From a4293f6f1a67b2c3f98ace2367257eb69725a841 Mon Sep 17 00:00:00 2001
From: Flonja <20887403+Flonja@users.noreply.github.com>
Date: Mon, 7 Jul 2025 18:51:48 +0200
Subject: [PATCH] Check if the data in a block entity is nil, so that there
 won't be an assign to nil map panic

---
 server/session/chunk.go | 9 +++++++++
 server/world/mcdb/db.go | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/server/session/chunk.go b/server/session/chunk.go
index a1f5e8b40..0c717906f 100644
--- a/server/session/chunk.go
+++ b/server/session/chunk.go
@@ -100,6 +100,9 @@ func (s *Session) subChunkEntry(offset protocol.SubChunkOffset, ind int16, col *
 	for pos, b := range col.BlockEntities {
 		if n, ok := b.(world.NBTer); ok && col.Chunk.SubIndex(int16(pos.Y())) == ind {
 			d := n.EncodeNBT()
+			if d == nil {
+				continue
+			}
 			d["x"], d["y"], d["z"] = int32(pos[0]), int32(pos[1]), int32(pos[2])
 			_ = enc.Encode(d)
 		}
@@ -178,6 +181,9 @@ func (s *Session) sendBlobHashes(pos world.ChunkPos, dim world.Dimension, c *chu
 	for bp, b := range blockEntities {
 		if n, ok := b.(world.NBTer); ok {
 			d := n.EncodeNBT()
+			if d == nil {
+				continue
+			}
 			d["x"], d["y"], d["z"] = int32(bp[0]), int32(bp[1]), int32(bp[2])
 			_ = enc.Encode(d)
 		}
@@ -220,6 +226,9 @@ func (s *Session) sendNetworkChunk(pos world.ChunkPos, dim world.Dimension, c *c
 	for bp, b := range blockEntities {
 		if n, ok := b.(world.NBTer); ok {
 			d := n.EncodeNBT()
+			if d == nil {
+				continue
+			}
 			d["x"], d["y"], d["z"] = int32(bp[0]), int32(bp[1]), int32(bp[2])
 			_ = enc.Encode(d)
 		}
diff --git a/server/world/mcdb/db.go b/server/world/mcdb/db.go
index 9c92b6fd5..8cd22fea5 100644
--- a/server/world/mcdb/db.go
+++ b/server/world/mcdb/db.go
@@ -433,6 +433,9 @@ func (db *DB) storeBlockEntities(batch *leveldb.Batch, k dbKey, blockEntities []
 	buf := bytes.NewBuffer(nil)
 	enc := nbt.NewEncoderWithEncoding(buf, nbt.LittleEndian)
 	for _, b := range blockEntities {
+		if b.Data == nil {
+			continue
+		}
 		b.Data["x"], b.Data["y"], b.Data["z"] = int32(b.Pos[0]), int32(b.Pos[1]), int32(b.Pos[2])
 		if err := enc.Encode(b.Data); err != nil {
 			db.conf.Log.Error("store block entities: encode nbt: " + err.Error())