I\'m using Ruby 2.0.0-p247 and Rails 4.0.0
If I make a minimal Rails 4 site like this:
rails new minimal
cd minimal
rails g
While I was writing up this question I came across this blog post which suggests it is a bug.
http://railsblog.kieser.net/2013/08/rails4-phusion-passenger-asset-pipeline.html
Of the various suggestions, just setting the compilation fallback true...
config.assets.compile = true
seems to be sufficient to kick Rails in to generating appropriately digested URLs:
The other suggestion, explicitly setting RAILS_ENV and RAILS_GROUPS seemed to produce different digest strings on the precompiled files, but they always seem to match up with the generated HTML regardless.