Description:
------------
is_file failes to see the file has gone
i wanted to have a script run as long as a file existed, on removing the file is_file was supposed to fail and my program should break out of the loop

Reproduce code:
---------------
test.php:

<?
while (is_file('foo')){
 echo "still there\n"; 
 sleep(1);
}
?>


shellcode:
#> touch foo
#> php test.php &
still there
still there
still there
..
#> rm foo
still there
still there
..



Expected result:
----------------
It should have stopped after rm foo