`KeyboardInterrupt` exception on shutdown

[Timple]

Description

KeyboardInterrupt exception on shutdown

Expected Behavior

Clean shutdown

Actual Behavior

[relay_field-69] Traceback (most recent call last):
[relay_field-69]   File "/opt/ros/iron/lib/topic_tools/relay_field", line 33, in <module>
[relay_field-69]     sys.exit(load_entry_point('topic-tools==1.2.0', 'console_scripts', 'relay_field')())
[relay_field-69]   File "/opt/ros/iron/lib/python3.10/site-packages/topic_tools/relay_field.py", line 226, in main
[relay_field-69]     node.destroy_node()
[relay_field-69]   File "/opt/ros/iron/lib/python3.10/site-packages/rclpy/node.py", line 1887, in destroy_node
[relay_field-69]     self.__node.destroy_when_not_in_use()
[relay_field-69] KeyboardInterrupt

To Reproduce

** Steps to reproduce the behavior, e.g.

1. ros2 topic pub /chatter std_msgs/String "{}"
2. ros2 run topic_tools relay_field /chatter /chatter2 std_msgs/String "{data: m.data}"
3. Press ctrl+C
4. Watch error

System (please complete the following information)

• OS: Ubuntu
• ROS 2 Distro: Iron

[MichaelOrlov]

Preliminary analysis

The failure is very strange.
It turns out that we already have KeyboardInterrupt handler in the relevant relay_field.py

topic_tools/topic_tools/topic_tools/relay_field.py

Lines 217 to 227 in cefac47

	node = RelayField(args)
	try:
	rclpy.spin(node)
	except KeyboardInterrupt:
	print('relay_field stopped cleanly')
	except BaseException:
	print('exception in relay_field:', file=sys.stderr)
	raise
	finally:
	node.destroy_node()
	rclpy.shutdown()

Also according to the call stack, the failure happened inside node.destroy_node() call on the self.__node.destroy_when_not_in_use().

It might be that SIGINT arrived twice. i.e., the second time when we were already in the final stage in the self.__node.destroy_when_not_in_use(). Need to reproduce and debug this issue.