Symfony 3.4 How to override service from vendor?

Question

symfony

How to override the first.php class in the main bundle, which is located in the vendor section of the framework? I can't touch the vendor files and I need to override the function that is in this class. I could not get along with the documentation on this issue. I ask for advice

Answer 1

Use decoration: https://symfony.com/doc/current/service_container/...
UPD: Reread the question. You just need to create your own class and inherit from first.php. And change the method in it. And only then register it as a service.