output.txt

c@luna /var/www/repos/test_before_save $ rails c
Loading development environment (Rails 3.2.13)
1.9.3p327 :001 > User.new.save
   (0.0ms)  begin transaction
   (0.0ms)  rollback transaction
RuntimeError: Kaboom!
        from /var/www/repos/test_before_save/app/models/user.rb:6:in `bomb'
        from /usr/local/rvm/gems/ruby-1.9.3-p327-perf/gems/activesupport-3.2.13/lib/active_support/callbacks.rb:407:in `_run__4317644355368665104__save__697132430908302071__callbacks'
    # ...

user.rb

class User < ActiveRecord::Base
  # attr_accessible :title, :body
  before_save :bomb

  def bomb
    raise "Kaboom!"
  end
end