SimpleActionServer may call nullprt callback when executing the transition to deactivate #4024
Description
Bug report
The SimpleActionServer may call nullprt callback when executing the transition to deactivate if it is running and no completion callback is set.
Required Info:
- Operating System:
- Ubuntu 20.04
- ROS2 Version:
- ROS2 Iron
- Version or commit hash:
- Latest Iron branch
- DDS implementation:
- cycloneDDS
Steps to reproduce issue
Call lifecycle service transition "deactivate" when a lifecycle node with a simple action server is running.
Expected behavior
The SimpleActionServer doesn't call any callback.
Actual behavior
The SimpleActionServer does call a nullprt callback creating bad_function_call exception and the transition fails.
Additional information
The transition function catches a bad_function_call exception.
The deactivate() method will set `stop_execution_ = true;
https://github.com/ros-planning/navigation2/blob/c213c85c110f5f1d2b689c240ce84fb01eb430f5/nav2_util/include/nav2_util/simple_action_server.hpp#L299-L307
In the work() method, the code will call the completion_callback_ callback, but by default, this callback is nullptr.
https://github.com/ros-planning/navigation2/blob/c213c85c110f5f1d2b689c240ce84fb01eb430f5/nav2_util/include/nav2_util/simple_action_server.hpp#L262-L267