ID: 50380
User updated by: dkr at mindwerk dot de
Reported By: dkr at mindwerk dot de
Status: Verified
Bug Type: Scripting Engine problem
Operating System: linux 2.6.21
PHP Version: 5.2.11
New Comment:
Hm, i just think that this is an endless loop that should throw any
error like "max function nesting reached" or something. The following
codes are 2 easier examples that will fault:
Reproduce code #1:
------------------
<?php
class Foo {
static function __call($f,$a) {
static $call = 0;
test();
}
}
function test() {
call_user_func_array(array('Foo','__call'),array(0,array()));
}
test();
?>
Reproduce code #2:
------------------
<?php
function Bar() {
Foo();
}
function Foo() {
Bar();
}
Foo();
?>
Expected result:
----------------
Fatal Error: Maximum calls of nested functions reached in ... on line
...
Actual result:
--------------
Segmentation fault
Previous Comments:
------------------------------------------------------------------------
[2009-12-08 16:59:46] felipe@php.net
__call activated on class: Foo
Warning: String is not zero-terminated
(ZZZZZZ���) (source:
/home/felipe/dev/php5_2/Zend/zend_execute_API.c:414) in
/home/felipe/dev/bug.php on line 15
[Tue Dec 8 14:59:22 2009] Script: '../bug.php'
---------------------------------------
/home/felipe/dev/php5_2/Zend/zend_execute_API.c(414) : Block 0x08b757f0
status:
/home/felipe/dev/php5_2/Zend/zend_variables.c(35) : Actual location
(location was relayed)
Beginning: Cached
Freed (invalid)
Start: OK
End: OK
---------------------------------------
Foo: foobar
[Tue Dec 8 14:59:22 2009] Script: '../bug.php'
/home/felipe/dev/php5_2/Zend/zend_object_handlers.c(767) : Freeing
0x08B75B80 (44 bytes), script=../bug.php
[Tue Dec 8 14:59:22 2009] Script: '../bug.php'
/home/felipe/dev/php5_2/Zend/zend_object_handlers.c(775) : Freeing
0x08B75E7C (6 bytes), script=../bug.php
=== Total 2 memory leaks detected ===
------------------------------------------------------------------------
[2009-12-08 16:33:13] dkr at mindwerk dot de
No, that is NOT BOGUS i think, there is something went wrong, and it
took me quite a while finding the error in the app (using strace etc),
and quite a while yet to reproduce this behavior with a small code
snippet that will SEGFAULT.
Note: Currently only tested on 5.2.11 and 5.2.0-8+etch15
Reproduce code:
---------------
<?php
class Foo
{
function __call($f,$a)
{
echo("__call activated on class: ".__CLASS__.PHP_EOL);
}
function write($text) {
echo( 'Foo: '.$text.PHP_EOL );
}
function debug($text) {
return call_user_func_array(
array(self,'write'),
array($text,1)
);
}
}
class Bar {
function __construct()
{
Foo::debug("foobar");
}
}
class Baz {
function __construct()
{
Foo::debug("foobar");
}
// here he dies...
function __call($f,$a)
{
echo("__call activated on class: ".__CLASS__.PHP_EOL);
}
}
$bar = new Bar();
$baz = new Baz(); // will cause php to die
?>
Expected result:
----------------
1. Calling non-static function Foo::debug() in Bar::__construct()
a) should throw an function not found error while "self::" is used, as
the engine does a lookup in Bar and does not find any function.
b) should not make the usage of Foo::__call() as it does not interact
in the scope of Class Foo finally?
2. Calling Foo::debug() in Baz::__construct() in Baz::__construct()
a) should use __call as it is defined in Baz, and should rely on the
scope of this class and not the non static called class Foo.. Uncomment
Foo::__call to let the whole thing get more weird, as the text
"Baz::foobar" is normally echoed if Baz::__call is only defined there
(only defined!)
b) should never make the usage of Foo::call() as it does not interact
in the scope of Class Foo finally?
Actual result:
--------------
dkr@*:~$ php test.php
__call activated on class: Foo
Segmentation fault
dkr@*:~$
Actual result without Foo::__call():
------------------------------------
dkr@*:~$ php phptest.php
PHP Warning: call_user_func_array(): Unable to call self::write() in *
on line *
Foo: foobar
dkr@*:~$
------------------------------------------------------------------------
[2009-12-04 19:02:39] dkr at mindwerk dot de
If i uncomment Bar::__call, i get the text "foobar" and not "__called!"
or any other error. That is how 5.2.11 (not tried another version)
handles it here currently.. I will try others later.
So, if self:: does rely on the scope of the object we came from
(because we have NOT defined the function as static), Foo::__call should
never be called if self:: or $this is used in Foo, or am i wrong?
It is something like PHP uses Bar::__call if it exists and if not
Foo::__call(), hence we are not extending the class...
Output if Bar::__call commented: "foobar"
Output if Bar::__call uncommented: "__called!"
------------------------------------------------------------------------
[2009-12-04 09:23:35] jani@php.net
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php
If you comment out the __call magic you'll get pretty clear error
message why and what goes wrong.
------------------------------------------------------------------------
[2009-12-04 09:11:12] dkr at mindwerk dot de
Description:
------------
I don't really understand the following situation.. Made some comments
in the code to explain it. There is something wrong with class and
Object scopes: calling a non-static function of another class inside an
object will cause __call (in dependence of existence in the other class)
to different behaviors when using self:: instead of __CLASS__ in the
non-static method.
Reproduce code:
---------------
<?php
class Foo
{
function __call($f,$a)
{
die("__called!\n");
}
function write($text) {
echo($text);
}
// defining debug as static will cause
// the whole thing to work properly
function debug($text) {
return call_user_func_array(
// "self" acts like making a lookup in
// class Bar, fails and then runs the
// magic method in this class, but why?
// i dont have extended the Bar class...
// __CLASS__ will work, but dont work for
// extended classes, as self should do it
array(self,'write'),
array($text,1)
);
}
}
class Bar {
function __construct()
{
Foo::debug("foobar\n");
}
// uncomment the following to make Foo::debug()
// throw the text foobar, ehm? note that we do NOT
// echo any content here... that is something like
// inheritance it should not do? will echo "foobar"..
/*
function __call($f,$a)
{
}
*/
}
$bar = new Bar(); // will cause php to die
Expected result:
----------------
foobar
Actual result:
--------------
__called!
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=50380&edit=1