Question

Rails app runs fine locally but on the remote server I get this error:

You have already activated rack 1.4.1, but your Gemfile requires rack 1.4.4. Using bundle exec may solve this.

I’ve bundle update-ed several times.

My Gemfile.lock has these lines (... indicates removed lines for clarity):

...
actionpack (3.2.11)
  ...
  rack (~> 1.4.0)
...
rack (1.4.4)
...

Gemfile:

source 'http://rubygems.org'

gem 'rails', '3.2.11'
gem "haml"
gem 'execjs'
gem "rest-client"
gem "stripe"

group :assets do
  gem 'sass-rails', "~> 3.2.4"
  gem 'coffee-rails'
  gem 'uglifier'
  gem 'compass-rails'
  # Deploy with Capistrano
  gem 'capistrano'
  gem 'rvm-capistrano'
end

gem 'jquery-rails'
gem 'jquery-ui-rails'

group :production do
  gem 'libv8'
  gem 'therubyracer', "~> 0.10.2"
  gem "newrelic_rpm"
  gem 'exception_notification', git: 'git://github.com/alanjds/exception_notification.git', :require => 'exception_notifier'
end

gem 'sqlite3' # This has to be active in both modes

group :development do
  gem "thin"
end

group :test do
  # Pretty printed test output
  gem 'turn', :require => false
end

Answer 1

Got it working, so I’ll post it here. This is what I had to do:

1. Run gem uninstall rack locally and remove all instances of rack
2. Add gem "rack", "1.4.1" to my Gemfile (note this is the one it said it already loaded)
3. Run bundle update locally
4. Deploy

Now it works!