Edit report at https://bugs.php.net/bug.php?id=40880&edit=1
ID: 40880
Comment by: herman dot wetherington at gmail dot com
Reported by: prometheus__0 at hotmail dot com
Summary: public->protected inheritance causes fatal
Status: Bogus
Type: Bug
Package: Class/Object related
Operating System: SUSE SLES 10
PHP Version: 5CVS-2007-03-21 (snap)
Block user comment: N
Private report: N
New Comment:
Apparently, we don't call this a "bug" because this is not caused by a programming
error. So I'm calling it a "massive design flaw" instead.
Previous Comments:
------------------------------------------------------------------------
[2010-10-15 23:33:35] robertoblanko at gmail dot com
Same problem here. You cannot actually apply the singleton pattern to subclasses with this behavior.
I do not see any reason for not calling this a bug.
------------------------------------------------------------------------
[2010-09-07 12:58:35] nickyla83 at yahoo dot fr
I'm in the same situation as our friend "prometheus" here, I am trying to use a
singleton pattern and logically, this should involve being able to encapsulate the subcalasses
information particularly setting up a private constructor for the singleton subclass, IT DEFINITELY
DOES MAKE SENSE, so please try to take this under consideration for the next php engine release.
------------------------------------------------------------------------
[2007-03-21 10:05:25] prometheus__0 at hotmail dot com
is this the 'php'-dev definition?
i'm asking cause wraping a singleton pattern around a subclass makes sense
and the same example is valid for java and c++
to ask it differently: why is it working this way in php? (i'm interested in the background of
this)
my point is that 2 languages allow it and there is an example which is valid, not?
------------------------------------------------------------------------
[2007-03-21 09:43:47] derick@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
This is how it works... you can always open up an API through a new extended interface, but not hide
more.
------------------------------------------------------------------------
[2007-03-21 09:38:19] prometheus__0 at hotmail dot com
Description:
------------
(1) It is not possible to make inherited functions more private, which seems like a bug to me but
(2) it is possible to make inherited functions more public, which shouldn't be possible, afaik.
The example code causes the fatal (1)
if you change
protected function __construct()
to
public function __construct()
from class b
and
public function __construct(){
to
protected function __construct(){
from class a
it works (2)
since i'm not an expert in oop i tried the same example in java and it works the complete
opposite way (the b functions can be more private but not more public)
and in C++ it's the same
i know bug report http://bugs.php.net/bug.php?id=34237 but it
considers point (2)
point (1) is still a bug in my opinion
Reproduce code:
---------------
<?php
class a{
public function __construct(){
print("public construct\n");
}
}
class b extends a{
protected function __construct(){
print("protected construct\n");
}
public static function getInstance(){
return new b();
}
}
$b = b::getInstance();
?>
Expected result:
----------------
protected construct
Actual result:
--------------
Fatal error: Access level to b::__construct() must be public (as in class a) in PHPDocument2 on
line 16
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=40880&edit=1