(svn r1743) -Fix: Multistop: Added some debug output and made sure that orphaned slots are cleared.

roadveh_cmd.c

@@ -1470,8 +1470,8 @@ again:
 			//we have arrived at the wrong station
 			//XXX The question is .. what to do? Actually we shouldn't be here
 			//but I guess we need to clear the slot
-			DEBUG(misc, 2) ("Multistop: Wrong station, force a slot clearing");
-			ClearSlot(v, rs);
+ 			DEBUG(misc, 1) ("Multistop: Wrong station, force a slot clearing. Vehicle %d at 0x%x, should go to 0x%x of station %d (%x), destination 0x%x", v->unitnumber, v->tile, v->u.road.slot->xy, st->index, st->xy, v->dest_tile);
+			ClearSlot(v, v->u.road.slot);
 		}
 
 		StartRoadVehSound(v);

station_cmd.c

@@ -2398,6 +2398,43 @@ static void StationHandleBigTick(Station *st)
 		if (++st->delete_ctr >= 8)
 			DeleteStation(st);
 	}
+
+	//Here we saveguard against orphaned slots
+	{
+		RoadStop *rs;
+
+		for (rs = GetPrimaryRoadStop(st, RS_BUS); rs != NULL; rs = rs->next) {
+			int k;
+			for (k = 0; k < NUM_SLOTS; k++) {
+				if (rs->slot[k] != INVALID_SLOT) {
+					Vehicle *v = GetVehicle(rs->slot[k]);
+
+					if (v->u.road.slot != rs) {
+						DEBUG(misc, 1) ("Bus Slot Desync! cleaning up (Don't panic)");
+						v->u.road.slot = NULL;
+						v->u.road.slot_age = 0;
+						rs->slot[k] = INVALID_SLOT;
+					}
+				}
+			}
+		}
+
+		for (rs = GetPrimaryRoadStop(st, RS_TRUCK); rs != NULL; rs = rs->next) {
+			int k;
+			for (k = 0; k < NUM_SLOTS; k++) {
+				if (rs->slot[k] != INVALID_SLOT) {
+					Vehicle *v = GetVehicle(rs->slot[k]);
+
+					if (v->u.road.slot != rs) {
+						DEBUG(misc, 1) ("Truck Slot Desync! cleaning up (Don't panic)");
+						v->u.road.slot = NULL;
+						v->u.road.slot_age = 0;
+						rs->slot[k] = INVALID_SLOT;
+					}
+				}
+			}
+		}
+	}
 }
 
 static inline void byte_inc_sat(byte *p) { byte b = *p + 1; if (b != 0) *p = b; }