load the collection instance variable on index action - closes #137

lib/cancan/ability.rb

@@ -221,6 +221,10 @@ module CanCan
       attributes
     end
 
+    def has_block?(action, subject)
+      relevant_can_definitions(action, subject).any?(&:only_block?)
+    end
+
     private
 
     def unauthorized_message_keys(action, subject)

lib/cancan/controller_resource.rb

@@ -28,6 +28,8 @@ module CanCan
     def load_resource
       if !resource_instance && (parent? || member_action?)
         @controller.instance_variable_set("@#{instance_name}", load_resource_instance)
+      elsif load_collection?
+        @controller.instance_variable_set("@#{instance_name.pluralize}", load_collection)
       end
     end
 
@@ -49,6 +51,16 @@ module CanCan
       end
     end
 
+    def load_collection?
+      !parent? && collection_actions.include?(@params[:action].to_sym) &&
+      resource_base.respond_to?(:accessible_by) &&
+      !@controller.current_ability.has_block?(authorization_action, resource_class)
+    end
+
+    def load_collection
+      resource_base.accessible_by(@controller.current_ability)
+    end
+
     def build_resource
       resource = resource_base.send(@options[:singleton] ? "build_#{name}" : "new")
       initial_attributes.each do |name, value|