using a Hash instead of an an Array for Response#errors

[alperkokmen]

at the moment Response object uses an Array (initialized here) to keep track of errors encountered during validation.

at the moment, it's very human-friendly – i.e. if you wanted to display errors to users, you could just consume errors in your controller after is_valid? check and be done. however, i think it would be better for programmatically traversing errors and making sense of them if errors was a Hash.

easiest pattern i can think of is to leverage the suffix for each validate_XXX method. e.g.

def validate_num_assertion
  # validation fails...
  append_error(:num_assertion, "SAML Response must contain 1 assertion")
end

def validate_destination
  # validation fails...
  append_error(:destination, "The response was received at #{destination} instead of #{settings.assertion_consumer_service_url}")
end

obviously, this would be a breaking change; but, i think errors could be declared as deprecated and a Hash named errors_hash could be defined as a start to allow people upgrade easily. until deprecated error arrays is completely removed, errors and errors_hash could work side-by-side.

repo owners, i would appreciate if you could let me know if this makes sense. if it does, i am open to taking a first stab at it with a pull request.

[pitbulk]

That makes sense but we need to implement a solution that not break current environments.
I'm not enthusiast about the deprecate solution.

[johnnyshields]

@alperkokmen (or anyone else), I think the right way to do this would be to make a global config option that toggles between the old way and the new way. PR would be welcome here.