Fix no error message when attaching new template/virtual vehicle fails

See: #187

src/build_vehicle_gui.cpp

@@ -31,6 +31,7 @@
 #include "core/geometry_func.hpp"
 #include "autoreplace_func.h"
 #include "train.h"
+#include "error.h"
 
 #include "widgets/build_vehicle_widget.h"
 
@@ -1676,7 +1677,7 @@ struct BuildVehicleWindow : Window {
 		} else {
 			VehicleID target = (*(this->virtual_train_out))->GetLastUnit()->index;
 
-			DoCommandP(0, (1 << 23) | (1 << 21) | toadd->index, target, CMD_MOVE_RAIL_VEHICLE);
+			DoCommandP(0, (1 << 23) | (1 << 21) | toadd->index, target, CMD_MOVE_RAIL_VEHICLE | CMD_MSG(STR_ERROR_CAN_T_MOVE_VEHICLE), CcMoveNewVirtualEngine);
 		}
 		InvalidateWindowClassesData(WC_CREATE_TEMPLATE);
 		InvalidateWindowClassesData(WC_TEMPLATEGUI_MAIN);
@@ -1691,6 +1692,21 @@ void CcAddVirtualEngine(const CommandCost &result, TileIndex tile, uint32 p1, ui
 	if (window) {
 		Train* train = Train::From(Vehicle::Get(_new_vehicle_id));
 		((BuildVehicleWindow*) window)->AddVirtualEngine(train);
+	} else {
+		DoCommandP(0, _new_vehicle_id | (1 << 21), 0, CMD_SELL_VEHICLE | CMD_MSG(STR_ERROR_CAN_T_SELL_TRAIN));
+	}
+}
+
+void CcMoveNewVirtualEngine(const CommandCost &result, TileIndex tile, uint32 p1, uint32 p2, uint32 cmd)
+{
+	if (result.Failed()) return;
+
+	Window* window = FindWindowById(WC_BUILD_VIRTUAL_TRAIN, 0);
+	if (window) {
+		if (result.IsSuccessWithMessage()) {
+			CommandCost res = result.UnwrapSuccessWithMessage();
+			ShowErrorMessage(STR_ERROR_CAN_T_MOVE_VEHICLE, res.GetErrorMessage(), WL_INFO, 0, 0, res.GetTextRefStackGRF(), res.GetTextRefStackSize(), res.GetTextRefStack(), res.GetExtraErrorMessage());
+		}
 	}
 }
 

src/command_func.h

@@ -135,5 +135,6 @@ CommandCallback CcDeleteVirtualTrain;
 
 /* build_vehicle_gui.cpp */
 CommandCallback CcAddVirtualEngine;
+CommandCallback CcMoveNewVirtualEngine;
 
 #endif /* COMMAND_FUNC_H */

src/command_type.h

@@ -198,6 +198,25 @@ public:
 	 * @return the number of bytes written
 	 */
 	int WriteSummaryMessage(char *buf, char *last, StringID cmd_msg = 0) const;
+
+	bool IsSuccessWithMessage() const
+	{
+		return this->Succeeded() && this->message != INVALID_STRING_ID;
+	}
+
+	void MakeSuccessWithMessage()
+	{
+		assert(this->message != INVALID_STRING_ID);
+		this->success = true;
+	}
+
+	CommandCost UnwrapSuccessWithMessage() const
+	{
+		assert(this->IsSuccessWithMessage());
+		CommandCost res = *this;
+		res.success = false;
+		return res;
+	}
 };
 
 /**

src/network/network_command.cpp

@@ -52,6 +52,7 @@ static CommandCallback * const _callback_table[] = {
 	/* 0x1E */ CcVirtualTrainWagonsMoved,
 	/* 0x1F */ CcDeleteVirtualTrain,
 	/* 0x20 */ CcAddVirtualEngine,
+	/* 0x21 */ CcMoveNewVirtualEngine,
 };
 
 /**

src/train_cmd.cpp

@@ -1396,7 +1396,10 @@ CommandCost CmdMoveRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, u
 
 	auto check_on_failure = [&](CommandCost cost) -> CommandCost {
 		if (delete_failed_virtual && src->IsVirtual()) {
-			return DoCommand(src->tile, src->index | (1 << 21), 0, flags, CMD_SELL_VEHICLE);
+			CommandCost res = DoCommand(src->tile, src->index | (1 << 21), 0, flags, CMD_SELL_VEHICLE);
+			if (res.Failed() || cost.GetErrorMessage() == INVALID_STRING_ID) return res;
+			cost.MakeSuccessWithMessage();
+			return cost;
 		} else {
 			return cost;
 		}