Issues with asset digest fingerprinting (with fix)

I'm looking to get some more feedback on an issue (and fix) I posted
here: https://github.com/rails/rails/issues/2294.

TLDR; asset fingerprinting causes issues in production mode with
certain javascript libraries due to dynamic file loading. Notably the
major editors (TinyMCE, CKEditor, etc) but smaller libraries can be
affected too. My fix allows for certain paths to be excluded from
fingerprinting or for fingerprinting to be disabled altogether.

An example; let's say I'm building an app and I want to integrate
FancyZoom (https://github.com/jnunemaker/fancy-zoom). I copy the files
into my assets folders (either app/assets or vendor/assets) and
require the javascript in my application.js.

Everything works fine in development mode, but the images won't load
in production, due to the fingerprints appended to the image
filenames. Using the image-url helpers won't help here either - check
the code (https://github.com/jnunemaker/fancy-zoom/blob/master/jquery/
js/fancyzoom.js) and you'll see why.

At this point, I am forced to move the assets into public. I either
move all of the FancyZoom assets together, giving up on including the
library's javascript in my application.js, or I move only the image
files into public.

Either way, assets are now spread between public and app/assets. I
also now have assets located at http://mysite.com/assets as well as
http://mysite.com/fancyzoom. Messy.

Or, if my patches are applied, I add to my config/application.rb:

    config.assets.fingerprinting.exclude << "fancyzoom/*"

and I don't need to do anything else. As seen in my proof of concept
(https://github.com/spohlenz/tinymce-rails/blob/master/lib/tinymce-
rails.rb), gems with assets can do this automatically. The app
developer doesn't need to know about it, it just works.

In my opinion, this is a critical feature to make the asset pipeline
workable. My fix does add some extra options to the Sprockets
environment but I haven't seen a better way of doing it yet.

Thanks,
Sam Pohlenz

I'm not sure what to do about this issue, so I've assigned it to Josh.
Maybe he can chime in.