Hi,

An embedded collection used in conjunction with class inheritance produce a nil error for some documents in our database (not all):

• undefined method `[]' for nil:NilClass
  when accessed. There is data in the database for the embedded collection and it looks OK. It only does this for a minority of the documents. Please let me know if you have any tips on how to debug this.

The embedded collection use inheritance like this:

class CacheBase
  include Mongoid::Document
  include Mongoid::Timestamps

  embedded_in :cachebase_cacheable, polymorphic: true
end

class A < CacheBase

end

class C
  include Mongoid::Document
  include Mongoid::Timestamps

   embeds_many :a_interactions, :class_name => "A", as: :cachebase_cacheable

end

Please let me know if you have any tips on how to debug this or what the cause may be.