Mailcatcherがエラーで起動しない対処メモ

事象

• メールキャッチャーを起動しようとしたらエラーがでて上がりません

$ mailcatcher
/usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- concurrent (LoadError)
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/activesupport-4.2.7.rc1/lib/active_support/logger_thread_safe_level.rb:2:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/activesupport-4.2.7.rc1/lib/active_support/logger.rb:3:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/activesupport-4.2.7.rc1/lib/active_support.rb:27:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/activesupport-4.2.7.rc1/lib/active_support/all.rb:1:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/mailcatcher-0.6.4/lib/mail_catcher.rb:16:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/gems/mailcatcher-0.6.4/bin/mailcatcher:3:in `<top (required)>'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/bin/mailcatcher:23:in `load'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/bin/mailcatcher:23:in `<main>'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/bin/ruby_executable_hooks:15:in `eval'
        from /usr/local/rvm/gems/ruby-2.2.3@mailcatcher3/bin/ruby_executable_hooks:15:in `<main>'

原因

• 依存ライブラリのバージョンの問題のようです
  • activesupportのrcが入ってきてしまっている

対処

• 下記であがるようになりました

gem uninstall activesupport -v 4.2.7.rc1
gem install activesupport -v 4.2.6