warning: already initialized constant APP_PATH

[janko]

I'm getting a warning: already initialized constant APP_PATH error, coming from bin/rails. I'm using the latest Spring and Rails 4.

[jonleighton]

Did you regenerate your binstubs for Spring 1.1?

[janko]

Yes. I first ran it on 1.0, and then when I upgraded to 1.1 I ran it again just in case (and nothing changed).

[jonleighton]

If nothing changed between 1.0 and 1.1 then something is wrong - the 1.1 binstubs are totally different to 1.0.

[janko]

I get this output on spring binstub --all:

* bin/rake: spring already present
* bin/rspec: spring already present
* bin/rails: spring already present

So, Spring probably saw 1.0 binstubs, and then concluded that binstubs are already present. This is my bin/rails:

#!/usr/bin/env ruby

begin
  load File.expand_path("../spring", __FILE__)
rescue LoadError
end

APP_PATH = File.expand_path('../../config/application',  __FILE__)
require_relative '../config/boot'
require 'rails/commands'

[jonleighton]

Ok, you actually have a 1.1 binstub there, which is why nothing happens. Spring upgrades 1.0 binstubs if they're present.

I'm not sure why this is happening so if you can try to investigate and provide more information that would be helpful as there's not much to go on. Two possible theories are:

• Something else is defining APP_PATH
• The APP_PATH line in your bin/rails is getting run twice for some reason

[janko]

Yes, I'm sorry. So, bin/rails is ran twice. I get it, for example, when I exit the rails server; upon exiting bin/rails is ran again for some reason.

[jonleighton]

Ok, if you stick a puts caller in there we should hopefully see why...

[janko]

On exit the caller is empty. I'm not sure what that means.

[janko]

I tested that it happens with a brand new unchanged Rails 4.0 application, so I don't know why I'm the only one getting this warning.

[jonleighton]

Aha, yes I can repro:

$ bin/rails s
=> Booting WEBrick
=> Rails 4.1.0.rc1 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
=> Ctrl-C to shutdown server
[2014-02-24 08:39:22] INFO  WEBrick 1.3.1
[2014-02-24 08:39:22] INFO  ruby 2.0.0 (2013-06-27) [x86_64-linux]
[2014-02-24 08:39:22] INFO  WEBrick::HTTPServer#start: pid=4278 port=3000
^C[2014-02-24 08:39:26] INFO  going to shutdown ...
[2014-02-24 08:39:26] INFO  WEBrick::HTTPServer#start done.
Exiting
bin/rails:6: warning: already initialized constant APP_PATH
/home/turnip/Code/spring/test/apps/tmp/bin/rails:6: warning: previous definition of APP_PATH was here

Note that the rails server is supposed to bypass spring so that's probably something to do with it. (I don't use rails server so hadn't noticed this myself.)

[janko]

Thank you :)

[felixbuenemann]

Btw. the same error is thrown if there is a LoadError inside config/routes.rb, which is pretty confusing.

[DammersH]

May I add that this error will be thrown even before the server can start?