Avoid Overloading of attributes when using magic methods

Question

I have the following PHP class:

<?php
class User{
    private $email = null;
    private $pass = null;

    public function __set($atrib, $value){
        $this->$atrib = $value;
    }

     public function __get($atrib){
        return $this->$atrib;
    }
}
?>

when I was testing I got the following error:INDIRECT MODIFICATION OF OVERLOADED PROPERTY HAS NO EFFECT researched and saw that this error is directly linked to the magic methods so I searched a solution to the problem, I removed the attributes $email and $pass from the class the problem was solved but this lenvanted a question: How I could determine the attributes of the class without generating error: Inderect modification ...?

Example of use:

$user = new User();
$user->email = $_GET['email'];
$user->pass = $_GET['pass'];
loginSearch($conn,$user);
function loginSearch($conn,$user){
        $query = "SELECT email, pass FROM usuarios WHERE email = :email AND pass = :pass";
        $stmt = $conn->prepare($query);
        $stmt->bindParam(':email',$user->email,PDO::PARAM_STR);
        $stmt->bindParam(':pass',$user->pass,PDO::PARAM_STR);
        return $stmt;
    }

Error happens on lines: $stmt->bindParam(':email',$user->email,PDO::PARAM_STR); and $stmt->bindParam(':pass',$user->pass,PDO::PARAM_STR);

Note: Omit connection creation and the execute of stmt.

Screenshot of the error generated:

Answer 1

When I had this problem, the solution was to declare __get with return by reference.

This can be done through the character &.

Behold:

<?php
class User{
    private $email = null;
    private $pass = null;

    public function __set($atrib, $value){
        $this->$atrib = $value;
    }

     public function &__get($atrib){
        return $this->$atrib;
    }
}
?>