PHP OOP: Missing argument from construct

Question

The following notice and warning occurs after var_dump has excecuted correctly; i.e. var_dump($params) works, but these errors occur thereafter.

I found that using public function __construct($params='') in Models_Index class will cause ommition of these errors from occuring, but I'm not sure why they occur, or why this helps.

Warning: Missing argument 1 for Models_Index::__construct()

Notice: Undefined variable: params in models_index class on line 7

class Router {
  public function __construct(){
    $cont = new Controller('Passing params');
  }
} 
new Router;

class Controller extends Core_Controller {
  public function __construct($params) {  
    $model = $this->model("Models_Index", $params);
  }
}

class Core_Controller {
  protected function model($model, $params) {
    $model = new Models_Index($params);
    return new $model;
  }
}

class Models_Index extends Core_Model {
  public function __construct($params) {
    var_dump($params); // line 7
  }
}

your Controller class has no constructor, so exactly what are you expecting PHP to do with the $params you're trying to pass into it with new Controller($params)? — Marc B
– Marc B, Commented Oct 8, 2014 at 18:40
Is $params a value when it is sent to the Models_Index constructor? — Crackertastic
– Crackertastic, Commented Oct 8, 2014 at 18:41

msfoster · Accepted Answer · 2014-10-08 18:44:59Z

3

The problem is you return new $model:

return new $model;

.. which is equal to

return new Models_Index();

answered Oct 8, 2014 at 18:44

msfoster

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3 Comments

Jack Over a year ago

Not quite, it would be equal to: new Models_Index($params), so i was returning new new Models_Index($params) - which caused the error. You put me on the right track though, so +1.

msfoster Over a year ago

Ok, my mistake, but I figuered it didnt make sense.

bitsoflogic Over a year ago

Actually, @msfoster is correct that it equals new Models_Index(). If it were triggering new Models_Index($params), you would just be seeing the output twice without errors. This is why it warns a parameter is missing.

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