ID: 50394
Updated by: stas@php.net
Reported By: tstarling at wikimedia dot org
Status: Open
Bug Type: Feature/Change Request
Operating System: Linux
PHP Version: 5.3.1
New Comment:
This bug is actually deeper than it appears. The problem seems to be
that when __call is used, user function is "simulated" by internal
function processing __call. And there is when it gets hairy, since the
simulating function does not accept parameters by-ref, so they get
separated.
I'll think about how to fix this situation - there might be a way to
carry the reference through...
Previous Comments:
------------------------------------------------------------------------
[2009-12-08 04:46:10] tstarling at wikimedia dot org
For the record, I've isolated this further, and the annotation suggests
it was introduced in r287466 by stas in the course of fixing another
bug.
------------------------------------------------------------------------
[2009-12-07 18:48:45] jani@php.net
Feel free.
------------------------------------------------------------------------
[2009-12-07 09:51:29] tstarling at wikimedia dot org
I fail to see the relationship with bug #49946. That's just someone
reporting behaviour as a bug which was clearly documented in the 5.3
release notes as a deliberate change. I'm not complaining about the
warning, which I just added to demonstrate the problem. I'm not
complaining about the new behaviour of zend_call_function() as of PHP
5.3.0, I'm complaining about the lost reference in __call in PHP 5.3.1.
The fact that the reference is lost makes it impossible for __call to
implement an "out" parameter.
Your own code still demostrates the bug nicely, if you change the $arg
in the foreach to &$arg and then make foo() attempt to modify its
parameter:
<?php
function foo( &$x ) {
$x = 2;
}
class Proxy {
function __call( $name, $args ) {
debug_zval_dump( $args );
$pass = array();
foreach ($args as &$arg)
$pass[] =& $arg;
call_user_func_array( 'foo', $pass );
}
}
$arg = 1;
$args = array( &$arg );
$proxy = new Proxy;
call_user_func_array( array( $proxy, 'bar' ), $args );
debug_zval_dump( $arg );
?>
The final debug_zval_dump() produces 2 in PHP 5.3.0 and 1 in PHP 5.3.1.
Jani, I seem to remember that last time our paths crossed, the issue
ended up on php-dev:
http://marc.info/?l=php-internals&m=124226646727485&w=2
I'm happy to take this one there as well if necessary.
------------------------------------------------------------------------
[2009-12-07 08:00:05] jani@php.net
See bug #49946 and Johannes' comment. This works (in both 5.3 and
5.2):
<?php
function foo( &$x ) {}
class Proxy {
function __call( $name, $args ) {
debug_zval_dump( $args );
$pass = array();
foreach ($args as $arg)
$pass[] =& $arg;
call_user_func_array( 'foo', $pass );
}
}
$arg = 1;
$args = array( &$arg );
$proxy = new Proxy;
call_user_func_array( array( $proxy, 'bar' ), $args );
?>
This really should be documented on the manual at
http://php.net/call_user_func_array
------------------------------------------------------------------------
[2009-12-07 01:40:18] tstarling at wikimedia dot org
Description:
------------
This is a regression in the PHP 5.3.1 release. When you call a __call()
function with a reference parameter, it is silently converted to a
value, by the time it reaches the second argument to __call().
This breaks MediaWiki and has no obvious workaround.
Reproduce code:
---------------
function foo( &$x ) {}
class Proxy {
function __call( $name, $args ) {
debug_zval_dump( $args );
call_user_func_array( 'foo', $args );
}
}
$arg = 1;
$args = array( &$arg );
$proxy = new Proxy;
call_user_func_array( array( &$proxy, 'bar' ), $args );
Expected result:
----------------
PHP 5.3.0 produces:
array(1) refcount(4){
[0]=>
&long(1) refcount(5)
}
Actual result:
--------------
array(1) refcount(4){
[0]=>
long(1) refcount(3)
}
Warning: Parameter 1 to foo() expected to be a reference, value given
in /home/tstarling/src/php/stuff/test-reference-call.php on line 8
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=50394&edit=1