没有赋值给变量的PHP类的实例化

Question

I came a cross this line of code in Codeigniter HMVC extension (by Wiredesignz), where a class got instantiated without getting assigned to a variable (class CI in Base.php)

The code :

class CI extends CI_Controller
{
  public static $APP;

  public function __construct() {

    /* assign the application instance */
    self::$APP = $this;

    global $LANG, $CFG;

    /* re-assign language and config for modules */
    if ( ! is_a($LANG, 'MX_Lang')) $LANG = new MX_Lang;
    if ( ! is_a($CFG, 'MX_Config')) $CFG = new MX_Config;

    parent::__construct();
  }
}

/* create the application object */
new CI;

What's the name of this technique? What's the implication?

Answer 1

This has not a name and the implication is, that the constructor is definitely doing too much. The reason one wants to create an instance of a class without referencing it is, that he only wants the constructor wants to be executed, but nothing more. This means, that the constructor "does" something, but a constructor should only ensure, that an object is in a stable/valid state and nothing more.

In short: Don't assume that this is a good practice. The global and self::$APP = $this confirms my opinion that this is a bad piece of code.