Ruby on Rails console is hanging when loading

162
votes

For whatever reason, the Ruby on Rails console refuses to start; it just hangs. I haven't made any changes to my code, and other projects using the same version of Ruby and Ruby on Rails have no issue. When I finally Ctrl + C I get this stack trace, which points to Spring.

I can't explain why this is happening from one moment to the next, where it was working fine. I have cleared out all the gems through RVM and reinstalled all through bundle command, but still no luck. Any ideas would be appreciated.

Also the Ruby on Rails server has no issue so as far as I can tell. The issue is project related, however no code has changed, and it's only the Ruby on Rails console that has the issue.

Ruby 2.1.2
Rails 4.1.4

user_a@ubuntu:~/work/app_a$ rails console
^C/home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/run.rb:54:in `gets': Interrupt
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/run.rb:54:in `verify_server_version'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/run.rb:25:in `call'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/rails.rb:23:in `call'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client.rb:26:in `run'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/bin/spring:48:in `<top (required)>'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `load'
    from /home/user_a/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `<top (required)>'
    from /home/user_a/work/app_a/bin/spring:16:in `require'
    from /home/user_a/work/app_a/bin/spring:16:in `<top (required)>'
    from bin/rails:3:in `load'
    from bin/rails:3:in `<main>'

user_a@ubuntu:~/work/app_a$
5
ruby-on-railsrubyconsole

5 Answers

452
votes

Restarting Spring should fix the hanging commands:

$ bin/spring stop

I experienced hanging commands (rake, bin/rails, etc.) after deleting and recreating a new Ruby on Rails application. Google wasn't that helpful. I hope this is.

Spring will start automatically when you re-run your command.

7
votes

It's something wrong with the Spring gem version I guess.

Go to your Gemfile and comment gem 'spring'. Then run bundle install and try again.

# gem 'spring'

And then:

bundle install

If your work depends on the gem, try update the gems by:

bundle update
3
votes

If $ bin/spring stop doesn't solve the issue, then check to make sure there isn't an orphaned Spring process still hanging around:

$ ps aux | grep -i spring

If you see something like

user  7163  0.0  0.0 110356  2165 pts/3    S+   19:40   0:00 grep --color=auto -i spring
user 16980  0.0  0.4 398826 17580 ?        Sl   Aug31   0:00 spring server | current | started 277 hours ago

then kill the errant spring process and try to start the console again:

$ kill -9 16980 
$ rails c
2
votes

When it is suspected that Spring is the cause of weirdness, try to run this command:

spring stop && spring start
2
votes

Changing the following method in the lib/application.rb file of the spring gem (path can be shown with the gem info spring command) like this does the trick:

def eager_preload
      with_pty do
        # we can't see stderr and there could be issues when it's overflown
        # see https://github.com/rails/spring/issues/396
        STDERR.reopen("/dev/null")
        preload
      end
end

see https://github.com/markiz/spring/commit/5f3ab734fc45d541aaaccb05b59cd95aa49fe8ef