I would be very surprised to be able to access private properties of Base in the context of Child.
What you see is expected.

but it works expect if the method change to this

function getFields($obj){
  return array('p1'=>$obj->p1);
}

and it work expect in java using reflection

think about: Liskov Substitution Principle

i thing this is the implemention bug of get_object_vars

>but it works expect if the method change to this
>function getFields($obj){ return array('p1'=>$obj->p1); }

Surely Base class can access it's own private properties.
The method belongs to the Base and is executed in it's scope.

code 1: use get_object_vars
1>I would be very surprised to be able to access private properties of
1>Base in the context of Child.

code 2: direct access
2>Surely Base class can access it's own private properties.
2>The method belongs to the Base and is executed in it's scope.

$child=new Child();
$child->getFields(new Base());
what is the context of the method? base or child?

the result direct access and get_object_vars must be the same.

it is a bug that the get_object_vars function do not check the method belongs to, but just check the object class call the method.

I have to agree that something seems bugged here.

Consider the following example:
---------------------------------------------------------------------------------------
<?php

class Base {
	private $baseA   = 'BaseA';
	
	function __construct() {
		echo __METHOD__.' : '. print_r(get_object_vars($this), true)."\n";
		echo 'Direct base : '.$this->baseA."\n";
		echo 'Direct child : '.$this->childA."\n";
	}
}

class Child extends Base{
	private $childA	= 'ChildA';

	function __construct() {
		parent::__construct();
		echo __METHOD__.' : '.print_r(get_object_vars($this), true)."\n";
       }
}

$child = new Child();

?>
---------------------------------------------------------------------------------------
Expected Result:

Base::__construct : Array
(
    [baseA] => BaseA
)

Direct base : BaseA
<br />
<b>Fatal error</b>:  Cannot access private property Child::$childA in <b>PHPDocument7</b> on line <b>9</b><br />
---------------------------------------------------------------------------------------
Actual Result:

Base::__construct : Array
(
    [childA] => ChildA
)

Direct base : BaseA
<br />
<b>Fatal error</b>:  Cannot access private property Child::$childA in <b>PHPDocument7</b> on line <b>9</b><br />
=======================================================================================

It dies properly on $childA reference in the parent class, but interestingly get_object_vars() has no issue with retrieving them.
In other words get_object_vars() does not seem to respect the scope in which it was called.

Following test http://lxr.php.net/source/ZendEngine2/tests/bug27798.phpt
misses the situation because it overrides the private property.

Dmitry, check this out please.

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.