php5.0RC3
the same problem.
But I discovered, that the second assignment do things right
e.g.:
class a extends DOMDocument {
    private $prop = array ();
    public function __construct () {parent::__construct ()}
    public function func () {
        $this->prop[] = 'test';
        $this->prop[] = 'test';
    }
}
$o = new a ();
$o->func ();
var_dump ($o);

This is much like the constructor bug in PHP4, because $this in the constructor doesn't properly reference the object being constructed.

One way I normally get round this in PHP4 is to use the Factory pattern, where you do 

class A {

    static public function &Factory() {
        // Use this as a replacement to the constuctor
        $obj = &new A();
        $obj->var = 'Foo Bar';
        return $obj;
    }
}

you just need to construct classes using the static member function like ...

$obj = &A::Factory();

instead of 

$obj = &new A();

e.g.

class z extends domDocument{
	/** variable can have name */
	var $y=Array();
	var $x;
	function __construct(){
		$this->y['doh']='me';
		$x='aaaaahhhh';
		print_r($this->y);	
		echo $x;
	}

	function &Factory() {
		$obj = new z();
		$obj->y['doh2']='me2';
		return $obj;
	}
}
$z= &z::Factory();
print_R($z);

However this to me does seem like a PHP Bug. It's very hard with internal classes to know what behaviours are bugs and "features". A submitted http://bugs.php.net/29092 and apparantly it's not a bug, however there is no mentioning of this in the documentation. As a result the bug is really a documentation bug in my eyes.

Regards
Jason

It's fixed in mysqli now (cvs).

/Georg

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.

The fix in CVS is reverted

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.