"Assets should not be requested directly" - Rails 4.2.0.beta4

[radar]

I'm seeing this error with Rails 4.2.0.beta4 and bootstrap-sass 3.3.0.1:

Sprockets::Rails::Environment::NoDigestError (Assets should not be requested directly without their digests: Use the helpers in ActionView::Helpers to request bootstrap):
  sprockets-rails (3.0.0.beta1) lib/sprockets/rails/environment.rb:22:in `call'
  actionpack (4.2.0.beta4) lib/action_dispatch/routing/mapper.rb:51:in `serve'
  actionpack (4.2.0.beta4) lib/action_dispatch/journey/router.rb:43:in `block in serve'
  actionpack (4.2.0.beta4) lib/action_dispatch/journey/router.rb:30:in `each'
  actionpack (4.2.0.beta4) lib/action_dispatch/journey/router.rb:30:in `serve'
  actionpack (4.2.0.beta4) lib/action_dispatch/routing/route_set.rb:780:in `call'

I have an application to reproduce this problem called "ticketee" at https://github.com/railsbook/rails_4_in_action_examples/tree/bootstrap-wip. Start up the application and try navigating to any page. This error should appear in the console.

(P.S. Yes we are going to include Bootstrap in Rails 4 in Action.)

[glebm]

Was caused by the wrong extension: application.css instead of application.css.sass, rubysherpas/r4ia_examples_old#1 (comment)

[radar]

Well that's incredibly dumb of me. The 4 hours of tech reviewing must've turned my brain to mush. Thanks @glebm!

[glebm]

@radar Lots of users make this mistake, I think Rails is a bit weird for generating .css by default.