Description:
------------
Extending the built-in class 'mysqli' doesn't give the expected and desired result. The extended class doesn't have the members the parent class has and is unusable.

We found a related mailinglist entry from more than a year ago: http://www.zend.com/lists/engine2/200302/msg00244.html

The possibility to extend built-in classes is a major feature in PHP5 - at least for us ;).

The reproduce code below is a minimal testcase - other more complicated tests failed as well.

Reproduce code:
---------------
class DB extends mysqli
{	
}

$DB1 = new DB('localhost', 'root', '', 'probase2');
$DB2 = new mysqli('localhost', 'root', '', 'probase2');

var_dump($DB1->thread_id);
var_dump($DB1->error);
var_dump($DB1->errno);

var_dump($DB2->thread_id);
var_dump($DB2->error);
var_dump($DB2->errno);

Expected result:
----------------
int(97)
string(0) ""
int(0)
int(98)
string(0) ""
int(0)

Actual result:
--------------
<br />
<b>Notice</b>:  Undefined property:  DB::$thread_id in <b>d:\htdocs_php5\ProBase2\TRUNK\probase\libsys\test.php</b> on line <b>10</b><br />
NULL
<br />
<b>Notice</b>:  Undefined property:  DB::$error in <b>d:\htdocs_php5\ProBase2\TRUNK\probase\libsys\test.php</b> on line <b>11</b><br />
NULL
<br />
<b>Notice</b>:  Undefined property:  DB::$errno in <b>d:\htdocs_php5\ProBase2\TRUNK\probase\libsys\test.php</b> on line <b>12</b><br />
NULL
int(97)
string(0) ""
int(0)