Ruby on Rails incompatible library

Question

I've just started to have a look at ruby on rails and can't get a server to run. I'm running ruby 2.3.0 and rails 4.2.5 and after I have a new rail projects I try to run bin/rails server but get the following error:

Warning: Running `gem pristine --all` to regenerate your installed gemspecs (and deleting then reinstalling your bundle if you use bundle --path) will improve the startup performance of Spring.
/Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:13:in `require': incompatible library version - /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext/parser.bundle (fatal)
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:13:in `<module:Ext>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:12:in `<module:JSON>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:9:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:58:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:58:in `<module:JSON>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:54:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object/json.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object/json.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object.rb:12:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object.rb:12:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/configuration.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/configuration.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/railtie.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/railtie.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/engine.rb:1:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/engine.rb:1:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/application.rb:7:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/application.rb:7:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails.rb:11:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails.rb:11:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/server.rb:4:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/server.rb:4:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:123:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:73:in `server'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands.rb:17:in `<top (required)>'
    from /Users/John/Developer/Rails/blog/bin/rails:9:in `require'
    from /Users/John/Developer/Rails/blog/bin/rails:9:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/rails.rb:28:in `load'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/rails.rb:28:in `call'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/command.rb:7:in `call'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client.rb:28:in `run'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/bin/spring:51:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/binstub.rb:11:in `load'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/binstub.rb:11:in `<top (required)>'
    from /Users/John/.rvm/rubies/ruby-head/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /Users/John/.rvm/rubies/ruby-head/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /Users/John/Developer/Rails/blog/bin/spring:13:in `<top (required)>'
    from bin/rails:3:in `load'
    from bin/rails:3:in `<main>'

Gem list says that I have json (1.8.3, 1.8.2). I also tried reinstalling rails and updating my ruby version through rvm. Any idea what is wrong? I have tried looking around online but am a bit stuck especially as I have never used rails before and only a little ruby.

Answer 1

Remove vendor and run bundle install could solve this problem. It worked for me.

Answer 2

Something's gotten weird/corrupted in your ruby environment. I'd blame rvm. Personally I am not a fan of rvm.

But you might try gem uninstall json, follow prompts to uninstall ALL versions. Then bundle install again. Then hopefully you'll be fixed up.

Answer 3

I had a similar problem to what you described after I had taken a different ruby version into use (from 2.3.0 -> 2.3.3).

I found that running:

$ gem install bundler

Then:

$ bundle install

... worked a charm for me. This reinstalled all of the packages I needed in my Gemfile without any dependency issues.