Fix asset_hashing assets affected by Rack middleware or mounted apps (like sprockets). Fixes #558

middleman-core/lib/middleman-core/cli/build.rb

@@ -99,10 +99,7 @@ module Middleman::Cli
       #
       # @return [Rack::Test::Session]
       def shared_rack
-        @_shared_rack ||= begin
-          mock = ::Rack::MockSession.new(shared_server.to_rack_app)
-          ::Rack::Test::Session.new(mock)
-        end
+        @_shared_rack ||= ::Rack::Test::Session.new(shared_server.to_rack_app)
       end
 
       # Set the root path to the Middleman::Application's root

middleman-core/lib/middleman-core/core_extensions/request.rb

@@ -37,7 +37,6 @@ module Middleman
         # @private
         def reset!
           @app = nil
-          @prototype = nil
         end
 
         # The shared Rack instance being build
@@ -94,7 +93,8 @@ module Middleman
         # @private
         # @return [Rack::Builder]
         def prototype
-          @prototype ||= to_rack_app
+          reset!
+          to_rack_app
         end
 
         # Call prototype, use in config.ru