Wolfgang Barth PRO said over 6 years ago on Polymorphic Associations :

I like it, routing via :modules is very elegant. It works for me in a normal rails application, but i can't get it work inside of a rails engine.

config/routes.rb from the engine:

Wobauth::Engine.routes.draw do
  resources :users do
    resources :authorities, module: :users
  end
end

Controllers:

module Wobauth
  class Users::AuthoritiesController < AuthoritiesController ...
  end
end
module Wobauth
  class AuthoritiesController < ApplicationController
   ...
  end
end

I get the following error:

uninitialized constant Authority
Extracted source (around line #269):
      names.inject(Object) do |constant, name|
        if constant == Object
          constant.const_get(name)
        else
          candidate = constant.const_get(name)
          next candidate if constant.const_defined?(name, false)

It works without specifying :modules, but this means i must place the logic in the main authorities_controller ... so its less elegant. Any idea?

Wolfgang.