将ActiveModel :: Serializer从v0.9.2迁移到0.8，has_many没有被序列化

Question

I have the following ActiveModel::Serializer class

class MyThingySerializer < ActiveModel::Serializer
  root false

  attributes :id, :name, :description

  has_many :whatsits, embed_namespace: :_embedded

  delegate :whatsits, to: :object

end

It was working fine under AMS 0.9.2 but, in order to add an optional attribute using the include_attributename? mechanism I was told to roll-back to AMS 0.8

Now my whatsits don't appear in my serialised output under the _embedded attribute.

Is there something special I need to do to get my embedded whatsits back?

Update

I've tried adding the following method to my Serializer:

def whatsits
  associated = self.class._associations[:whatsits]
  associated.options[:root] = associated.options[:embed_namespace]
  associated.options[:embed] = :objects
  associated.options[:include] = true
  object.whatsits
end

Hoping that would get the Serializer to emit the whatsits list under the _embedded key, but alas that didn't work..

Answer 1

This works.

class MyThingySerializer < ActiveModel::Serializer
  root false

  attributes :id, :name, :description, :_embedded

  # force the whatsits list to sit under '_embedded'.
  def _embedded
    {
      whatsits: object. whatsits.map {|whatsit| WhatsitSerializer.new(whatsit) } || []
    }
  end
end