Fix: Vehicle list windows did not update when this year's profit changed

Remove caching from vehicle group object. and recalculate it whenever
required instead.

(cherry picked from commit 6b8f9b50b9)

# Conflicts:
#	src/vehicle_gui.cpp

src/vehicle_gui.cpp

@@ -235,7 +235,7 @@ void BaseVehicleListWindow::BuildVehicleList()
 	if (this->grouping == GB_NONE) {
 		uint max_unitnumber = 0;
 		for (auto it = this->vehicles.begin(); it != this->vehicles.end(); ++it) {
-			this->vehgroups.emplace_back(it, it + 1, (*it)->GetDisplayProfitThisYear(), (*it)->GetDisplayProfitLastYear(), (*it)->age);
+			this->vehgroups.emplace_back(it, it + 1);
 
 			max_unitnumber = std::max<uint>(max_unitnumber, (*it)->unitnumber);
 		}
@@ -254,17 +254,7 @@ void BaseVehicleListWindow::BuildVehicleList()
 				return v->FirstShared() == first_shared;
 			});
 
-			Money display_profit_this_year = 0;
-			Money display_profit_last_year = 0;
-			Date age = 0;
-			for (auto it = begin; it != end; ++it) {
-				const Vehicle * const v = (*it);
-				display_profit_this_year += v->GetDisplayProfitThisYear();
-				display_profit_last_year += v->GetDisplayProfitLastYear();
-				age = std::max<Date>(age, v->age);
-			}
-
-			this->vehgroups.emplace_back(begin, end, display_profit_this_year, display_profit_last_year, age);
+			this->vehgroups.emplace_back(begin, end);
 
 			max_num_vehicles = std::max<uint>(max_num_vehicles, static_cast<uint>(end - begin));
 
@@ -1459,25 +1449,25 @@ static bool VehicleGroupLengthSorter(const GUIVehicleGroup &a, const GUIVehicleG
 /** Sort vehicle groups by the total profit this year */
 static bool VehicleGroupTotalProfitThisYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
 {
-	return a.display_profit_this_year < b.display_profit_this_year;
+	return a.GetDisplayProfitThisYear() < b.GetDisplayProfitThisYear();
 }
 
 /** Sort vehicle groups by the total profit last year */
 static bool VehicleGroupTotalProfitLastYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
 {
-	return a.display_profit_last_year < b.display_profit_last_year;
+	return a.GetDisplayProfitLastYear() < b.GetDisplayProfitLastYear();
 }
 
 /** Sort vehicle groups by the average profit this year */
 static bool VehicleGroupAverageProfitThisYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
 {
-	return a.display_profit_this_year * static_cast<uint>(b.NumVehicles()) < b.display_profit_this_year * static_cast<uint>(a.NumVehicles());
+	return a.GetDisplayProfitThisYear() * static_cast<uint>(b.NumVehicles()) < b.GetDisplayProfitThisYear() * static_cast<uint>(a.NumVehicles());
 }
 
 /** Sort vehicle groups by the average profit last year */
 static bool VehicleGroupAverageProfitLastYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
 {
-	return a.display_profit_last_year * static_cast<uint>(b.NumVehicles()) < b.display_profit_last_year * static_cast<uint>(a.NumVehicles());
+	return a.GetDisplayProfitLastYear() * static_cast<uint>(b.NumVehicles()) < b.GetDisplayProfitLastYear() * static_cast<uint>(a.NumVehicles());
 }
 
 /** Sort vehicles by their number */
@@ -1946,12 +1936,12 @@ void BaseVehicleListWindow::DrawVehicleListItems(VehicleID selected_vehicle, int
 				GfxFillRect((text_right - 1) - (FONT_HEIGHT_SMALL - 2), y + 1, text_right - 1, (y + 1) + (FONT_HEIGHT_SMALL - 2), ccolour, FILLRECT_OPAQUE);
 			}
 		} else {
-			SetDParam(0, vehgroup.display_profit_this_year);
-			SetDParam(1, vehgroup.display_profit_last_year);
+			SetDParam(0, vehgroup.GetDisplayProfitThisYear());
+			SetDParam(1, vehgroup.GetDisplayProfitLastYear());
 			DrawString(text_left, text_right, y + line_height - FONT_HEIGHT_SMALL - WD_FRAMERECT_BOTTOM - 1, STR_VEHICLE_LIST_PROFIT_THIS_YEAR_LAST_YEAR);
 		}
 
-		DrawVehicleProfitButton(vehgroup.age, vehgroup.display_profit_last_year, vehgroup.NumVehicles(), vehicle_button_x, y + FONT_HEIGHT_NORMAL + 3);
+		DrawVehicleProfitButton(vehgroup.GetOldestVehicleAge(), vehgroup.GetDisplayProfitLastYear(), vehgroup.NumVehicles(), vehicle_button_x, y + FONT_HEIGHT_NORMAL + 3);
 
 		switch (this->grouping) {
 			case GB_NONE: {

src/vehicle_gui_base.h

@@ -14,32 +14,54 @@
 #include "date_type.h"
 #include "economy_type.h"
 #include "sortlist_type.h"
+#include "vehicle_base.h"
 #include "vehiclelist.h"
 #include "window_gui.h"
 #include "widgets/dropdown_type.h"
 #include "cargo_type.h"
 #include <iterator>
+#include <numeric>
 
 typedef GUIList<const Vehicle*, CargoID> GUIVehicleList;
 
 struct GUIVehicleGroup {
 	VehicleList::const_iterator vehicles_begin;    ///< Pointer to beginning element of this vehicle group.
 	VehicleList::const_iterator vehicles_end;      ///< Pointer to past-the-end element of this vehicle group.
-	Money display_profit_this_year;                ///< Total profit for the vehicle group this year.
-	Money display_profit_last_year;                ///< Total profit for the vehicle group laste year.
-	Date age;                                      ///< Age in days of oldest vehicle in the group.
 
-	GUIVehicleGroup(VehicleList::const_iterator vehicles_begin, VehicleList::const_iterator vehicles_end, Money display_profit_this_year, Money display_profit_last_year, Date age)
-		: vehicles_begin(vehicles_begin), vehicles_end(vehicles_end), display_profit_this_year(display_profit_this_year), display_profit_last_year(display_profit_last_year), age(age) {}
+	GUIVehicleGroup(VehicleList::const_iterator vehicles_begin, VehicleList::const_iterator vehicles_end)
+		: vehicles_begin(vehicles_begin), vehicles_end(vehicles_end) {}
 
 	std::ptrdiff_t NumVehicles() const
 	{
-		return std::distance(vehicles_begin, vehicles_end);
+		return std::distance(this->vehicles_begin, this->vehicles_end);
 	}
+
 	const Vehicle *GetSingleVehicle() const
 	{
-		assert(NumVehicles() == 1);
-		return vehicles_begin[0];
+		assert(this->NumVehicles() == 1);
+		return this->vehicles_begin[0];
+	}
+
+	Money GetDisplayProfitThisYear() const
+	{
+		return std::accumulate(this->vehicles_begin, this->vehicles_end, (Money)0, [](Money acc, const Vehicle *v) {
+			return acc + v->GetDisplayProfitThisYear();
+		});
+	}
+
+	Money GetDisplayProfitLastYear() const
+	{
+		return std::accumulate(this->vehicles_begin, this->vehicles_end, (Money)0, [](Money acc, const Vehicle *v) {
+			return acc + v->GetDisplayProfitLastYear();
+		});
+	}
+
+	Date GetOldestVehicleAge() const
+	{
+		const Vehicle *oldest = *std::max_element(this->vehicles_begin, this->vehicles_end, [](const Vehicle *v_a, const Vehicle *v_b) {
+			return v_a->age < v_b->age;
+		});
+		return oldest->age;
 	}
 };