Symfony 2 FOSUserBundle: Override form without defining service - php

Question

I' m trying to set up FOSUserBundle for my new application, so I want to override the default FOSUser form. As stated in the FOSUser documentation, I have to define my new form as a service before set up the app/config.yml appropriately. My question is why can't I just set up config.yml like this:
fos_user:
db_driver: orm
firewall_name: admin_area
user_class: abc\abcBundle\Entity\User
registration:
form:
type: abc\abcBundle\Form\Type\UserType
In my last application, I used FOSUserBundle along with PUGXMUltiUserBundle and then my (perfectly working) configuration for PUGXM was:
users:
agents:
entity:
class: abc\NikBundle\Entity\agents
registration:
form:
type: abc\NikBundle\Form\Type\UserType
name: agent_user_registration_form
template: abcNikBundle:ManageUsers:newUser.html.twig
so I supposed this can also be done with FOSUserBundle. Is it impossible and if yes why?

Answer 1

FOSUserBundle allows you to override it's controllers as described in the doc below
https://github.com/FriendsOfSymfony/FOSUserBundle/blob/master/Resources/doc/overriding_controllers.md
This doc actually shows you how to override registration controller and from there it's simply injecting your custom form for validation as in any normal controller.
You can also override the templates by finding the original FOSUserBundle templates under "{ROOT_DIR}/vendor/friendsofsymfony/user-bundle/Resources/views" and copying them into "{ROOT_DIR}/app/Resources/FOSUserBundle/views".
https://github.com/FriendsOfSymfony/FOSUserBundle/blob/master/Resources/doc/overriding_templates.md
It should look like this
Resources
└── FOSUserBundle
└── views
├── ChangePassword
│ ├── changePassword.html.twig
│ └── changePassword_content.html.twig
├── Registration
│ ├── confirmed.html.twig
│ ├── register.html.twig
│ └── register_fail.html.twig
├── Resetting
│ ├── checkEmail.html.twig
│ ├── email.txt.twig
│ ├── passwordAlreadyRequested.html.twig
│ ├── request.html.twig
│ ├── request_content.html.twig
│ ├── reset.html.twig
│ └── reset_content.html.twig
├── Security
│ └── login.html.twig
└── layout.html.twig