Userdata change type

edit

Hi,

I try to du a small smach tree and pass a class between the state with userdata, the code look like this

class Auto_move_info(object):
        __pallet_position = None
        __pallet_place_position = None

    def __init__(self, pallet_position=None, pallet_place_position=None):
        self.__pallet_position = pallet_position
        self.__pallet_place_position = pallet_place_position

    def set_pallet_position(self, pallet_position):
        self.__pallet_position = pallet_position

    def get_pallet_position(self):
        return self.__pallet_position

    def set_pallet_place_position(self, pallet_place_position):
        self.__pallet_place_position = pallet_place_position

    def get_pallet_place_position(self):
        return self.__pallet_place_position

class Get_pallet_position(smach.State):
    def __init__(self):
        smach.State.__init__(self, outcomes=['pallet_position_found'],
                            output_keys=['get_pallet_position_op'])
        self.move_pallet_A_to_X = Auto_move_info('A','X')

    def execute(self, userdata):
        time.sleep(2)   
        userdata.get_pallet_position_op = self.move_pallet_A_to_X
        print ("1")
        print(self.move_pallet_A_to_X)
        print ("2")
        rospy.loginfo('Get_pallet_position')
        return 'pallet_position_found'

class Calculate_pallet_position(smach.State):
    def __init__(self):
        smach.State.__init__(self, outcomes=['calculation_pallet_done'],
                            input_keys=['calculate_pallet_position_ip'],
                            output_keys=['calculate_pallet_position_op'])

    def execute(self, userdata):
        time.sleep(2)
        print ("3")
        print(userdata.calculate_pallet_position_ip)
        print ("4")
        rospy.loginfo('Executing state Calculate_pallet_position')
        return 'calculation_pallet_done'

The result the become:

[INFO] [WallTime: 1476091443.061490] State machine starting in initial state 'Get_pallet_position' with userdata: 
    []
1
<class_definition.Auto_move_info object at 0xb59ced2c>
2
[INFO] [WallTime: 1476091445.064946] Get_pallet_position
[INFO] [WallTime: 1476091445.065734] State machine transitioning 'Get_pallet_position':'pallet_position_found'-->'Calculate_pallet_position'
3
<smach.user_data.Const object at 0xb6158b4c>
4
[INFO] [WallTime: 1476091447.070927] Executing state Calculate_pallet_position

Why does the object move_pallet_A_to_X change from an Auto_move_info object to a Const?