Installing Rails 4.2.0.beta1 – Bundler could not find compatible versions for gem "sprockets-rails"

Question

I've attempted to install Rails 4.2.0.beta1 (released Aug 20, 2014). I get an error Bundler could not find compatible versions for gem "sprockets-rails". Here are the details:

$ bundle update rails
Fetching gem metadata from https://rubygems.org/.........
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "sprockets-rails":
  In Gemfile:
    sass-rails (~> 4.0.3) ruby depends on
      sprockets-rails (~> 2.0) ruby

    rails (= 4.2.0.beta1) ruby depends on
      sprockets-rails (3.0.0.beta1)

How can I install Rails 4.2.0.beta1?

Answer 1

You have a sass-rails gem in your Gemfile. You need to change the version of sass-rails to '5.0.0.beta1'. And then run bundle update sass-rails rails.

You could find some useful info at this sprockets-rails issue.

P.S.: Moreover I have the same problem with rails_admin which I reported here.