07 Oct 2010 – Balitmore, MD

Problem:

My subscription does not have a subscriber.
InheritedResources is not populating the `belongs_to` item.

  SubscriptionsController << InheritedResources::Base

    belongs_to :subscriber
    load_and_authorize_resource
    def create
      @subscription = build_resource
      # do something with subscription
      create!
    end
  end

In `def create`, `@subscription.subscriber` is nil. This should be populated by InheritedResources during #build_resource.

  def build_resource
    get_resource_ivar || set_resource_ivar(end_of_association_chain.send(method_for_build, params[resource_instance_name] || {}))
  end

Unfortunately, Cancan’s load_resource is populating the @subscription instance var, so build_resource simply returns the value of the instance var (get_resource_var).

Solution:

Don’t ask cancan to load the resource.

  SubscriptionsController << InheritedResources::Base
    belongs_to :subscriber
    authorize_resource
    def create
      @subscription = build_resource
    # do something with subscription
      create!
    end
  end

Or…

  SubscriptionsController << InheritedResources::Base
    belongs_to :subscriber
    def create
      @subscription = build_resource
      authorize! :create, Subscription
    # do something with subscription
      create!
    end
  end

Note: this appears to only be an issue if using nested routes.

resources :subscriber do
  resources :subscription

This was identified on Rails 3. May affect Rails 2.