test_assoc_with_condition.rb

require "rubygems"
gem "activerecord", "3.0.3"
# $:.unshift "../../rails/activerecord/lib"
gem "arel", "2.0.7"
# $:.unshift "../../arel/lib"
require "active_record"

ActiveRecord::Base.establish_connection :adapter => "sqlite3", :database => "test.sqlite3"

ActiveRecord::Base.connection.instance_eval do
  create_table "users", :force => true do |t|
    t.string "name"
  end
  create_table "user_responsibilities", :force => true do |t|
    t.integer "user_id"
    t.integer "responsibility_id"
    t.boolean "active"
  end
  create_table "responsibilities", :force => true do |t|
    t.string "name"
    t.boolean "active"
  end
end

class User < ActiveRecord::Base
  has_many :user_responsibilities, :conditions => {:active => true}
  has_many :responsibilities, :through => :user_responsibilities, :conditions => {:active => true}
end

class UserResponsibility < ActiveRecord::Base
  belongs_to :user
  belongs_to :responsibility
end

class Responsibility < ActiveRecord::Base
  has_many :user_responsibilities
end

puts User.joins(:user_responsibilities).to_sql
# => SELECT "users".* FROM "users"
#     INNER JOIN "user_responsibilities" ON "user_responsibilities"."user_id" = "users"."id" AND "user_responsibilities"."active" = 't'
puts User.joins(:responsibilities).to_sql
# with Rails 3.0.3 (and also 3-0-stable) and Arel 2.0.7
# => SELECT "users".* FROM "users"
#     INNER JOIN "user_responsibilities" ON "users"."id" = "user_responsibilities"."user_id"
#     INNER JOIN "responsibilities" ON 0
# with Rails 3.0.3 (and also 3-0-stable) and Arel master
# => SELECT "users".* FROM "users"
#     INNER JOIN "user_responsibilities" ON "users"."id" = "user_responsibilities"."user_id"
#     INNER JOIN "responsibilities" ON "responsibilities"."active" = 't'
# with Rails master and Arel master
# => SELECT "users".* FROM "users"
#     INNER JOIN "user_responsibilities" "user_responsibilities" ON "users"."id" = "user_responsibilities"."user_id" AND "responsibilities"."active" = 't'
#     INNER JOIN "responsibilities" ON "responsibilities"."id" = "user_responsibilities"."responsibility_id" AND "responsibilities"."active" = 't'