using a lambda for asset_host yields different asset digests for the same file on 4.0.x

[bradrobertson]

This repo roughly explains everything, but a quick synopsis:

If you use a lambda for the asset_host the digests that get generated for assets change on each precompile you run, even though the contents of the file haven't changed. This is an issue because one might deploy to multiple machines and precompile on each of them and they'd all have different digests for the exact same file.

I wasn't sure if this belonged in Rails or Sprockets because asset_host is a Rails thing, but digesting is a Sprockets thing.

I'd be happy to look into the solution if someone could point me in the right direction. I'm not extremely familiar with the Rails/Sprockets codebases.

[matthewd]

rails/sprockets-rails#140