Error calling cancel_goal() in simple state DONE

[martiniil]

Using a SimpleActionClient, I would like to be able to cancel a goal with minimal delay. But using cancel_goal() sometimes yields the following error:

Received comm state PREEMPTING when in simple state DONE with SimpleActionClient in NS /sequence_move_group

This is due to the action client transitioning from DONE -> WAITING_FOR_CANCEL_ACK. In my opinion this should not happen. (which would be in accordance with the figure of the state transitions: http://wiki.ros.org/actionlib/DetailedDescription).

[jschleicher]

Probably one would want a similar check as in cpp 3db5a80 for the python client. The python client lacks such a "ignore cancel request" section

actionlib/src/actionlib/action_client.py

Line 139 in 7c18334

def cancel(self):