Departure boards: Fix handling of invalid/empty dispatch schedules

src/departures.cpp

@@ -114,13 +114,18 @@ static bool VehicleSetNextDepartureTime(Ticks *previous_departure, Ticks *waitin
 		if (order->IsScheduledDispatchOrder(true) && !(arrived_at_timing_point && is_current_implicit_order(order))) {
 			const DispatchSchedule &ds = v->orders->GetDispatchScheduleByIndex(order->GetDispatchScheduleIndex());
 
-			StateTicks actual_departure         = -1;
+			StateTicks actual_departure         = INT64_MAX;
 			const StateTicks begin_time         = ds.GetScheduledDispatchStartTick();
 			const uint32_t dispatch_duration    = ds.GetScheduledDispatchDuration();
 			const int32_t max_delay             = ds.GetScheduledDispatchDelay();
 
-			/* Earliest possible departure according to schedue */
-			StateTicks earliest_departure = begin_time + ds.GetScheduledDispatchLastDispatch();
+			/* Earliest possible departure according to the schedule */
+			StateTicks earliest_departure = begin_time;
+			if (ds.GetScheduledDispatchLastDispatch() != INVALID_SCHEDULED_DISPATCH_OFFSET) {
+				earliest_departure += ds.GetScheduledDispatchLastDispatch();
+			} else {
+				earliest_departure--;
+			}
 
 			/* Earliest possible departure according to vehicle current timetable */
 			const StateTicks ready_to_depart_time = state_ticks_base + *previous_departure + order->GetTravelTime() + order->GetTimetabledWait();
@@ -148,11 +153,19 @@ static bool VehicleSetNextDepartureTime(Ticks *previous_departure, Ticks *waitin
 					current_departure += dispatch_duration;
 				}
 
-				if (actual_departure == -1 || actual_departure > current_departure) {
+				if (actual_departure > current_departure) {
 					actual_departure = current_departure;
 				}
 			}
 
+			if (actual_departure == INT64_MAX) {
+				/* Failed to find a dispatch slot for this departure at all, the schedule is invalid/empty.
+				 * Just treat it as a non-dispatch order. */
+				*previous_departure += order->GetTravelTime() + order->GetWaitTime();
+				*waiting_time = 0;
+				return false;
+			}
+
 			*waiting_time = (actual_departure - state_ticks_base).AsTicks() - *previous_departure - order->GetTravelTime();
 			*previous_departure = (actual_departure - state_ticks_base).AsTicks();
 			if (!ds.GetScheduledDispatchReuseSlots()) {

src/departures_gui.cpp

@@ -748,7 +748,6 @@ void DeparturesWindow<Twaypoint>::DrawDeparturesListItems(const Rect &r) const
 	uint arrival = 0;
 
 	StateTicks now_date = _state_ticks;
-	StateTicks max_date = now_date + GetDeparturesMaxTicksAhead();
 
 	/* Draw each departure. */
 	for (uint i = 0; i < max_departures; ++i) {
@@ -774,11 +773,6 @@ void DeparturesWindow<Twaypoint>::DrawDeparturesListItems(const Rect &r) const
 			continue;
 		}
 
-		/* If for some reason the departure is too far in the future or is at a negative time, skip it. */
-		if (d->scheduled_tick > max_date || d->scheduled_tick < 0) {
-			continue;
-		}
-
 		if (d->terminus == INVALID_STATION) continue;
 
 		StringID time_str;