Rails 3.2 Engine Layouts

Question

I\'m struggling to understand how Rails 3.2 applies layouts when using mountable engines.

Scenario: I\'m building an engine which itself has a dashboard view and an

Answer 1

I've debugged the problem and actually it's not a bug in Engines. The problem is caused by the way rails dependencies are loaded.

This code will behave differently in 2 scenarios that you're showing:

module Enginedemo
  class DashboardController < ApplicationController
  end
end

If ApplicationController is already loaded, rails will assume that we just want to use it and you will actually not inherit from Enginedemo::ApplicationController but from ApplicationController. In the other scenario, when you first load engine's controller, ApplicationController is not loaded yet, so Rails does the right thing.

Thankfully this problem occurs only in development environment as in production controllers are loaded when application is booting.

I'm not sure if this is something that can be easily fixed in rails dependencies, I will take a look at it.

For now, please explicitly require application controller:

require 'enginedemo/application_controller'

module Enginedemo
  class DashboardController < ApplicationController
  end
end