Rails 4 and Devise: nested attributes validations not working - ruby-on-rails

Question

I am using Devise in my rails 4 app. I have a member model (for devise) and a user model that contains all the profile info for each member. A member accepts nested attributes for user. See the form below for a new registration as well as the custom routes in my routes.rb file.
My problem is this - everything works fine except validation of the user attributes. If I leave first name and last name blank, then it validates (but crashes like this:
But all the other validations for Member (the devise model) work - they end up on the /members page with the error message displayed as it should. I am unsure as to what is going on - shouldn't devise show the error messages for the invalid nested attributes?
class Members::RegistrationsController < Devise::RegistrationsController
# GET /resource/sign_up
def new
build_resource({})
self.resource.user = User.new
respond_with self.resource
end
# POST /resource
def create
super
resource.user.ip_address = request.remote_ip
resource.user.email = resource.email
resource.user.save!
end
private
def sign_up_params
allow = [:provider, :uid, :email, :password, :password_confirmation, user_attributes: [:member_id, :email, :first_name, :last_name, :institution, :city, :country, :job_title, :about, :tag_list, :picture, :ip_address]]
params.require(resource_name).permit(allow)
end
end
Member.rb
class Member < ActiveRecord::Base
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable, :omniauthable, :trackable
has_one :user, dependent: :destroy, autosave: true
accepts_nested_attributes_for :user
end
User.rb
class User < ActiveRecord::Base
belongs_to :member
validates :first_name, presence: true
validates :last_name, presence: true
end
In my routes.rb
devise_for :members, controllers: {registrations: 'members/registrations',
omniauth_callbacks: 'members/omniauth_callbacks',
sessions: 'members/sessions' }
In my members/registrations/new.html.erb
<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name), html: { role: "form" }) do |f| %>
<%= f.fields_for(:user) do |user_fields| %>
<%= user_fields.text_field :first_name, autofocus: true, class: 'form-control', :placeholder => "First name" %>
<%= user_fields.text_field :last_name, class: 'form-control', :placeholder => "Last name" %>
<% end %>
<%= f.email_field :email, autofocus: true, class: "form-control", :placeholder => "Email" %>
<%= f.password_field :password, class: "form-control", :placeholder => "Password" %>
<%= f.submit t('.sign_up', :default => "Sign up"), class: "btn btn-danger" %>
<% end %>
Here is the log for this
Started POST "/members" for ::1 at 2015-07-16 15:18:54 +0100
Processing by Members::RegistrationsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"sIxK1PTvrxNHUBdDXAtKFLLG27FvqypQ3mUvo398tHOMomi1S3I2o3vBM GwrF6PVN1NFBR5vnr8ezKP6XnMzqw==", "member"=>{"user_attributes"=>{"first_name"=>"", "last_name"=>""}, "email"=>"slfwalsh#gmail.com", "password"=>"[FILTERED]"}, "commit"=>"Sign up"}
(0.2ms) begin transaction
Member Exists (0.3ms) SELECT 1 AS one FROM "members" WHERE "members"."email" = 'slfwalsh#gmail.com' LIMIT 1
(0.1ms) rollback transaction
Rendered devise/shared/_links.erb (9.9ms)
Rendered members/registrations/new.html.erb within layouts/static_home_page (19.8ms)
Rendered layouts/_static_login_header.html.erb (4.1ms)
(0.1ms) begin transaction
(0.1ms) rollback transaction
Completed 422 Unprocessable Entity in 1499ms

Answer 1

The reason why you are seeing that page is because save! triggers validation errors if the validation for any of the attributes is failed and those errors are displayed in the page. On the other hand save doesn't display the validation errors but just cancels the transaction from being saved if any of the validations are failed. Changing your create method like below should solve your problem.
def create
super
resource.user.ip_address = request.remote_ip
resource.user.email = resource.email
resource.user.save
end