Question

I cannot understand this behavior: My isset() check is always returning false on a property that has a value for sure!

<?php

  class User {
    protected $userId; // always filled
    protected $userName; // always filled

    /**
     * Magic method for the getters.
     * 
     * @param type $property
     * @return \self|property
     */
    public function __get($property) {
        if (property_exists($this, $property)) {
            return $this->$property;
        } else {
            throw new Exception('property '.$property.' does not exist in '.__CLASS__.' class');
        }
    }

  }

?>

When I check this variable from another class with the following:

isset($loggedUser->userName); // loggedUser is my instantiation of the User.php

It returns FALSE?? But when I overload the __isset() function in my User.php I get TRUE back as I expected:

public function __isset($name)
{
    return isset($this->$name);
}

Just to be clear:

echo $loggedUser->name;   // result "Adis"
isset($loggedUser->name); // results in FALSE, but why?

Thanks for your help!

Answer 1

$userName is protected, which means you can’t access it outside the class, in this example from your $loggedUser init.
You need one of the following:
1) make it public
2) write a custom method
3) make a magic(__isset) function

EDIT: When using isset() on inaccessible object properties, the __isset() overloading method will be called, if declared.isset() php docs

I hope this explains it.