Detect modified assets in a gemified rails engine

assets.rake

task :fix_precompile_hook do
  module Fixassets
    module Assets
      extend ActiveSupport::Concern
      included do
        def dependency_fresh_with_path_fix?(environment, dep)
          path = dep.pathname.to_s
          return false unless environment.paths.find { |env_path| path.starts_with? env_path }
          dependency_fresh_without_path_fix?(environment, dep)
        end

        alias_method_chain :dependency_fresh?, :path_fix
      end
    end
  end
  Sprockets::Asset.send(:include, Fixassets::Assets)
end

task "assets:precompile" => :fix_precompile_hook