref DISABLED in php.ini.
$args = array('original.a', 'original.b');
$ref = &$args[0];
call_user_func_array('byVal', $args);
var_dump($args);
?>
Expected result:
----------------
array(2) {
[0]=>
string(9) "changed.a"
[1]=>
string(9) "changed.b"
}
array(2) {
[0]=>
&string(10) "original.a"
[1]=>
string(10) "original.b"
}
Actual result:
--------------
array(2) {
[0]=>
string(10) "original.a"
[1]=>
string(10) "original.b"
}
array(2) {
[0]=>
&string(9) "changed.a"
[1]=>
string(10) "original.b"
}
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=43484&edit=1
