Rails validation error messages: Displaying only one error message per field

Question

Rails displays all validation error messages associated with a given field. If I have three validates_XXXXX_of :email, and I leave the field blank, I get three

Answer 1

Add a method to ActiveModel::Errors class

module ActiveModel
  class Errors
    def full_unique_messages
      unique_messages = messages.map { |attribute, list_of_messages| [attribute, list_of_messages.first] }
      unique_messages.map { |attribute_message_pair| full_message *attribute_message_pair }
    end
  end
end

Add it to a file, like lib/core_ext/rails/active_model/errors.rb. Create a file config/initializers/core_ext.rb and add a require "core_ext/rails/active_model/errors.rb" to it.