Only show ship is lost messages if lost for a significant time

src/saveload/extended_ver_sl.cpp

@@ -127,6 +127,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_DOCKING_CACHE_VER,      XSCF_IGNORABLE_ALL,       1,   1, "docking_cache_ver",         nullptr, nullptr, nullptr        },
 	{ XSLFI_EXTRA_CHEATS,           XSCF_NULL,                1,   1, "extra_cheats",              nullptr, nullptr, "CHTX"         },
 	{ XSLFI_TOWN_MULTI_BUILDING,    XSCF_NULL,                1,   1, "town_multi_building",       nullptr, nullptr, nullptr        },
+	{ XSLFI_SHIP_LOST_COUNTER,      XSCF_NULL,                1,   1, "ship_lost_counter",         nullptr, nullptr, nullptr        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, nullptr, nullptr, nullptr, nullptr },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -84,6 +84,7 @@ enum SlXvFeatureIndex {
 	XSLFI_DOCKING_CACHE_VER,                      ///< Multiple docks - docking tile cache version
 	XSLFI_EXTRA_CHEATS,                           ///< Extra cheats
 	XSLFI_TOWN_MULTI_BUILDING,                    ///< Allow multiple stadium/church buildings in a single town
+	XSLFI_SHIP_LOST_COUNTER,                      ///< Ship lost counter
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk

src/saveload/vehicle_sl.cpp

@@ -840,6 +840,7 @@ const SaveLoad *GetVehicleDescription(VehicleType vt)
 		      SLE_VAR(Ship, state,                     SLE_UINT8),
 		SLE_CONDDEQUE(Ship, path,                      SLE_UINT8,                  SLV_SHIP_PATH_CACHE, SL_MAX_VERSION),
 		  SLE_CONDVAR(Ship, rotation,                  SLE_UINT8,                  SLV_SHIP_ROTATION, SL_MAX_VERSION),
+		SLE_CONDVAR_X(Ship, lost_count,                SLE_UINT8,                     SL_MIN_VERSION, SL_MAX_VERSION, SlXvFeatureTest(XSLFTO_AND, XSLFI_SHIP_LOST_COUNTER)),
 
 		SLE_CONDNULL(16, SLV_2, SLV_144), // old reserved space
 

src/ship.h

@@ -31,6 +31,7 @@ struct Ship FINAL : public SpecializedVehicle<Ship, VEH_SHIP> {
 	Direction rotation;   ///< Visible direction.
 	int16 rotation_x_pos; ///< NOSAVE: X Position before rotation.
 	int16 rotation_y_pos; ///< NOSAVE: Y Position before rotation.
+	uint8 lost_count;     ///< Count of number of failed pathfinder attempts
 
 	/** We don't want GCC to zero our struct! It already is zeroed and has an index! */
 	Ship() : SpecializedVehicleBase() {}

src/table/newgrf_debug_data.h

@@ -12,6 +12,7 @@
 #include "../newgrf_roadtype.h"
 #include "../date_func.h"
 #include "../timetable.h"
+#include "../ship.h"
 
 /* Helper for filling property tables */
 #define NIP(prop, base, variable, type, name) { name, (ptrdiff_t)cpp_offsetof(base, variable), cpp_sizeof(base, variable), prop, type }
@@ -149,6 +150,12 @@ class NIHVehicle : public NIHelper {
 					t->wait_counter, t->reverse_distance, t->tunnel_bridge_signal_num, t->speed_restriction);
 			print(buffer);
 		}
+		if (v->type == VEH_SHIP) {
+			const Ship *s = Ship::From(v);
+			seprintf(buffer, lastof(buffer), "  Lost counter: %u",
+					s->lost_count);
+			print(buffer);
+		}
 
 		if (HasBit(v->vehicle_flags, VF_SEPARATION_ACTIVE)) {
 			std::vector<TimetableProgress> progress_array = PopulateSeparationState(v);

src/vehicle.cpp

@@ -885,16 +885,27 @@ void Vehicle::HandlePathfindingResult(bool path_found)
 
 		/* Clear the flag as the PF's problem was solved. */
 		ClrBit(this->vehicle_flags, VF_PATHFINDER_LOST);
+		if (this->type == VEH_SHIP) {
+			Ship::From(this)->lost_count = 0;
+		}
 		/* Delete the news item. */
 		DeleteVehicleNews(this->index, STR_NEWS_VEHICLE_IS_LOST);
 		return;
 	}
 
-	/* Were we already lost? */
-	if (HasBit(this->vehicle_flags, VF_PATHFINDER_LOST)) return;
+	if (this->type == VEH_SHIP) {
+		SetBit(this->vehicle_flags, VF_PATHFINDER_LOST);
+		if (Ship::From(this)->lost_count == 255) return;
+		Ship::From(this)->lost_count++;
+		if (Ship::From(this)->lost_count != 16) return;
+	} else {
+		/* Were we already lost? */
+		if (HasBit(this->vehicle_flags, VF_PATHFINDER_LOST)) return;
+
+		/* It is first time the problem occurred, set the "lost" flag. */
+		SetBit(this->vehicle_flags, VF_PATHFINDER_LOST);
+	}
 
-	/* It is first time the problem occurred, set the "lost" flag. */
-	SetBit(this->vehicle_flags, VF_PATHFINDER_LOST);
 	/* Notify user about the event. */
 	AI::NewEvent(this->owner, new ScriptEventVehicleLost(this->index));
 	if (_settings_client.gui.lost_vehicle_warn && this->owner == _local_company) {