bundle exec rails new が失敗する

ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin13.0]
rbenv 0.4.0
Rails 4.1.0
gem 2.2.2 

gem list
sprockets (2.12.1, 2.11.0)
sprockets-rails (2.1.3)

bundle initしてGemfileのrailsのコメントを外してbundle exec rails newするとbundle installまで来て失敗します。

shell

Resolving dependencies...
Bundler could not find compatible versions for gem "sprockets":
  In snapshot (Gemfile.lock):
    sprockets (2.12.1)

  In Gemfile:
    sass-rails (~> 4.0.3) ruby depends on
      sprockets (<= 2.11.0, ~> 2.8) ruby

Running `bundle update` will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.
         run  bundle exec spring binstub --all
/Users/yom/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.6.2/lib/bundler/resolver.rb:228:in `resolve_for_conflict': Bundler could not find compatible versions for gem "sprockets": (Bundler::VersionConflict)
  In snapshot (Gemfile.lock):
    sprockets (2.12.1)

  In Gemfile:
    sass-rails (~> 4.0.3) ruby depends on
      sprockets (<= 2.11.0, ~> 2.8) ruby

Running `bundle update` will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.

Gemfile.lockにsprockets (2.12.1)を書き込んでるのは誰なんだろう？

深追いしてないけどとりあえずnewする際にbundle installをスキップしてlockを消してから手動でbundle installすれば通ります。

shell

$ bundle exec rails new . --skip-bundle
$ rm Gemfile.lock
$ bundle install

Gemfile.lock

    sass-rails (4.0.3)
      railties (>= 4.0.0, < 5.0)
      sass (~> 3.2.0)
      sprockets (~> 2.8, <= 2.11.0)
      sprockets-rails (~> 2.0)
    sprockets (2.11.0)
      hike (~> 1.2)
      multi_json (~> 1.0)
      rack (~> 1.0)
      tilt (~> 1.1, != 1.3.0)