Fix empty data attachments being saved. (#3588)

* Fix empty data attachments being saved. * Checkstyle (cherry picked from commit b90db57)
FabricMC · Feb 12, 2024 · 6de560b · 6de560b
1 parent 2ee1668
commit 6de560b
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Showing 2 changed files with 29 additions and 4 deletions.
diff --git a/...t-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/AttachmentSerializingImpl.java b/...t-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/AttachmentSerializingImpl.java
@@ -39,7 +39,7 @@ public class AttachmentSerializingImpl {
 
 	@SuppressWarnings("unchecked")
 	public static void serializeAttachmentData(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup, @Nullable IdentityHashMap<AttachmentType<?>, ?> attachments) {
-		if (attachments == null) {
+		if (attachments == null || attachments.isEmpty()) {
 			return;
 		}
 
@@ -64,10 +64,10 @@ public static void serializeAttachmentData(NbtCompound nbt, RegistryWrapper.Wrap
 		nbt.put(AttachmentTarget.NBT_ATTACHMENT_KEY, compound);
 	}
 
+	@Nullable
 	public static IdentityHashMap<AttachmentType<?>, Object> deserializeAttachmentData(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup) {
-		var attachments = new IdentityHashMap<AttachmentType<?>, Object>();
-
 		if (nbt.contains(AttachmentTarget.NBT_ATTACHMENT_KEY, NbtElement.COMPOUND_TYPE)) {
+			var attachments = new IdentityHashMap<AttachmentType<?>, Object>();
 			NbtCompound compound = nbt.getCompound(AttachmentTarget.NBT_ATTACHMENT_KEY);
 
 			for (String key : compound.getKeys()) {
@@ -93,9 +93,15 @@ public static IdentityHashMap<AttachmentType<?>, Object> deserializeAttachmentDa
 							);
 				}
 			}
+
+			if (attachments.isEmpty()) {
+				return null;
+			}
+
+			return attachments;
 		}
 
-		return attachments;
+		return null;
 	}
 
 	public static boolean hasPersistentAttachments(@Nullable IdentityHashMap<AttachmentType<?>, ?> map) {

diff --git a/...hment-api-v1/src/test/java/net/fabricmc/fabric/test/attachment/CommonAttachmentTests.java b/...hment-api-v1/src/test/java/net/fabricmc/fabric/test/attachment/CommonAttachmentTests.java
@@ -147,6 +147,25 @@ void testStaticReadWrite() {
 		assertEquals(0.5d, entry.getValue());
 	}
 
+	@Test
+	void deserializeNull() {
+		var nbt = new NbtCompound();
+		assertNull(AttachmentSerializingImpl.deserializeAttachmentData(nbt, null));
+
+		nbt.put(new Identifier("test").toString(), new NbtCompound());
+		assertNull(AttachmentSerializingImpl.deserializeAttachmentData(nbt, null));
+	}
+
+	@Test
+	void serializeNullOrEmpty() {
+		var nbt = new NbtCompound();
+		AttachmentSerializingImpl.serializeAttachmentData(nbt, null, null);
+		assertFalse(nbt.contains(AttachmentTarget.NBT_ATTACHMENT_KEY));
+
+		AttachmentSerializingImpl.serializeAttachmentData(nbt, null, new IdentityHashMap<>());
+		assertFalse(nbt.contains(AttachmentTarget.NBT_ATTACHMENT_KEY));
+	}
+
 	@Test
 	void testEntityCopy() {
 		AttachmentType<Boolean> notCopiedOnRespawn = AttachmentRegistry.create(