I have to create an alteration of the signup form of the survey installation:

1. create two fields: tax code, province. The province field is a select.
2. When submitting, make a check if the tax code combo => province already exists. If it exists, give an error.

Do you know a clean way to alter the core and achieve this result?

boesbo wrote: I have to create an alteration of the signup form of the survey installation

What is the signup form of the survey installation?

When before voting a poll asks you to register

I have to modify this form:
application / views / register / registerForm.php

And change this controller for validation:
application / controllers / RegisterController.php

I wonder how you manage updates of LimeSurvey? Via GIT?

This is not the problem. I wonder if the API framework framework to exert it.

I have to change: RegisterController.php ok? Is it possible to overwrite a controller? maybe with an Event in a plugin? Is there another recommended method that is not changing the core?

Have you solved your problem in any way? I have to make a similar modification ... and I do not know how to do it without losing it when updating

Code sample : gitlab.com/SondagesPro/extraRegisterPassword