When I validate some data :

$violations = $this->validator->validate($data, new UserConstraintList());

I don't find what is the best solution to detect extra-field violation.
Actually, in my app, extra field is not an error but I want to notice end-user that some extra fields has been sent.

I thought that the code const NO_SUCH_FIELD_ERROR = 2; was a good way to detect it, but a lot of constraints has the same code (2) :/

So, for now, to detect if an extra field error is inside the violation list, I have to check the error message ... it's really dirty but I don't find other solutions.

Any ideas?