#36172 [Opn]: subclass serialization of parent private members

From: Date: Thu, 26 Jan 2006 18:48:37 +0000
Subject: #36172 [Opn]: subclass serialization of parent private members
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-92521@lists.php.net to get a copy of this message
 ID:               36172
 User updated by:  php at justin dot meagerman dot net
-Summary:          serialize subclasses
 Reported By:      php at justin dot meagerman dot net
 Status:           Open
 Bug Type:         Scripting Engine problem
 Operating System: linux
 PHP Version:      5.1.2
 New Comment:

this is a better title


Previous Comments:
------------------------------------------------------------------------

[2006-01-26 19:42:57] php at justin dot meagerman dot net

Description:
------------
With a private member defined in a parent class and a subclass which
defines a __sleep method, serialization of instances of the subclass
will not save the parent's private member. 

This works as expected if __sleep methods are not defined.

Clearly, because of name conflicts, the child __sleep cannot return the
names of the parent's private members (directly, or indirectly by
calling parent::__sleep), and therefore I think PHP might need to call
__sleep for each class in the hierarchy.

This may be the same issue the no-feedback bug #35779 was trying to
convey.

Reproduce code:
---------------
class A {
  private $a;

  public function __construct() {
    $this->a = 'aVal';
  }

  public function __sleep() {
   return array('a');
  }
}

class B extends A {
  private $b;

  public function __construct() {
    parent::__construct();
    $this->b = 'bVal';
  }

  public function __sleep() {
   //return array('b');   
   return array_merge(parent::__sleep(), array('b'));
  }
}

$serialB = serialize(new B());
print_r(unserialize($serialB));

Expected result:
----------------
B Object
(
    [b:private] => bVal
    [a:private] => aVal
)


Actual result:
--------------
Notice: serialize(): "a" returned as member variable from __sleep() but
does not exist in [...]
B Object
(
    [b:private] => bVal
    [a:private] => 
    [a] => 
)


------------------------------------------------------------------------


-- 
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