Hobo::Model::Lifecycles::Transition is probably buggy

lifecycle_sample.rb

# Consider a program managing tasks, each reservable by an author and a reviewer.
# The author and the reviewer of one task must not be the same
#
transition :reserve, { :available => :reserved }, :available_to => :users,
                                                  :user_becomes => :author,
                                                  :if => Proc.new { |task| task.acting_user != task.reviewer }

patch_hobo_lifecycle_transition.rb

Hobo::Model::Lifecycles::Transition.class_eval do

  def run!(record, user, attributes)
    current_state = record.lifecycle.state_name
    unless start_states.include?(current_state)
      raise Hobo::Model::Lifecycles::LifecycleError, "Transition #{record.class}##{name} cannot be run from the '#{current_state}' state"
    end
    ActiveRecord::Base.transaction do   #  <--- I enclosed the transition to
      record.lifecycle.active_step = self     # avoid incomplete runs
      record.with_acting_user(user) do
        # <------------------------------------ I moved `prepare!(record, attributes)` from outside of
        if can_run?(record)                   # this `if can_run?(record)` check to it's true execution path
          prepare!(record, attributes)        # because `prepare!` updates a critical attribute if the
          if change_state(record)             # transition demands e.g. `:user_becomes => :author` what could
            fire_event(record, on_transition) # interfere with guards like `author.nil?`. If such thing would
          end                                 # happen, the transition would raise a Hobo::PermissionDeniedError
        else                                  # exception.
          raise Hobo::PermissionDeniedError
        end
      end
    end # transaction
  end

end