mongoid - git bisect FTW!

fields_inheritance_fix.rb

#!/usr/bin/env ruby

$:.unshift File.join File.dirname(__FILE__), "lib"

require 'mongoid.rb'

class Shape
  include Mongoid::Document
  field :x, type: Integer, default: 0
  field :y, type: Integer, default: 0
end

class Circle < Shape
  field :radius, type: Integer, default: 0
end

class Square < Shape
  field :width, type: Integer, default: 0
  field :height, type: Integer, default: 0
end

exit Square.fields.keys.include?('radius') ? 1 : 0