From 89ddc87c16b511109c85c219998929673e6f9bbf Mon Sep 17 00:00:00 2001
From: Cyprian Klimaszewski <kapitan.cypek@gmail.com>
Date: Tue, 27 Jan 2026 21:41:45 +0100
Subject: [PATCH] Codefix 97f3e5b: Restore defensive programming for
 _tile_type_procs. (#15165)

---
 src/landscape.cpp | 8 +++++++-
 src/tile_cmd.h    | 2 +-
 src/tile_map.h    | 4 ++--
 src/tile_type.h   | 4 ++++
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/landscape.cpp b/src/landscape.cpp
index c09f7d8135..423616a457 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -66,7 +66,7 @@ extern const TileTypeProcs
  * @ingroup TileCallbackGroup
  * @see TileType
  */
-const EnumClassIndexContainer<std::array<const TileTypeProcs *, to_underlying(TileType::End)>, TileType> _tile_type_procs = {
+const EnumClassIndexContainer<std::array<const TileTypeProcs *, to_underlying(TileType::MaxSize)>, TileType> _tile_type_procs = {
 	&_tile_type_clear_procs, // Callback functions for TileType::Clear tiles
 	&_tile_type_rail_procs, // Callback functions for TileType::Railway tiles
 	&_tile_type_road_procs, // Callback functions for TileType::Road tiles
@@ -78,6 +78,12 @@ const EnumClassIndexContainer<std::array<const TileTypeProcs *, to_underlying(Ti
 	&_tile_type_industry_procs, // Callback functions for TileType::Industry tiles
 	&_tile_type_tunnelbridge_procs, // Callback functions for TileType::TunnelBridge tiles
 	&_tile_type_object_procs, // Callback functions for TileType::Object tiles
+	/* Explicitly initialize invalid elements to make sure that they are nullptr. */
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
 };
 
 /** landscape slope => sprite */
diff --git a/src/tile_cmd.h b/src/tile_cmd.h
index 89dba0271e..1fb89d88cf 100644
--- a/src/tile_cmd.h
+++ b/src/tile_cmd.h
@@ -169,7 +169,7 @@ struct TileTypeProcs {
 	CheckBuildAboveProc *check_build_above_proc;
 };
 
-extern const EnumClassIndexContainer<std::array<const TileTypeProcs *, to_underlying(TileType::End)>, TileType> _tile_type_procs;
+extern const EnumClassIndexContainer<std::array<const TileTypeProcs *, to_underlying(TileType::MaxSize)>, TileType> _tile_type_procs;
 
 TrackStatus GetTileTrackStatus(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side = INVALID_DIAGDIR);
 VehicleEnterTileStates VehicleEnterTile(Vehicle *v, TileIndex tile, int x, int y);
diff --git a/src/tile_map.h b/src/tile_map.h
index 5860c6b55b..0934231906 100644
--- a/src/tile_map.h
+++ b/src/tile_map.h
@@ -96,7 +96,7 @@ inline uint TilePixelHeightOutsideMap(int x, int y)
 [[debug_inline]] inline static TileType GetTileType(Tile tile)
 {
 	assert(tile < Map::Size());
-	return TileType(GB(tile.type(), 4, 4));
+	return TileType(GB(tile.type(), 4, TILE_TYPE_BITS));
 }
 
 /**
@@ -135,7 +135,7 @@ inline void SetTileType(Tile tile, TileType type)
 	 * edges of the map. If _settings_game.construction.freeform_edges is true,
 	 * the upper edges of the map are also VOID tiles. */
 	assert(IsInnerTile(tile) == (type != TileType::Void));
-	SB(tile.type(), 4, 4, to_underlying(type));
+	SB(tile.type(), 4, TILE_TYPE_BITS, to_underlying(type));
 }
 
 /**
diff --git a/src/tile_type.h b/src/tile_type.h
index 75af407c13..290a441b50 100644
--- a/src/tile_type.h
+++ b/src/tile_type.h
@@ -36,6 +36,7 @@ static constexpr uint MAX_SNOWLINE_HEIGHT = (MAX_TILE_HEIGHT - 2); ///< Maximum
 static constexpr uint DEF_SNOW_COVERAGE = 40;                      ///< Default snow coverage.
 static constexpr uint DEF_DESERT_COVERAGE = 50;                    ///< Default desert coverage.
 
+static constexpr size_t TILE_TYPE_BITS = 4; ///< How many bits in map array are dedicated for type of each tile.
 
 /**
  * The different types of tiles.
@@ -57,8 +58,11 @@ enum class TileType : uint8_t {
 	TunnelBridge, ///< Tunnel entry/exit and bridge heads.
 	Object, ///< Contains objects such as transmitters and owned land.
 	End, ///< End marker.
+	MaxSize = 1U << TILE_TYPE_BITS, ///< The maximum possible number of tile types to be stored in map.
 };
 
+static_assert(TileType::End <= TileType::MaxSize);
+
 /**
  * Additional infos of a tile on a tropic game.
  *