How to extend the Controller core class

Showing code you tried and telling the actual error you received is the best way to get a good answer. That said - extending the Controller class is pretty simple - you're just extending a normal PHP class, no special MY_ prefixes needed or anything like that.

1. Make a new BaseController class/file. Make sure it is namespaced so the autoloader can find it.

PHP Code:

<?php namespace App\Controllers;

class BaseController extends \CodeIgniter\Controller 
{
    public function __construct(...$params)
    {
        parent::__construct(...$params);
    }
} 


2. Have all of your new controllers extend BaseController instead of CodeIgniter\Controller.

Note: you don't need to have the constructor shown here unless you need additional tasks in the constructor. I just showed it here to remind people about the parameter packing/un-packing available in PHP 7.

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