From 0a623bc333a54dba04271399b5d73a09498df8b2 Mon Sep 17 00:00:00 2001
From: peter1138 <peter1138@openttd.org>
Date: Sun, 4 Jun 2006 17:49:16 +0000
Subject: [PATCH] (svn r5104) - When refitting a vehicle to its existing cargo
 type, don't lose the cargo onboard (useful when adding wagons to a train)

---
 aircraft_cmd.c | 8 +++++++-
 ship_cmd.c     | 2 +-
 train_cmd.c    | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/aircraft_cmd.c b/aircraft_cmd.c
index dc736e491c..94411d3b26 100644
--- a/aircraft_cmd.c
+++ b/aircraft_cmd.c
@@ -538,7 +538,13 @@ int32 CmdRefitAircraft(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 		u = v->next;
 		mail = (new_cid != CT_PASSENGERS) ? 0 : avi->mail_capacity;
 		u->cargo_cap = mail;
-		v->cargo_count = u->cargo_count = 0;
+		if (v->cargo_type == new_cid) {
+			v->cargo_count = min(pass, v->cargo_count);
+			u->cargo_count = min(mail, u->cargo_count);
+		} else {
+			v->cargo_count = 0;
+			u->cargo_count = 0;
+		}
 		v->cargo_type = new_cid;
 		v->cargo_subtype = new_subtype;
 		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
diff --git a/ship_cmd.c b/ship_cmd.c
index 424d484fbe..b193f954cd 100644
--- a/ship_cmd.c
+++ b/ship_cmd.c
@@ -1061,7 +1061,7 @@ int32 CmdRefitShip(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	}
 
 	if (flags & DC_EXEC) {
-		v->cargo_count = 0;
+		v->cargo_count = (v->cargo_type == new_cid) ? min(v->cargo_cap, v->cargo_count) : 0;
 		v->cargo_type = new_cid;
 		v->cargo_subtype = new_subtype;
 		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
diff --git a/train_cmd.c b/train_cmd.c
index a189a9d9ab..ad0aa8965a 100644
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -1789,7 +1789,7 @@ int32 CmdRefitRailVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 				if (new_cid != v->cargo_type) cost += _price.build_railvehicle >> 8;
 				num += amount;
 				if (flags & DC_EXEC) {
-					v->cargo_count = 0;
+					v->cargo_count = (v->cargo_type == new_cid) ? min(amount, v->cargo_count) : 0;
 					v->cargo_type = new_cid;
 					v->cargo_cap = amount;
 					v->cargo_subtype = new_subtype;