From 69e5da0b544e83ed445cf500938c24602230fa2c Mon Sep 17 00:00:00 2001
From: PeterN <peter1138@openttd.org>
Date: Sat, 8 May 2021 11:36:39 +0100
Subject: [PATCH] Codechange: Don't save unused NewGRF override mappings.
 (#9202)

---
 src/newgrf_commons.h       | 1 +
 src/saveload/newgrf_sl.cpp | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/newgrf_commons.h b/src/newgrf_commons.h
index ed18aaa9e2..b86e3d10af 100644
--- a/src/newgrf_commons.h
+++ b/src/newgrf_commons.h
@@ -218,6 +218,7 @@ public:
 
 	inline uint16 GetMaxMapping() const { return max_new_entities; }
 	inline uint16 GetMaxOffset() const { return max_offset; }
+	inline bool IsValidID(uint16 entity_id) const { return entity_overrides[entity_id] != invalid_ID; }
 };
 
 
diff --git a/src/saveload/newgrf_sl.cpp b/src/saveload/newgrf_sl.cpp
index b2d2b0df99..f7f6ab72e0 100644
--- a/src/saveload/newgrf_sl.cpp
+++ b/src/saveload/newgrf_sl.cpp
@@ -30,6 +30,7 @@ static const SaveLoad _newgrf_mapping_desc[] = {
 void Save_NewGRFMapping(const OverrideManagerBase &mapping)
 {
 	for (uint i = 0; i < mapping.GetMaxMapping(); i++) {
+		if (!mapping.IsValidID(i)) continue;
 		SlSetArrayIndex(i);
 		SlObject(&mapping.mapping_ID[i], _newgrf_mapping_desc);
 	}