Gem Load Error is: superclass must be a Class (Module given)

[skozz]

Hi, before of all sorry for the hassle.

I'm getting this error just after install the gem into my Rails project. Steps:

1. Added the gem to the gemfile
2. bundle install
3. run rails

/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:94:in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'slack-ruby-client'. (Bundler::GemRequireError)
Gem Load Error is: superclass must be a Class (Module given)
Backtrace for gem load error is:
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack/web/api/error.rb:4:in `<module:Api>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack/web/api/error.rb:3:in `<module:Web>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack/web/api/error.rb:2:in `<module:Slack>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack/web/api/error.rb:1:in `<top (required)>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack-ruby-client.rb:21:in `require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/slack-ruby-client-0.7.7/lib/slack-ruby-client.rb:21:in `<top (required)>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:91:in `require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:91:in `block (2 levels) in require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:86:in `each'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:86:in `block in require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:75:in `each'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:75:in `require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler.rb:106:in `require'
/Users/skozz/www/rails-application/api/config/application.rb:16:in `<top (required)>'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:141:in `require'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:141:in `require_application_and_environment!'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:67:in `console'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
/Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands.rb:17:in `<top (required)>'
bin/rails:4:in `require'
bin/rails:4:in `<main>'
Bundler Error Backtrace:
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:90:in `block (2 levels) in require'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:86:in `each'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:86:in `block in require'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:75:in `each'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler/runtime.rb:75:in `require'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/bundler-1.13.6/lib/bundler.rb:106:in `require'
  from /Users/skozz/www/rails-application/api/config/application.rb:16:in `<top (required)>'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:141:in `require'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:141:in `require_application_and_environment!'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:67:in `console'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
  from /Users/skozz/.rvm/gems/ruby-2.1.7@rails-project/gems/railties-4.2.7.1/lib/rails/commands.rb:17:in `<top (required)>'
  from bin/rails:4:in `require'
  from bin/rails:4:in `<main>'

Ruby 2.1.7 Rails 4.2.7

Someone have any idea?

[skozz]

Update: changing class Error < ::Faraday::Error by class Error inside of the gem now I can run my rails app and continuing developing my slack bot, but of course is not the best way.

[dblock]

Do you have some global class Error somewhere? Any references to Faraday::Error? Any monkey patches? Faraday::Error is definitely a class (see https://github.com/lostisland/faraday/blob/master/lib/faraday/error.rb), so it looks like it thinks Faraday::Error is a module?

[skozz]

@dblock makes sense. It's a big rails project, let me check the code and I'll back with the answer. Thank you!

[Umofomia]

@skozz I see this is an old issue, but just wanted to note that the root cause is likely due to the fact that Faraday::Error used to be defined as a module, but it was changed in lostisland/faraday#204 to become a class in starting with version 0.9.0.

You need to make sure you're using a version of Faraday newer than 0.9.0 to make this work.