Empty string added to `Gem.path` when running rails server

[noniq]

In a vanilla Rails 4.1 application, an emtpy string is added to Gem.path when running the rails server.

To reproduce: Add p Gem.path at the end of config/application.rb and then start the server with bin/rails s.

The emtpy string is not present when inspecting Gem.path in the Rails console. The empty string also disappears if the spring gem is commented out in the Gemfile.

I’m not sure if an emtpy string is a valid gem path; but I noticed that it causes problems with the better_errors gem: BetterErrors/better_errors#252

The application's Gemfile.lock looks like this: https://gist.github.com/noniq/a0f7e5f19cb544c88065

[noniq]

Okay, so this only happens if the the rails server is started with bundle exec rails server (and not with the rails binstub). Obviously, if there is a binstub present, it should be used for starting the server. However, I still think this behaviour is a bug (not a serious one, though): Using bundle exec with a springified application should not cause an emtpy string to be added to Gem.path.

Steps to reproduce:

rails _4.1.4_ new gempathtest && cd gempathtest
sed -ie "s/# root 'welcome#index'/root 'welcome#index'/" config/routes.rb 
echo "class WelcomeController < ApplicationController; def index; render text: Gem.path.inspect; end; end" >app/controllers/welcome_controller.rb
bundle exec rails server # emtpy gem path does not appear when using `bin/rails server` 

# In another terminal window:
curl localhost:3000
# => ["/Users/stefan/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0", "/Users/stefan/.gem/ruby/2.1.0", ""]

[achempion]

don't sure, but maybe #297 will similar

[jonleighton]

Fixed 666db7d