Bug: include_data loads association

[richmolj]

Expected behavior vs actual behavior

Given the following serializer:

class PostSerializer < ActiveModel::Serializer
  has_many :comments do
    link :related do
      href "/posts/#{object.id}/comments"
    end
    include_data false
  end
end

This correctly does not include comment relationship data in the response. However, all the comments are still loaded (ie select * from comments where post_id = ?). I would expect this to avoid loading the comments since none of that data is needed in the response.

Steps to reproduce

Any serializer with include_data false, look at the ActiveRecord queries that fire.

Environment

ActiveModelSerializers Version (commit ref if not on tag): master/0165215

Output of ruby -e "puts RUBY_DESCRIPTION": ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin14]

OS Type & Version: OSX 10.10.5 (Yosemite)

Integrated application and version (e.g., Rails, Grape, etc): Rails 5 beta 3

[beauby]

You are right, I've had this one on my radar for a while. Basically we would just need to lazily build the associations from the reflections (plus, this would allow us to tackle the optim on "links-only belongs_to").