mongoid-collection-snapshot-nil.rb

require 'mongoid'
require 'mongoid-collection-snapshot'

Mongo::Logger.logger.level = Logger::INFO

Mongoid.connect_to 'widgets-and-gadgets', max_pool_size: 16

class Widget
  include Mongoid::Document
end

class Gadget
  include Mongoid::Document
end

class WidgetsAndGadgets
  include Mongoid::CollectionSnapshot

  document do
    belongs_to :widget, inverse_of: nil
    belongs_to :gadget, inverse_of: nil
  end

  def build
    Widget.all.each do |widget|
      Gadget.all.each do |gadget|
        next unless Random.rand(2) == 1
        collection_snapshot.insert_one(widget_id: widget.id, gadget_id: gadget.id)
      end
    end
  end
end

Widget.delete_all
Gadget.delete_all

10.times do
  Widget.create!
  Gadget.create!
end

WidgetsAndGadgets.create!

require 'thread'

workers = (0...8).map do
  Thread.new do
    begin
      while true
        STDOUT.write "."
        WidgetsAndGadgets.latest.documents.each do |pair|
          raise "got a nil widget" unless pair.widget
          raise "got a nil gadget" unless pair.gadget
        end
      end
    rescue ThreadError
    end
  end
end

workers.map(&:join)

puts " done."