Ruby on Rails console is hanging when loading

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.

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

spring stop && spring start

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

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

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