Testing non-persistent fields on persisted identity-mapped entity instances in JRuby and Sequel through jdbc-postgres

non_persistent_test.rb

#! /usr/bin/env jruby

require 'rubygems'
require 'sequel'

gem 'jdbc-postgres'

@connection = Sequel.connect('jdbc:postgresql://localhost:5432/test?user=test&password=test')
Sequel::Model.db = @connection
Sequel::Model.plugin :identity_map
module Sequel
  class Model
    module ClassMethods
      def implicit_table_name
        underscore(demodulize(name)).to_sym
      end
    end
  end
end

Sequel::Model.db.create_table! :test do
  primary_key :id
  foreign_key :parent_id, :test, :on_delete => :set_null
  index :name

  String  :name
  String  :object_type, :null => false
end unless Sequel::Model.db.table_exists? :test

class Test < Sequel::Model
  plugin :identity_map
  plugin :rcte_tree
  plugin :single_table_inheritance, :object_type

  def non_persistent_stuff
    @non_persistent_stuff ||= []
  end

  def to_s
    "#{name} <object_id:#{object_id},entity_id:#{id}>"
  end
end

a = Test.find_or_create(:name => 'A')
b = nil
c = nil

t0 = Thread.new do
  b = Test.find_or_create(:name => 'B')
  c = Test.find_or_create(:name => 'C')

  a.add_child b

  puts "a.children.include? b # => #{a.children.include? b}"
  b.non_persistent_stuff << c
  puts ""
  puts "b (should be 'B') # => #{b}"
  puts "b.non_persistent_stuff # => [#{b.non_persistent_stuff}]"
  puts "b.non_persistent_stuff.include? c # => #{b.non_persistent_stuff.include? c}"
end

t0.join

puts ""

t1 = Thread.new do
  x = Test.find(:name => 'A')
  y = x.children.first
  z = Test.find(:name => 'C')
  puts "x (should be 'A') # => #{x}"
  puts "z (should be 'C') # => #{z}"
  puts "x.children.include? b # => #{a.children.include? b}"
  puts ""
  puts "b (should be 'B') # => #{b}"
  puts "y (should be 'B') # => #{y}"
  puts ""
  puts "b == y (should be true) # => #{b == y}"
  puts "b.object_id == y.object_id (shouldn't this be true? perhaps I don't understand what an identity map does) # => #{b.object_id == y.object_id}"
  puts ""
  puts "y.non_persistent_stuff # => [#{y.non_persistent_stuff}]"
  puts "y.non_persistent_stuff.include? z # => #{y.non_persistent_stuff.include? z}"
end

t1.join

Sequel::Model.db.drop_table :test if Sequel::Model.db.table_exists? :test