From:             nuttzy at spellingcow dot com
Operating system: CentOS
PHP version:      5.2.6
PHP Bug Type:     Class/Object related
Bug description:  __isset usage changes behavior of empty()

Description:
------------
Per http://bugs.php.net/bug.php?id=40797, the behavior of empty() was
modified to call the __isset magic method.  There is at least one case
where this changes the behavior of empty() to falsely report "not empty"
when in fact the desired result is "empty".

I suppose you would need an __empty() magic method, but that sounds
heinous.  Overloading docs should at least be updated to warn the
developer.

Reproduce code:
---------------
<?
class myclass
{
    private $_raw_data = array() ;

    function __construct( $data)
    {
        $this->_raw_data = $data ;
    }

    function __isset( $field_name)
    {
        return isset($this->_raw_data[$field_name]);
    }    
}

$_POST['foo']='' ;
$myclass = new myclass( $_POST) ;

// correct reports "isset"
echo (isset($myclass->foo)) ? 'isset' : 'not isset') ;

// incorrectly reports "not empty"
echo (empty($myclass->foo)) ? 'empty' : 'not empty' ;

// a way to get around the broken empty() call
echo ($myclass->foo) ? 'not empty' : 'empty' ;

?>

Expected result:
----------------
isset
empty
empty

Actual result:
--------------
isset
not empty
empty

-- 
Edit bug report at http://bugs.php.net/?id=44899&edit=1
-- 
Try a CVS snapshot (PHP 5.2): 
http://bugs.php.net/fix.php?id=44899&r=trysnapshot52
Try a CVS snapshot (PHP 5.3): 
http://bugs.php.net/fix.php?id=44899&r=trysnapshot53
Try a CVS snapshot (PHP 6.0): 
http://bugs.php.net/fix.php?id=44899&r=trysnapshot60
Fixed in CVS:                 http://bugs.php.net/fix.php?id=44899&r=fixedcvs
Fixed in release:             
http://bugs.php.net/fix.php?id=44899&r=alreadyfixed
Need backtrace:               http://bugs.php.net/fix.php?id=44899&r=needtrace
Need Reproduce Script:        http://bugs.php.net/fix.php?id=44899&r=needscript
Try newer version:            http://bugs.php.net/fix.php?id=44899&r=oldversion
Not developer issue:          http://bugs.php.net/fix.php?id=44899&r=support
Expected behavior:            http://bugs.php.net/fix.php?id=44899&r=notwrong
Not enough info:              
http://bugs.php.net/fix.php?id=44899&r=notenoughinfo
Submitted twice:              
http://bugs.php.net/fix.php?id=44899&r=submittedtwice
register_globals:             http://bugs.php.net/fix.php?id=44899&r=globals
PHP 4 support discontinued:   http://bugs.php.net/fix.php?id=44899&r=php4
Daylight Savings:             http://bugs.php.net/fix.php?id=44899&r=dst
IIS Stability:                http://bugs.php.net/fix.php?id=44899&r=isapi
Install GNU Sed:              http://bugs.php.net/fix.php?id=44899&r=gnused
Floating point limitations:   http://bugs.php.net/fix.php?id=44899&r=float
No Zend Extensions:           http://bugs.php.net/fix.php?id=44899&r=nozend
MySQL Configuration Error:    http://bugs.php.net/fix.php?id=44899&r=mysqlcfg

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