Bug #42937 [Com]: __call() method not invoked when methods are called on parent from child class
| From: | bloodynumen at 163 dot com | Date: | Wed, 05 Mar 2014 04:10:50 +0000 |
| Subject: | Bug #42937 [Com]: __call() method not invoked when methods are called on parent from child class | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-184523@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=42937&edit=1
ID: 42937
Comment by: bloodynumen at 163 dot com
Reported by: jmaxwilson at sixteensmallstones dot org
Summary: __call() method not invoked when methods are called
on parent from child class
Status: Closed
Type: Bug
Package: Scripting Engine problem
Operating System: Windows XP
PHP Version: 5.2.4
Assigned To: dmitry
Block user comment: N
Private report: N
New Comment:
5.2.9 : Changed __call() to be invoked on private/protected method access, similar to properties and
__get(). (Andrei)
Previous Comments:
------------------------------------------------------------------------
[2007-11-12 09:12:31] dmitry@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.
------------------------------------------------------------------------
[2007-11-10 00:35:06] stas@php.net
I think parent:: should use __call, since it's not in fact a static call.
------------------------------------------------------------------------
[2007-10-12 21:46:43] jmaxwilson at sixteensmallstones dot org
Thanks for the feedback. However, adding a magic __callstatic() method doesn't actually fix
the problem. I think there is some misunderstanding about the scope resolution operator (::). While
it is often used to access the static methods of a class, when applied to the keyword
"parent" it is used to access the _instance_ methods of a the parent class. So, calling
parent::getVersion() is calling the _instance_ method of the parent from the child class, not a
static method. Why is this important? What if the method needs to get or set properties of the
instance? It must be an instance method. The $this pseudo-variable is not even available within
static methods.
To illustrate, the example code can be modified like this:
<?php
class A {
var $arrValues = array();
function __construct() {
$this->arrValues['PHP'] = "PHP " . phpversion();
}
function __call($strMethod, $arrArgs) {
return $this->arrValues['PHP'];
}
}
class B extends A {
function getVersion() {
return parent::getVersion() . " Rocks!";
}
}
$A = new A();
echo $A->getVersion() . "<br/>";
$B = new B();
echo $B->getVersion() . "<br/>";
?>
It would be incorrect for the engine to call the __callstatic() magic method when a child class
calls a parent's method. I hope that is not what 5_3 does.
------------------------------------------------------------------------
[2007-10-12 10:11:04] judas dot iscariote at gmail dot com
This is fixed in 5_3 but you have to define __callstatic like this
<?php
class A {
function __call($strMethod, $arrArgs) {
return "PHP " .phpversion();
}
static function __callstatic($strMethod, $arrArgs)
{
return "PHP " .phpversion();
}
}
class B extends A {
function getVersion() {
return parent::getVersion() . " Rocks!";
}
}
$A = new A();
echo $A->getVersion() . "<br/>";
$B = new B();
echo $B->getVersion() . "<br/>";
?>
------------------------------------------------------------------------
[2007-10-11 23:08:54] jmaxwilson at sixteensmallstones dot org
Description:
------------
If __call() is used to implement a method in a parent class, and the method is overridden in an
inherited child class using a real method declaration that calls parent::methodName(), __call() is
never invoked and PHP reports a fatal error saying that the method is undefined.
You can work around the bug by replacing parent::methodName() with
parent::__call('methodName',null), but it means that you have to know which of the
parent's methods are implemented using __call() in order to override them in a child class.
The child class should be agnostic to whether the parent's methods are real or magic.
This bug was reported in PHP5.1 RC1 (http://bugs.php.net/bug.php?id=34739) but was improperly marked
as bogus with the explanation that "__call() is not used when calling static methods."
The use of the paamayim-nekudotayim (::) with the parent keyword is not to resolve static scope but
to resolve inherited scope for an overridden method, therefore the issue should be reconsidered.
Reproduce code:
---------------
<?php
class A {
function __call($strMethod, $arrArgs) {
return "PHP " .phpversion();
}
}
class B extends A {
function getVersion() {
return parent::getVersion() . " Rocks!";
}
}
$A = new A();
echo $A->getVersion() . "<br/>";
$B = new B();
echo $B->getVersion() . "<br/>";
?>
Expected result:
----------------
PHP 5.2.4
PHP 5.2.4 Rocks!
Actual result:
--------------
PHP 5.2.4
Fatal error: Call to undefined method A::getversion() in C:\www\test.php on line 10
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=42937&edit=1