PHP empty($string) return true but string is not empty

Question

<?php
$m->type = 'EVENT';
if (empty($m->type)) {
 var_dump($m->type);
}
?>

This piece of code prints

string(5) "EVENT"

How is this possible?

edit

The $m object is a plain one, with magic __set and __get that store values into a protected array.

<?php
$m->type = 'EVENT';
if ($m->type == NULL) {
 var_dump($m->type);
}
?>

The above mentioned code works as expected (it skips the if body).

• andrewsi: Doesn't do that for me, I'm afraid (PHP 5.3.24)
• Tom: Have you tried storing that string into a variable and then testing it? Like this: $string = $m->type; if(empty($string)){ //code here }
• David Jashi: Try $someVar=$m->type; if (empty($someVar)) { var_dump($m->type); } and tell us, what you get
• cHao: What is $m? (ie: what class?) This doesn't happen with a stdClass, so the type of $m is probably a pretty big factor.
• fullybaked: Is this the only piece of the code or have you just posted a subset? If there is more, a larger context may help

Answer 1

If you're using magic getter within your class, the docs page documents a rather tricky behaviour:

<?php
class Registry
{
 protected $_items = array();
 public function __set($key, $value)
 {
 $this->_items[$key] = $value;
 }
 public function __get($key)
 {
 if (isset($this->_items[$key])) {
 return $this->_items[$key];
 } else {
 return null;
 }
 }
}
$registry = new Registry();
$registry->empty = '';
$registry->notEmpty = 'not empty';
var_dump(empty($registry->notExisting)); // true, so far so good
var_dump(empty($registry->empty)); // true, so far so good
var_dump(empty($registry->notEmpty)); // true, .. say what?
$tmp = $registry->notEmpty;
var_dump(empty($tmp)); // false as expected
?>

• brazorf: I think this may be what's affecting my code. I'll check it out.
• Roman: so use empty($m = $m->type) instead of empty($m->type), and it will work correctly
• usoban: @Roman please don't, inline assignments are classical code smell.