Change: [Linkgraph] Delete links only served by vehicles stopped in depot

A stale link is not deleted if the link refresher finds a vehicle that still serves it.
This commit excludes vehicles stopped in depot for a very long time from the link refresher,
so that their stale links can be deleted.

2 files changed, 8 insertions, 2 deletions

diff --git a/src/linkgraph/linkgraph.h b/src/linkgraph/linkgraph.h
index 3a2c37977..3c5aee872 100644
--- a/src/linkgraph/linkgraph.h
+++ b/src/linkgraph/linkgraph.h
@@ -447,6 +447,9 @@ public:
 	/** Minimum effective distance for timeout calculation. */
 	static const uint MIN_TIMEOUT_DISTANCE = 32;
 
+	/** Number of days before deleting links served only by vehicles stopped in depot. */
+	static const uint STALE_LINK_DEPOT_TIMEOUT = 1024;
+
 	/** Minimum number of days between subsequent compressions of a LG. */
 	static const uint COMPRESSION_INTERVAL = 256;
 
diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index e2c232ac7..fa11c05d5 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -3688,8 +3688,11 @@ void DeleteStaleLinks(Station *from)
 					auto iter = vehicles.begin();
 					while (iter != vehicles.end()) {
 						Vehicle *v = *iter;
-
-						LinkRefresher::Run(v, false); // Don't allow merging. Otherwise lg might get deleted.
+						/* Do not refresh links of vehicles that have been stopped in depot for a long time. */
+						if (!v->IsStoppedInDepot() || static_cast<uint>(_date - v->date_of_last_service) <=
+								LinkGraph::STALE_LINK_DEPOT_TIMEOUT) {
+							LinkRefresher::Run(v, false); // Don't allow merging. Otherwise lg might get deleted.
+						}
 						if (edge.LastUpdate() == _date) {
 							updated = true;
 							break;