[PHP-DOC] #40797 [Bgs->Csd]: empty() breaks when overloading with __get

[stephan_schmidt at usa dot com]

 ID:               40797
 User updated by:  stephan_schmidt at usa dot com
 Reported By:      stephan_schmidt at usa dot com
-Status:           Bogus
+Status:           Closed
-Bug Type:         Class/Object related
+Bug Type:         Documentation problem
 Operating System: Windows 200X
 PHP Version:      5.2.1
 Assigned To:      dmitry
 New Comment:

Thanks. The fact that overloading with __isset() also affects empty()
should be documented somewhere, as the page on overloading
(http://us3.php.net/manual/en/language.oop5.overloading.php) contains
only examples for isset().


Previous Comments:
------------------------------------------------------------------------

[2007-03-14 11:24:32] [EMAIL PROTECTED]

To make isset() and empty() work with overloaded properties you must
implement __isset() magic method, otherwise isset() and empty() check
for regular properties.

<?php
class A { 
        public $myArray = array('nonEmptyVar' => 5, 'emptyVar' => '');
        function __get($var) {
                return $this->myArray[$var];
        }
        function __isset($var) {
                return isset($this->myArray[$var]);
        }
}

$a = new A();
echo empty($a->nonEmptyVar) ? 'empty' : 'not empty';
echo '<br>';
echo empty($a->emptyVar) ? 'empty' : 'not empty';
?>




------------------------------------------------------------------------

[2007-03-14 01:36:16] [EMAIL PROTECTED]

Dmitry, please take a look at zend_std_has_property().


------------------------------------------------------------------------

[2007-03-14 00:57:08] stephan_schmidt at usa dot com

The "Actual Results" were from the results of the above script run on a
clean install of PHP 5.2.1 (Win 2000 SP4). No zend extensions are
present or in use.

The code above did not run as expected on any of the Win 200X servers
it was tested on. Line 6 of the output read "int(5) empty" in every
test case.

I suspect it may have to do with the fact that empty() does not accept
a function call as a parameter (i.e. empty(trim($myVar))) since
overloading calls __get. However, one would expect it to also result in
a fatal error if that were the case.

------------------------------------------------------------------------

[2007-03-14 00:11:15] [EMAIL PROTECTED]

That's exactly how it works here.
Make sure you've disable any zend_extensions.

------------------------------------------------------------------------

[2007-03-13 23:57:17] stephan_schmidt at usa dot com

Description:
------------
When overloading with __get() to grab an index of an associative array
inside an object, the overloaded variable returns 'false' when tested
with empty() whether the value is empty or not (see Example 2 for
incorrect results).

Testing overloaded variables that were not in an associative array with
empty() returns the expected results (Example 3).

Reproduce code:
---------------
<?
class A { 
        public $myArray = array('nonEmptyVar' => 5, 'emptyVar' => '');
        function __get($var) {
                return $this->myArray[$var];
        }
}

class B {
        public $nonEmptyVar = 5;
        public $emptyVar = '';
        function __get($var) {
                return $this->$var;
        }
}

$a = new A();
$b = new B();

echo '<p>Example 1:<br>';
echo empty($a->myArray['nonEmptyVar']) ? 'empty' : 'not empty';
echo '<br>';
echo empty($a->myArray['emptyVar']) ? 'empty' : 'not empty';

echo '<p>Example 2:<br>';
var_dump($a->nonEmptyVar);
echo empty($a->nonEmptyVar) ? 'empty' : 'not empty';
echo '<br>';
var_dump($a->emptyVar);
echo empty($a->emptyVar) ? 'empty' : 'not empty';

echo '<p>Example 3:<br>';
echo empty($b->nonEmptyVar) ? 'empty' : 'not empty';
echo '<br>';
echo empty($b->emptyVar) ? 'empty' : 'not empty';
?>

Expected result:
----------------
Example 1:
not empty
empty

Example 2:
int(5) not empty
string(0) "" empty

Example 3:
not empty
empty

Actual result:
--------------
Example 1:
not empty
empty

Example 2:
int(5) empty
string(0) "" empty

Example 3:
not empty
empty


------------------------------------------------------------------------


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