Hi!

I am struggling with the understanding of the navigate with replanning and recovery behavior tree of Nav2.

Specially I don't really understand why it is being used a sequence star in the reactive fallback of the right of the BT. I have understood that the SequenceStar stores the last node that returned a Failure to start from it when ticking again its children. However, if one of the children of the SequenceStar fails, the SequenceStar and the ReactiveFallback fail too. If the ReactiveFallback fails, the RecoveryNode won't tick its first child again and so everything fails and ends. So what is the reason for storing the last node that returned failure in the SequenceStar?

Moreover, does the ClearEntireCostmap erase the costmap and then loads it again from scratch? (Both eith the clear local and global costmap)

Thank you for your help!