Due to eZ Publish's history, most of the classes use PHP4 style constructors in the form

class MyClass
{
    function MyClass()
    {
        // Constructor
        $this->MyParentClass();
        // More code
    }
}

instead of

class MyClass
{
    public function __construct()
    {
        // Constructor
        parent::__construct();
        // More code
    }
}

This is problematic due to the following reasons:

• If you want to use the parent's constructor, you have to call it explicitely
• Derived classes call the parent constructor by its name instead of parent::__construct() which makes the refactoring of class names cumbersome
• We don't know if and when a future version of PHP will stop supporting the PHP4 constructor methods
• PHP 7 logs deprecation errors unless they are turned off