Can't activate rack (~> 1.4.0, runtime) already activated rack-1.5.0

Question

I've been looking for an answer to this for over a day now, and searched StackOverflow thoroughly.

I understand the conflict that's happening, and I should just uninstall the version of Rack I don't need, but here's the thing. I'm developing on Koding (http://koding.com) and I don't have access to system level gems.

Rails was working before, I installed the mongo gem, removed it, and installed mysql2 gem.

bash4.1$ rails
/usr/lib/ruby/site_ruby/1.8/rubygems.rb:233:in `activate': can't activate rack (~> 1.4.0, runtime) for ["actionpack-3.2.11", "railties-3.2.11"
], already activated rack-1.5.0 for ["rack-ssl-1.3.2", "railties-3.2.11"] (Gem::LoadError)
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:249:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:248:in `each'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:248:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:249:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:248:in `each'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:248:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:1082:in `
from /usr/bin/rails:18

I've wiped my directory clean, tried using RVM, and still nothing. Any ideas?

Thanks!

Answer 1

Use Bundler to resolve the Rack dependency according to the app Gemfile.

$ bundle exec rails

Otherwise, delete Rack 1.5.0 and retry.

$ gem uninstall rack
# select the proper version to delete