Not bug, works just as expected. (Don't do this :)

.

Reclassifying to Feature Request.

Calling global in the global scope should not be done.  It represents poor coding practices, however if someone on the Zend team wants to make this work (the basic problem is that the object is copied rather than referenced) here's the guys official feature request.

The problem is with using global in the global scope.

The manual clearly states that 

global $x1;

is equivalent to 

$x1 =& $GLOBALS['x1'];

If you rewrite you example with that code to:


<?
class X
{
    var $f = 'PHP sucks';
};

$x1 = new X;
$x2 = new X;
$z1 = &$x1;
$z2 = &$x2;

{
    $x1 =& $GLOBALS['x1'];
//    global $x1;
    $x1->f = 'PHP is OK!';
}

{
    $x2->f = 'PHP is OK!';
}

echo "x1.f=".$x1->f."\n";
echo "x2.f=".$x2->f."\n";
echo "z1.f=".$z1->f."\n";
echo "z2.f=".$z2->f."\n";

?>

You can see that the problem is that $x1 gets redefined, 
leaving $z1 a reference to the original $x1.  Thus I'm 
marking this bug bogus.  The manual should probably be 
updated to say that not only is calling global in the 
global scope pointless, it may also not do what you think 
it does.

BTW: your attitude (as demonstrated in 23365) is piss-poor.  
PHP is a volunteer effort, calling someone 'ungrateful' for 
requesting a reproducing testcase is uncalled for.  If you 
want to be a tool, I'd suggest fixing your own problems, or 
switching to a non-volunteer supported where people are 
paid to put up with your immature antics.

p.s. this syntax works in php5.