ruby on rails - Spree frontend helpers not available, leading to"undefined local variable or method `body_class'" -

i'm trying install spree on existing application. installs successfully, when navigating spree page, "undefined local variable or method 'body_class'" error in spree_frontend-3.0.4/app/views/spree/layouts/spree_application.html.erb, line 10.

body_class method in spree_frontend-3.0.4/app/helpers/spree/frontend_helper.rb, seems helper methods file aren't available. why not?

i tried setting brand new rails app , installing spree on that, , worked. there's odd existing app that's interfering spree, can't think of might be.

here's gemfile, in case helps:

    source 'https://rubygems.org'      ruby '2.2.0'     gem 'rails', '4.2.3'     gem 'sass-rails', "~> 4.0.2"     gem 'celluloid', '~> 0.16.0'     gem 'unicorn'     gem 'bootstrap-sass', '~> 3.3.5'     gem 'bcrypt-ruby', '3.1.2'     #gem 'faker', '1.1.2'     gem 'kaminari'     gem 'kaminari-bootstrap', '~> 3.0.1'     gem 'pg'     gem 'devise', '>= 3.5.1'     gem "devise-async"     gem 'dependent-fields-rails'     gem 'underscore-rails'     gem "marco-polo"     gem 'aws-sdk', '~> 1.63'     gem 'aws-sdk-resources', '~> 2'     gem 'paperclip', "~> 4.1"     gem 'delayed_job_active_record'     gem 'delayed_job_web'     # gem 'hirefire', :github => 'michaelkeenan/hirefire'     gem 's3_direct_upload', :github => 'maxgillett/s3_direct_upload'     # gem 's3_multipart', :github => 'maxgillett/s3_multipart'     #gem "s3_multipart", :path => "../s3_multipart"     gem "s3_multipart", :github => 'michaelkeenan/s3_multipart', :tag => 'v0.0.11.9'     #gem 'rest_in_place', :git => "git://github.com/michaelkeenan/rest_in_place.git"     gem 'best_in_place', '~> 3.0.1'     gem 'pundit'     gem 'data-confirm-modal', github: 'ifad/data-confirm-modal'     gem 'money-rails'     gem 'font-awesome-sass'     # gem 'jquery-turbolinks'     gem 'rubyzip', '~> 1.1.6', require: 'zip'     gem 'obfuscate_id', '~> 0.0.5', :git => "git://github.com/michaelkeenan/obfuscate_id.git"     gem 'redcarpet'     gem 'pagedown-bootstrap-rails'     gem 'honeybadger'     gem "paranoia"     gem 'paranoia_uniqueness_validator', '1.1.0'     gem 'unscoped_associations'     gem 'friendly_id', '~> 5.1.0'     gem 'nokogiri'     gem "hirefire-resource"     gem 'acts_as_list'     gem 'mailboxer', '~> 0.13.0'     gem 'zeroclipboard-rails'     gem 'bootstrap-datepicker-rails'     gem "awesome_print", require:"ap"     gem 'cloudfront-signer'     gem 'rack-attack'      group :development         gem 'better_errors'         gem 'binding_of_caller', :platforms=>[:mri_19, :mri_20, :rbx]         gem 'rails_layout'         gem 'bullet'         gem 'did_you_mean', '~> 0.9.5'         gem 'quiet_assets'         gem 'meta_request'         gem 'pry-rails'     end      group :development, :test         gem 'spring', '~> 1.3.6'         gem "spring-commands-rspec"         gem 'minitest'         gem 'rspec-rails', '~> 3.2'         gem 'guard-rspec'         gem 'rb-fsevent', :require => false         #gem 'guard-zeus'         gem 'growl', '1.0.3'         gem 'childprocess', '0.5.0'         gem 'email_spec'         gem 'pry-byebug'         gem 'pry-stack_explorer'         gem 'pry-remote'     end      group :test         gem 'selenium-webdriver', '2.41.0'         gem 'capybara'         gem 'capybara-webkit'         gem 'factory_girl_rails', '4.2.1', :require => false         gem 'database_cleaner'     end      #group :assets         gem 'sprockets-rails', :require => 'sprockets/railtie'         gem 'coffee-rails', '~> 4.0.0'         gem 'uglifier', '>= 1.3.0'         gem "fog", "~>1.28"         gem 'asset_sync'     #end      gem 'jquery-rails', '4.0.4'     gem 'jquery-ui-rails', '5.0.5'     gem 'remotipart', '~> 1.2'     # gem 'turbolinks'     gem 'jbuilder', '~> 1.2'      group :doc         gem 'sdoc', '0.3.20', require: false     end      group :production         gem 'rails_12factor', '0.0.2'         gem 'lograge'     end     gem 'spree', '3.0.4' 

this turned out due s3_multipart gem, or rather, due file generated. creates class subclassed applicationcontroller:

class itemuploader < applicationcontroller     ... end 

this breaks helper methods because of conditional in action_controller/railties/helpers.rb:

if klass.superclass == actioncontroller::base && actioncontroller::base.     klass.helper :all end 

someone else reported here.

to solve it, change itemuploader subclass actioncontroller::base. s3_multipart still works change, , doesn't break helper methods.

class itemuploader < actioncontroller::base     ... end