error_messages_for_backport.rb

module ActionView
  module Helpers
    module ActiveModelHelper
      def error_messages_for(*params)
        options = params.extract_options!.symbolize_keys

        if object = options.delete(:object)
          objects = Array.wrap(object)
        else
          objects = params.collect {|object_name| instance_variable_get("@#{object_name}") }.compact
        end

        count  = objects.inject(0) {|sum, object| sum + object.errors.count }
        unless count.zero?
          html = {}
          [:id, :class].each do |key|
            if options.include?(key)
              value = options[key]
              html[key] = value unless value.blank?
            else
              html[key] = 'errorExplanation'
            end
          end
          options[:object_name] ||= params.first

          I18n.with_options :locale => options[:locale], :scope => [:activerecord, :errors, :template] do |locale|
            header_message = if options.include?(:header_message)
              options[:header_message]
            else
              object_name = options[:object_name].to_s
              object_name = I18n.t(object_name, :default => object_name.gsub('_', ' '), :scope => [:activerecord, :models], :count => 1)
              locale.t :header, :count => count, :model => object_name
            end
            message = options.include?(:message) ? options[:message] : locale.t(:body)
            error_messages = objects.sum {|object| object.errors.full_messages.map {|msg| content_tag(:li, ERB::Util.html_escape(msg)) } }.join.html_safe

            contents = ''
            contents << content_tag(options[:header_tag] || :h2, header_message) unless header_message.blank?
            contents << content_tag(:p, message) unless message.blank?
            contents << content_tag(:ul, error_messages)

            content_tag(:div, contents.html_safe, html)
          end
        else
          ''
        end
      end
    end
  
    class FormBuilder
      def error_messages(options = {})
        @template.error_messages_for(@object_name, objectify_options(options))
      end
    end
  end
end