Merge pull request #2987 from kennyj/master

fix https://github.com/rails/rails/issues/2947 (with testcase)

actionpack/lib/sprockets/assets.rake

@@ -16,6 +16,9 @@ namespace :assets do
       # Always compile files
       Rails.application.config.assets.compile = true
 
+      # Always ignore asset host
+      Rails.application.config.action_controller.asset_host = nil
+
       config = Rails.application.config
       env    = Rails.application.assets
       target = Pathname.new(File.join(Rails.public_path, config.assets.prefix))

railties/test/application/rake_test.rb

@@ -216,5 +216,21 @@ def test_assets_precompile_with_utf8_filename
       end
     end
 
+    def test_assets_precompile_ignore_asset_host
+      add_to_config <<-RUBY
+        config.action_controller.asset_host = Proc.new { |source, request| "http://www.example.com/" }
+      RUBY
+
+      app_file "app/assets/javascripts/test.js.erb", <<-RUBY
+        alert("<%= asset_path "rails.png" %>");
+      RUBY
+
+      Dir.chdir(app_path) do
+        `rake assets:precompile`
+        open("public/assets/application.js") do |f|
+          assert_match(/\"\/assets\/rails.png\"/, f.read)
+        end
+      end
+    end
   end
 end