weird.rb

require 'active_record'
require 'minitest/autorun'
require 'logger'

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :event_kinds do |t|
    t.string :name
  end

  create_table :events do |t|
    t.integer :kind_id
  end
end

class EventKind < ActiveRecord::Base
  has_many :events
end

class Event < ActiveRecord::Base
  belongs_to :kind, class_name: "EventKind"
end

class BugTest < MiniTest::Unit::TestCase
  def test_merge_stuff
    puts Event.joins(:kind).merge(EventKind.where(name: "party")).to_sql
    # SELECT "events".* FROM "events"
    #   INNER JOIN "event_kinds" ON "event_kinds"."id" = "events"."kind_id"
    #   WHERE "event_kinds"."name" = 'party'

    puts Event.joins(:kind).merge(EventKind.order(:name)).to_sql
    # SELECT "events".* FROM "events"
    #   INNER JOIN "event_kinds" ON "event_kinds"."id" = "events"."kind_id"
    #   ORDER BY "event_kinds"."name" ASC

    puts Event.joins(:kind).merge(EventKind.order(name: :desc)).to_sql
    # SELECT "events".* FROM "events"
    #   INNER JOIN "event_kinds" ON "event_kinds"."id" = "events"."kind_id"
    #   ORDER BY "events"."name" DESC
  end
end