(svn r25320) -Fix [FS#5577]: link graph start time was not accounted for when cheating dates

src/cheat_gui.cpp

@@ -24,6 +24,7 @@
 #include "rail_gui.h"
 #include "settings_gui.h"
 #include "company_gui.h"
+#include "linkgraph/linkgraph.h"
 
 #include "widgets/cheat_widget.h"
 
@@ -100,7 +101,10 @@ static int32 ClickChangeDateCheat(int32 p1, int32 p2)
 	p1 = Clamp(p1, MIN_YEAR, MAX_YEAR);
 	if (p1 == _cur_year) return _cur_year;
 
-	SetDate(ConvertYMDToDate(p1, ymd.month, ymd.day), _date_fract);
+	Date new_date = ConvertYMDToDate(p1, ymd.month, ymd.day);
+	LinkGraph *lg;
+	FOR_ALL_LINK_GRAPHS(lg) lg->ShiftDates(new_date - _date);
+	SetDate(new_date, _date_fract);
 	EnginesMonthlyLoop();
 	SetWindowDirty(WC_STATUS_BAR, 0);
 	InvalidateWindowClassesData(WC_BUILD_STATION, 0);

src/date.cpp

@@ -18,6 +18,7 @@
 #include "date_func.h"
 #include "vehicle_base.h"
 #include "rail_gui.h"
+#include "linkgraph/linkgraph.h"
 #include "saveload/saveload.h"
 
 Year      _cur_year;   ///< Current year, starting at 0
@@ -211,6 +212,9 @@ static void OnNewYear()
 		_date -= days_this_year;
 		FOR_ALL_VEHICLES(v) v->date_of_last_service -= days_this_year;
 
+		LinkGraph *lg;
+		FOR_ALL_LINK_GRAPHS(lg) lg->ShiftDates(-days_this_year);
+
 #ifdef ENABLE_NETWORK
 		/* Because the _date wraps here, and text-messages expire by game-days, we have to clean out
 		 *  all of them if the date is set back, else those messages will hang for ever */

src/linkgraph/linkgraph.cpp

@@ -43,6 +43,24 @@ inline void LinkGraph::BaseEdge::Init(uint distance)
 	this->next_edge = INVALID_NODE;
 }
 
+/**
+ * Shift all dates by given interval.
+ * This is useful if the date has been modified with the cheat menu.
+ * @param interval Number of days to be added or subtracted.
+ */
+void LinkGraph::ShiftDates(int interval)
+{
+	this->last_compression += interval;
+	for (NodeID node1 = 0; node1 < this->Size(); ++node1) {
+		BaseNode &source = this->nodes[node1];
+		if (source.last_update != INVALID_DATE) source.last_update += interval;
+		for (NodeID node2 = 0; node2 < this->Size(); ++node2) {
+			BaseEdge &edge = this->edges[node1][node2];
+			if (edge.last_update != INVALID_DATE) edge.last_update += interval;
+		}
+	}
+}
+
 void LinkGraph::Compress()
 {
 	this->last_compression = (_date + this->last_compression) / 2;

src/linkgraph/linkgraph.h

@@ -442,6 +442,7 @@ public:
 	LinkGraph(CargoID cargo) : cargo(cargo), last_compression(_date) {}
 
 	void Init(uint size);
+	void ShiftDates(int interval);
 	void Compress();
 	void Merge(LinkGraph *other);