(svn r23111) -Fix: Keep subtype when automatically choosing the cargo for auto-refitting.

src/economy.cpp

@@ -1300,6 +1300,7 @@ static void LoadUnloadVehicle(Vehicle *front, int *cargo_left)
 					if (cargo_left[cid] > amount) {
 						/* Try to find out if auto-refitting would succeed. In case the refit is allowed,
 						 * the returned refit capacity will be greater than zero. */
+						new_subtype = GetBestFittingSubType(v, v, cid);
 						DoCommand(v->tile, v->index, cid | 1U << 6 | new_subtype << 8 | 1U << 16, DC_QUERY_COST, GetCmdRefitVeh(v)); // Auto-refit and only this vehicle including artic parts.
 						if (_returned_refit_capacity > 0) {
 							amount = cargo_left[cid];

src/vehicle_func.h

@@ -21,6 +21,7 @@
 #include "newgrf_config.h"
 #include "track_type.h"
 #include "livery.h"
+#include "cargotype.h"
 
 #define is_custom_sprite(x) (x >= 0xFD)
 #define IS_CUSTOM_FIRSTHEAD_SPRITE(x) (x == 0xFD)
@@ -44,7 +45,7 @@ byte VehicleRandomBits();
 void ResetVehiclePosHash();
 void ResetVehicleColourMap();
 
-byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for);
+byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for, CargoID dest_cargo_type = INVALID_CARGO);
 
 void ViewportAddVehicles(DrawPixelInfo *dpi);
 

src/vehicle_gui.cpp

@@ -213,9 +213,10 @@ static const uint MAX_REFIT_CYCLE = 256;
  * Assuming they are going to carry the same cargo ofcourse!
  * @param v_from the vehicle to match the subtype from
  * @param v_for  the vehicle to get the subtype for
+ * @param dest_cargo_type Destination cargo type, taken from #v_from if set to #INVALID_CARGO.
  * @return the best sub type
  */
-byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for)
+byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for, CargoID dest_cargo_type)
 {
 	const Engine *e_from = v_from->GetEngine();
 	const Engine *e_for  = v_for->GetEngine();
@@ -229,8 +230,10 @@ byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for)
 		return 0;
 	}
 
+	if (dest_cargo_type == INVALID_CARGO) dest_cargo_type = v_from->cargo_type;
+
 	/* It has to be possible for v_for to carry the cargo of v_from. */
-	if (!HasBit(e_for->info.refit_mask, v_from->cargo_type)) return 0;
+	if (!HasBit(e_for->info.refit_mask, dest_cargo_type)) return 0;
 
 	StringID expected_string = GetCargoSubtypeText(v_from);
 
@@ -239,7 +242,7 @@ byte GetBestFittingSubType(Vehicle *v_from, Vehicle *v_for)
 	byte ret_refit_cyc = 0;
 
 	/* Set the 'destination' cargo */
-	v_for->cargo_type = v_from->cargo_type;
+	v_for->cargo_type = dest_cargo_type;
 
 	/* Cycle through the refits */
 	for (uint refit_cyc = 0; refit_cyc < MAX_REFIT_CYCLE; refit_cyc++) {