rails/rails — pull request #7866 by ndbroadbent (2012-10-07 01:22:09+00:00)
Title: Detect asset changes by saving source_digests in manifest.yml, and speed up non-digest assets

Please see the Rails 4 pull request on sprockets-rails for more information: https://github.com/rails/sprockets-rails/pull/21

This is a backport of the work for Rails 3.2. Please note that a new version of sprockets will need to be released (`2.1.4`), with this commit: https://github.com/ndbroadbent/sprockets/commit/82cc1de7e2164c8e96052c612179bb397ccd9a39 (from my [rails3_assets_speedup](https://github.com/ndbroadbent/sprockets/tree/rails3_assets_speedup) branch)