Fix #12301: Update ship current order destination tile when relocatin…

…g buoys

Moving buoys caused current_order to be detected as unchanged, making pathfinders to compute a path to an outdated v->dest_tile.

Properly update v->dest_tile before reaching pathfinders.

src/order_cmd.cpp

@@ -2197,9 +2197,23 @@ bool ProcessOrders(Vehicle *v)
 	}
 
 	/* If it is unchanged, keep it. */
-	if (order->Equals(v->current_order) && (v->type == VEH_AIRCRAFT || v->dest_tile != 0) &&
-			(v->type != VEH_SHIP || !order->IsType(OT_GOTO_STATION) || Station::Get(order->GetDestination())->ship_station.tile != INVALID_TILE)) {
-		return false;
+	if (order->Equals(v->current_order) && (v->type == VEH_AIRCRAFT || v->dest_tile != 0)) {
+		if (v->type != VEH_SHIP) {
+			return false;
+		} else {
+			switch (order->GetType()) {
+				case OT_GOTO_STATION:
+					if (Station::Get(order->GetDestination())->ship_station.tile != INVALID_TILE) return false;
+					break;
+
+				case OT_GOTO_WAYPOINT:
+					if (Waypoint::Get(order->GetDestination())->xy == v->dest_tile) return false;
+					break;
+
+				default:
+					return false;
+			}
+		}
 	}
 
 	/* Otherwise set it, and determine the destination tile. */

src/waypoint_cmd.cpp

@@ -22,6 +22,7 @@
 #include "window_func.h"
 #include "timer/timer_game_calendar.h"
 #include "vehicle_func.h"
+#include "ship.h"
 #include "string_func.h"
 #include "company_func.h"
 #include "newgrf_station.h"
@@ -327,8 +328,14 @@ CommandCost CmdBuildBuoy(DoCommandFlag flags, TileIndex tile)
 		if (wp == nullptr) {
 			wp = new Waypoint(tile);
 		} else {
-			/* Move existing (recently deleted) buoy to the new location */
-			wp->xy = tile;
+			if (wp->xy != tile) {
+				/* Move existing (recently deleted) buoy to the new location. */
+				wp->xy = tile;
+				for (Ship *v : Ship::Iterate()) {
+					if (!v->current_order.IsType(OT_GOTO_WAYPOINT) || v->current_order.GetDestination() != wp->index) continue;
+					v->SetDestTile(wp->xy);
+				}
+			}
 			InvalidateWindowData(WC_WAYPOINT_VIEW, wp->index);
 		}
 		wp->rect.BeforeAddTile(tile, StationRect::ADD_TRY);