From 56a6cfc2fb3db91c37a6505fcbaa342458f8a5b7 Mon Sep 17 00:00:00 2001
From: KrystilizeNevaDies <tyreece@rozycki.family>
Date: Tue, 29 Aug 2023 10:01:30 +1000
Subject: [PATCH] Allow serialisation of empty nbt components

---
 src/main/java/net/minestom/server/tag/Serializers.java    | 4 +++-
 src/main/java/net/minestom/server/tag/TagHandlerImpl.java | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/main/java/net/minestom/server/tag/Serializers.java b/src/main/java/net/minestom/server/tag/Serializers.java
index 3a13bd436..40258e9ce 100644
--- a/src/main/java/net/minestom/server/tag/Serializers.java
+++ b/src/main/java/net/minestom/server/tag/Serializers.java
@@ -12,6 +12,8 @@ import java.util.function.Function;
  * Basic serializers for {@link Tag tags}.
  */
 final class Serializers {
+    static final boolean SERIALIZE_EMPTY_COMPOUND = System.getProperty("minestom.serialization.serialize-nbt-compound", "false").equalsIgnoreCase("true");
+
     static final Entry<Byte, NBTByte> BYTE = new Entry<>(NBTType.TAG_Byte, NBTByte::getValue, NBT::Byte);
     static final Entry<Boolean, NBTByte> BOOLEAN = new Entry<>(NBTType.TAG_Byte, NBTByte::asBoolean, NBT::Boolean);
     static final Entry<Short, NBTShort> SHORT = new Entry<>(NBTType.TAG_Short, NBTShort::getValue, NBT::Short);
@@ -31,7 +33,7 @@ final class Serializers {
     static <T> Entry<T, NBTCompound> fromTagSerializer(TagSerializer<T> serializer) {
         return new Serializers.Entry<>(NBTType.TAG_Compound,
                 (NBTCompound compound) -> {
-                    if (compound.isEmpty()) return null;
+                    if ((!SERIALIZE_EMPTY_COMPOUND) && compound.isEmpty()) return null;
                     return serializer.read(TagHandler.fromCompound(compound));
                 },
                 (value) -> {
diff --git a/src/main/java/net/minestom/server/tag/TagHandlerImpl.java b/src/main/java/net/minestom/server/tag/TagHandlerImpl.java
index dc80a01f9..67ec75db6 100644
--- a/src/main/java/net/minestom/server/tag/TagHandlerImpl.java
+++ b/src/main/java/net/minestom/server/tag/TagHandlerImpl.java
@@ -281,7 +281,7 @@ final class TagHandlerImpl implements TagHandler {
                 this.entries.forValues(entry -> {
                     final Tag tag = entry.tag;
                     final NBT nbt = entry.updatedNbt();
-                    if (!tag.entry.isPath() || !((NBTCompound) nbt).isEmpty()) {
+                    if (!tag.entry.isPath() || (!Serializers.SERIALIZE_EMPTY_COMPOUND) && !((NBTCompound) nbt).isEmpty()) {
                         tmp.put(tag.getKey(), nbt);
                     }
                 });
@@ -313,7 +313,7 @@ final class TagHandlerImpl implements TagHandler {
                 tmp.put(tag.getKey(), nbt);
                 entries.put(tag.index, valueToEntry(result, tag, value));
             });
-            if (tmp.isEmpty() && parent != null)
+            if ((!Serializers.SERIALIZE_EMPTY_COMPOUND) && tmp.isEmpty() && parent != null)
                 return null; // Empty child node
             result.compound = tmp.toCompound();
             return result;