Test failures: subscription already associated with a wait set

[christophfroehlich]

[INFO] [1713388339.950896541] [test_joint_group_velocity_controller]: activate successful
unknown file: Failure
C++ exception with description "subscription already associated with a wait set" thrown in the test body.

in rolling builds
https://github.com/ros-controls/ros2_controllers/actions/runs/8728644425/job/23948909083?pr=1100
and in debian source build
https://github.com/ros-controls/ros2_controllers/actions/runs/8728644426/job/23948908730

might be related to ros2/rclcpp#2142

[christophfroehlich]

👀 @bmagyar they confirmed in the linked PR that this is not possible any more. You said you have a different approach for the test structure?

[christophfroehlich]

@dhood as you brought yourself into the topic, do you maybe have an idea how to fix that temporarily?

[dhood]

yes, curiosity got the better of me, I'm a sucker for CI that needs troubleshooting 😇

Perhaps explicitly removing the subscription from the waitset after it's been waited on, in wait_for? might be hanging onto a reference by the time the spin_some gets called. I opened #1106 hoping it would run CI for me but no such luck.

Otherwise an alternate approach to avoid waitsets could be an async wait on the underlying rt_command_ptr_ to be set away from null (in combination with spin_until_future_complete), but not as nice. Maybe something else is possible with the default callback group of the node not having that parameter true that William mentioned, but I imagine it would affect something else on those nodes accidentally..?