Fix #10511: Delay 'go to nearest depot' orders

Delay the nearest depot order search for a day if the destination has been set to zero, which happens when it has already attempted to do so and failed to find a valid destination.

src/order_cmd.cpp

@@ -1961,34 +1961,37 @@ bool UpdateOrderDest(Vehicle *v, const Order *order, int conditional_depth, bool
 			}
 
 			if (v->current_order.GetDepotActionType() & ODATFB_NEAREST_DEPOT) {
-				/* We need to search for the nearest depot (hangar). */
-				ClosestDepot closestDepot = v->FindClosestDepot();
-
-				if (closestDepot.found) {
-					/* PBS reservations cannot reverse */
-					if (pbs_look_ahead && closestDepot.reverse) return false;
-
-					v->SetDestTile(closestDepot.location);
-					v->current_order.SetDestination(closestDepot.destination);
-
-					/* If there is no depot in front, reverse automatically (trains only) */
-					if (v->type == VEH_TRAIN && closestDepot.reverse) Command<CMD_REVERSE_TRAIN_DIRECTION>::Do(DC_EXEC, v->index, false);
-
-					if (v->type == VEH_AIRCRAFT) {
-						Aircraft *a = Aircraft::From(v);
-						if (a->state == FLYING && a->targetairport != closestDepot.destination) {
-							/* The aircraft is now heading for a different hangar than the next in the orders */
-							AircraftNextAirportPos_and_Order(a);
+				/* Try to delay the search for a bit if the previous destination is invalid. */
+				if (v->dest_tile != 0 || TimerGameTick::counter % Ticks::DAY_TICKS == 0) {
+					/* We need to search for the nearest depot (hangar). */
+					ClosestDepot closestDepot = v->FindClosestDepot();
+
+					if (closestDepot.found) {
+						/* PBS reservations cannot reverse */
+						if (pbs_look_ahead && closestDepot.reverse) return false;
+
+						v->SetDestTile(closestDepot.location);
+						v->current_order.SetDestination(closestDepot.destination);
+
+						/* If there is no depot in front, reverse automatically (trains only) */
+						if (v->type == VEH_TRAIN && closestDepot.reverse) Command<CMD_REVERSE_TRAIN_DIRECTION>::Do(DC_EXEC, v->index, false);
+
+						if (v->type == VEH_AIRCRAFT) {
+							Aircraft *a = Aircraft::From(v);
+							if (a->state == FLYING && a->targetairport != closestDepot.destination) {
+								/* The aircraft is now heading for a different hangar than the next in the orders */
+								AircraftNextAirportPos_and_Order(a);
+							}
 						}
+						return true;
 					}
-					return true;
-				}
 
-				/* If there is no depot, we cannot help PBS either. */
-				if (pbs_look_ahead) return false;
+					/* If there is no depot, we cannot help PBS either. */
+					if (pbs_look_ahead) return false;
 
-				UpdateVehicleTimetable(v, true);
-				v->IncrementRealOrderIndex();
+					UpdateVehicleTimetable(v, true);
+					v->IncrementRealOrderIndex();
+				}
 			} else {
 				if (v->type != VEH_AIRCRAFT) {
 					v->SetDestTile(Depot::Get(order->GetDestination())->xy);