navd: fix hysteresis when reaching destination

[sshane]

Noticed this when reading the code to start refactoring. Basically, the desired behavior (from the comments) is that you reach your destination, stop, but nothing is cleared until you start driving away:

openpilot/selfdrive/navd/navd.py

Lines 271 to 277 in 5cfb79e

	cloudlog.warning("Destination reached")
	Params().remove("NavDestination")
	# Clear route if driving away from destination
	dist = self.nav_destination.distance_to(self.last_position)
	if dist > REROUTE_DISTANCE:
	self.clear_route()

However since we clear the parameter first, we clear the route anyway on the next loop:

openpilot/selfdrive/navd/navd.py

Lines 102 to 105 in 5cfb79e

	new_destination = coordinate_from_param("NavDestination", self.params)
	if new_destination is None:
	self.clear_route()
	return

We can avoid clearing the param until we clear the route and don't need to worry about re-routing due to this check here:

openpilot/selfdrive/navd/navd.py

Lines 300 to 302 in 5cfb79e

	# Don't recompute in last segment, assume destination is reached
	if self.step_idx == len(self.route) - 1:
	return False

[sshane]

However this is odd behavior to show all zeros for the ETA, maybe we should remove this broken code altogether. @adeebshihadeh have any preference? actually we handle this! we can merge this then. I'll post a comparison

[sshane]

This is the fixed behavior, before this, it would briefly show that you've arrived, then disappear. Includes fixed nav banner instructions from #29034 in the video

you.have.arrived.fixed.2.mp4

[adeebshihadeh]

Remove the distance in the top banner too?

[adeebshihadeh]

move this to clear route instead?

[sshane]

Can't, it's used to temporarily hide the route on errors as well. It's intentional there's still a NavDestination but no route

[sshane]

nav.arrived.and.left.mp4