BC break with php 5.2.6 View as Markdown

Hi Marcus,

thanks for this conclusion. I just asked this because this changed in this
release and should noticed in the readme or upgrade process because most
singleton pattern implementations in some frameworks, for ie. ZF are using
this code:

class My_Controller_Front extends Zend_Controller_Front
{
public static function getInstance()
{
if (null === self::$_instance) {
self::$_instance = new self();
}

    return self::$_instance;
}

}

The __constructor in Zend_Controller_Front is private.
I asked a, i think, similar question last nov. About private properties.
http://news.php.net/php.internals/33543

Johannes replied to this:

http://news.php.net/php.internals/33544

Johannes: " That's a feature: Extended classes know nothing about private
stuff in
the parent class. Without that the encapsulation won't be complete."

This means this "was maybe a bug, that i allread talked about" but its now
changed so we should raise a notice about this. That will BREAK
Many many apps out there.

For example, PHPUNIT, ZendFramework, ezComponents.

-- Marco

-----Original Message-----
From: Marcus Boerger [mailto:helly@php.net]
Sent: Thursday, March 27, 2008 10:51 AM
To: Marco Kaiser
Cc: PHP Developers Mailing List; php-qa@lists.php.net
Subject: Re: [PHP-QA] BC break with php 5.2.6

Hello Marco,

Thursday, March 27, 2008, 9:25:48 AM, you wrote:

Hi,

i noticed that some changes was made that 100% break all apps that do
such
stuff:

class x extends y
{
public static function foo()
{
new self();
}
}

class y
{
private function __construct()
{
echo 'y::__construct()' . PHP_EOL;
}
}

x::foo();

with php 5.2.5 i works so that i get an output "y::__construct()" but
with
5.2.6RC and -DEV
it throws an fatal error:

Fatal error: Call to private y::__construct() from context 'x'

The behavior is correct. Maybe something with $this is broken in
earlier
versions. I checked the basic issue here calling an inherited private
constructor directly without anything else involved:

[marcus@zaphod PHP_5_0]$ php -r 'class R{private function
__construct(){}} class D extends R{} new D;'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from context '' in
Command line code on line 1
[marcus@zaphod PHP_5_0]$ cd ../PHP_5_1
[marcus@zaphod PHP_5_1]$ php -r 'class R{private function
__construct(){}} class D extends R{} new D;'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from context '' in
Command line code on line 1
[marcus@zaphod PHP_5_1]$ cd ../PHP_5_2
[marcus@zaphod PHP_5_2]$ php -r 'class R{private function
__construct(){}} class D extends R{} new D;'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from invalid context in
Command line code on line 1
[marcus@zaphod PHP_5_2]$ cd ../PHP_5_3
[marcus@zaphod PHP_5_3]$ php -r 'class R{private function
__construct(){}} class D extends R{} new D;'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from invalid context in
Command line code on line 1
[marcus@zaphod php-cvs]$ cd ../php-cvs
[marcus@zaphod php-cvs]$ php -r 'class R{private function
__construct(){}} class D extends R{} new D;'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from invalid context in
Command line code on line 1

Apparently all of 5.0, 5.1, 5.2, 5.3 and HEAD behave in the same way
and issue a
Fatal error as expected.

Now your code uses self winthin class X which is derived from Y which
has a
private constructor. Let's see whether the ctor is illegally called in
this
example:

[marcus@zaphod PHP_5_0]$ cd ../PHP_5_0
[marcus@zaphod PHP_5_0]$ php -r 'class R{private function
__construct(){echo "R\n";}} class D extends R{static function
f(){var_dump(new self);}} D::f();'
make: sapi/cli/php' is up to date. R object(D)#1 (0) { } [marcus@zaphod PHP_5_0]$ cd ../PHP_5_1 [marcus@zaphod PHP_5_1]$ php -r 'class R{private function __construct(){echo "R\n";}} class D extends R{static function f(){var_dump(new self);}} D::f();' make:sapi/cli/php' is up to date.
R
object(D)#1 (0) {
}
[marcus@zaphod PHP_5_1]$ cd ../PHP_5_2
[marcus@zaphod PHP_5_2]$ php -r 'class R{private function
__construct(){echo "R\n";}} class D extends R{static function
f(){var_dump(new self);}} D::f();'
make: `sapi/cli/php' is up to date.

Fatal error: Call to private R::__construct() from context 'D' in
Command line code on line 1

So yes, there is a bug with the inheritance rules in older versions.

i can remember that i asked a related question last year and someone
told me
it is ok so and its a know behavior.
This change will ie. break ZF too. Any suggestions to this behavior?

Fix the code by finding the correct way that works with both old and
new
versions.

Best regards,
Marcus