uninitialized constant ActionDispatch::Session::En

Question

i'm on rails 4 with passenger. everything was working great until i did a bundle just now. now i'm hitting the following error:

Web application could not be started

uninitialized constant ActionDispatch::Session::EncryptedCookieStore (NameError)
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application/configuration.rb:144:in `const_get'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application/configuration.rb:144:in `session_store'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application.rb:345:in `block in default_middleware_stack'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application.rb:307:in `tap'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application.rb:307:in `default_middleware_stack'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/engine.rb:494:in `app'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application/finisher.rb:34:in `block in <module:Finisher>'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/initializable.rb:30:in `instance_exec'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/initializable.rb:30:in `run'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/initializable.rb:55:in `block in run_initializers'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:150:in `block in tsort_each'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:183:in `block (2 levels) in each_strongly_connected_component'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:219:in `each_strongly_connected_component_from'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:182:in `block in each_strongly_connected_component'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:180:in `each'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:180:in `each_strongly_connected_component'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/tsort.rb:148:in `tsort_each'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/initializable.rb:54:in `run_initializers'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/application.rb:214:in `initialize!'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/rails-2ac97df55230/railties/lib/rails/railtie/configurable.rb:30:in `method_missing'
  /opt/ptolemy-web/config/environment.rb:5:in `<top (required)>'
  config.ru:3:in `require'
  config.ru:3:in `block in <main>'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
  /u/sf/ytl/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
  config.ru:1:in `new'
  config.ru:1:in `<main>'
  /opt/rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/passenger-7ef605967703/helper-scripts/rack-preloader.rb:82:in `eval'
  /opt/rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/passenger-7ef605967703/helper-scripts/rack-preloader.rb:82:in `preload_app'
  /opt/rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/passenger-7ef605967703/helper-scripts/rack-preloader.rb:127:in `<module:App>'
  /opt/rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/passenger-7ef605967703/helper-scripts/rack-preloader.rb:6:in `<module:PhusionPassenger>'
  /opt/rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/bundler/gems/passenger-7ef605967703/helper-scripts/rack-preloader.rb:5:in `<main>'

my gemfile

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', github: 'rails/rails'

# database
gem 'pg'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   github: 'rails/sass-rails'
  gem 'coffee-rails', github: 'rails/coffee-rails'
  gem 'coffeebeans'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  gem 'therubyracer', platforms: :ruby

  gem 'uglifier', '>= 1.0.3'
end

# UI
gem 'jquery-rails'
gem 'less-rails'
gem 'twitter-bootstrap-rails'
gem 'jquery-ui-rails'
gem 'jquery-datatables-rails', github: 'rweng/jquery-datatables-rails'
gem 'backbone-on-rails'
gem 'd3_rails'
gem 'rails-timeago'
gem 'dygraphs-rails'

# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.0.1'

# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# Use unicorn as the app server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano', group: :development

# To use debugger
# gem 'debugger'

# UI middleware
gem 'passenger', github: 'FooBarWidget/passenger'
gem 'rack-webauth'

my google-foo was rather weak on this matter. can anyone help?

Answer 1

The secret cookie store was recently removed in Rails 4. See Changelog.

In order to get your app working again, replace the line config.session_store :encrypted_cookie_store with config.session_store :cookie_store in config/initializers/session_store.rb. The store will be automatically encrypted.

If unsure. Create a new Rails 4 app (rails new app_name --pre) and have a look at the initializers.

For details see the according commit