Overwrite config file composer

thinking about it my approach would work if you were using additional packages, that you wanted to keep updated via your repo but you want to overwrite a core Class in Config Directory say Routes.php then actually i think one of the maintainers needs to answer this one.

If you want to write your own class then thats not difficult and i'm doing that . If its one of your classes then its only a case of giving it a namespace then making sure it can be found . If your class is within a Directory , that itself is inside  app directory then for example i have a class called CheckSpam in a Directory called Andy : 
<?php namespace App\Andy;
 

class CheckSpam
{


from a controller i can make use of my class via stating this in controller:

use \App\Andy\CheckSpam;


then from a method i instantiate class and use a method:


$spamHandle = new CheckSpam();
    //CheckSpam is in app/Andy and has namespace App\Andy
        $logic = $spamHandle->filterSpam($cleanMessage);


f i do a composer update i'm pretty sure only items listed in composer.json will be updated/changed and my class's should be untouched ?