#!/usr/bin/env ruby

require 'logger'
require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem "mongoid", "#{ENV["MONGOID_VERSION"] || '8.0.10'}"
  gem "debug", "~> 1.7"
  gem "minitest", require: "minitest/autorun"
end

require 'mongoid'

Mongoid.configure { |c| c.clients.default = { hosts: ['localhost'], database: 'test' } }
puts Mongoid::VERSION

class Address
  include Mongoid::Document
  include Mongoid::Attributes::Dynamic
  field :city, type: String, default: "Unknown"
  embedded_in :person
end

class Person
  include Mongoid::Document
  field :name, type: String
  embeds_many :addresses
end

Person.delete_all
Address.delete_all

p = Person.create!(name: "John")
result = Person.collection.find(:_id => p.id)
        .update_one({:$push => {:addresses => {:_id => BSON::ObjectId.new}}})
p1 = Person.find(p.id)
p1[:addresses].is_a?(Array)
puts p1.addresses[0].changes.inspect # {"city"=>[nil, "Unknown"]}
puts p1.changes.inspect # {"addresses"=>[[{"_id"=>BSON::ObjectId('68d2c593fa49abf8f51c1cad')}], [{"_id"=>BSON::ObjectId('68d2c593fa49abf8f51c1cad'), "city"=>"Unknown"}]]}
p1.save! # [40]: Updating the path 'addresses.0.city' would create a conflict at 'addresses' (on localhost, legacy retry, attempt 1) (Mongo::Error::OperationFailure)