From 0da467c37425b98dc96c3507fec90073d49e9241 Mon Sep 17 00:00:00 2001
From: Lars <larsh@apache.org>
Date: Fri, 30 May 2025 17:20:34 -0700
Subject: [PATCH] address review

---
 src/mapblock.cpp               |  2 +-
 src/mapblock.h                 |  4 ++--
 src/unittest/test_mapblock.cpp | 29 ++++++++++++++++++++++++++++-
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/mapblock.cpp b/src/mapblock.cpp
index fd16b6397..5f3c5c850 100644
--- a/src/mapblock.cpp
+++ b/src/mapblock.cpp
@@ -429,7 +429,7 @@ void MapBlock::serialize(std::ostream &os_compressed, u8 version, bool disk, int
 	const u8 params_width = 2;
 	if(disk)
 	{
-		const int size = m_is_mono_block ? 1 : nodecount;
+		const size_t size = m_is_mono_block ? 1 : nodecount;
 		MapNode *tmp_nodes = new MapNode[size];
 		memcpy(tmp_nodes, data, size * sizeof(MapNode));
 		getBlockNodeIdMapping(&nimap, tmp_nodes, m_gamedef->ndef(), size);
diff --git a/src/mapblock.h b/src/mapblock.h
index c5b156b50..8effc6ce9 100644
--- a/src/mapblock.h
+++ b/src/mapblock.h
@@ -21,9 +21,7 @@ class NodeMetadataList;
 class IGameDef;
 class MapBlockMesh;
 class VoxelManipulator;
-#if BUILD_UNITTESTS
 class TestMapBlock;
-#endif
 
 #define BLOCK_TIMESTAMP_UNDEFINED 0xffffffff
 
@@ -442,7 +440,9 @@ private:
 	*/
 
 	void deSerialize_pre22(std::istream &is, u8 version, bool disk);
+	// check if all nodes are identical, if so store them as a single node
 	void tryConvertToMonoblock();
+	// if only a single node is stored, expand storage back to the full array
 	void deconvertMonoblock();
 	void reallocate(u32 c, MapNode n);
 
diff --git a/src/unittest/test_mapblock.cpp b/src/unittest/test_mapblock.cpp
index d94497335..4ca66c19c 100644
--- a/src/unittest/test_mapblock.cpp
+++ b/src/unittest/test_mapblock.cpp
@@ -121,7 +121,6 @@ void TestMapBlock::testMonoblock(IGameDef *gamedef)
 	UASSERT(vmm.getNode({5,5,5}).param0 == 42);
 
 	block.setNode(5,5,5,MapNode(23));
-	t = block.data;
 
 	block.copyFrom(vmm);
 	UASSERT(block.m_is_mono_block);
@@ -130,6 +129,34 @@ void TestMapBlock::testMonoblock(IGameDef *gamedef)
 	vmm.setNode({5,5,5}, MapNode(23));
 	block.copyFrom(vmm);
 	UASSERT(!block.m_is_mono_block);
+
+	vmm.setNode({5,5,5}, MapNode(42,1,0));
+	block.copyFrom(vmm);
+	UASSERT(!block.m_is_mono_block);
+
+	vmm.setNode({5,5,5}, MapNode(42,0,1));
+	block.copyFrom(vmm);
+	UASSERT(!block.m_is_mono_block);
+
+	vmm.setNode({5,5,5}, MapNode(42));
+	block.copyFrom(vmm);
+	UASSERT(block.m_is_mono_block);
+
+	block.setNode(5,5,5,MapNode(23));
+	block.tryConvertToMonoblock();
+	UASSERT(!block.m_is_mono_block);
+
+	block.setNode(5,5,5,MapNode(42, 1, 0));
+	block.tryConvertToMonoblock();
+	UASSERT(!block.m_is_mono_block);
+
+	block.setNode(5,5,5,MapNode(42, 0, 1));
+	block.tryConvertToMonoblock();
+	UASSERT(!block.m_is_mono_block);
+
+	block.setNode(5,5,5,MapNode(42));
+	block.tryConvertToMonoblock();
+	UASSERT(block.m_is_mono_block);
 }
 
 void TestMapBlock::testSaveLoad(IGameDef *gamedef, const u8 version)