Could not find diff-lcs when running generate rspec:install

Question

I am a Django guy new to Rails. I'm trying to get rspec-rails working for me but when I run

$ bundle exec rails generate rspec:install

I get..

Could not find diff-lcs-1.2.5 in any of the sources
Run `bundle install` to install missing gems.

Which is bothersome because

diff-lcs (1.2.5)

is alive and well in Gemfile.lock I have deleted Gemfile.lock and rerun bundle to no avail. I added gem 'diff-lcs' into my Gemfile too.

This is the way I have rspec rails in my gemfile

group :development, :test do
  gem 'rspec-rails'
end

Any tips?

Answer 1

Killing the spring processes took care of it for me, as described at https://jasonplayne.com/web-dev/rails-generate-could-not-find-in-any-of-the-sources. I see that use of the spring loader was added in Rails 4.1, but I'm curious about the interaction here and what can be done to address this problem without having to kill spring.