cannot use Destroyable because destruction was requested

[flxinxout]

Hello,

Yesterday, I encountered something non deterministic with destroying subscribers. I have a subscriber that I instantiate and then destroy after a task. Then, maybe 3 minutes later, I did the same thing and got the issue that you saw in the title.

My code is the following

from task_execution.command.command import *
import os
import cv2
from cv_bridge import CvBridge
from sensor_msgs.msg import CompressedImage
from rclpy.qos import QoSProfile, QoSReliabilityPolicy, QoSHistoryPolicy, QoSDurabilityPolicy

class TakePicture(Command):
    def __init__(self, path_images, name_task, executor):
        super().__init__()
        self.path_images = path_images
        self.name_task = name_task
        self.image = None
        self.executor = executor
        self.br = CvBridge()
        
        self.qos_profile = QoSProfile(
            reliability=QoSReliabilityPolicy.BEST_EFFORT, 
            durability=QoSDurabilityPolicy.VOLATILE, 
            history=QoSHistoryPolicy.KEEP_LAST,
            depth=1,
        )
        
        self.sub_camera = self.executor.create_subscription(
            CompressedImage, "/ROVER/feed_camera_hd_0", self.take_picture, qos_profile=self.qos_profile)

    def execute(self):
        
        current_frame = self.br.compressed_imgmsg_to_cv2(self.image)
        name = self.name_task + str(time.strftime("%Y-%m-%d_%H:%M:%S", time.localtime())) + '.png'
        image_dir  = os.path.join(
            '/home/xplore/dev_ws/photos_competition',
            self.path_images
        )
        os.makedirs(image_dir, exist_ok=True)

        image_path = os.path.join(image_dir, name)            
        cv2.imwrite(image_path, current_frame)
        
        self.executor.destroy_subscription(self.sub_camera)
        #self.sub_camera = None

    def take_picture(self, image):
        self.image = image

So in summary, I instantiate TakePicture() and call execute() one time and it works well. And then sometimes, when I do the same thing another time, so instantiate TakePicture() and call execute(), I got the error.

[flxinxout]

up :)