Add per-AttachmentType sync size limits & Allow modifying large payload max size

fabric-data-attachment-api-v1/src/main/java/net/fabricmc/fabric/api/attachment/v1/AttachmentRegistry.java

@@ -159,6 +159,18 @@ public interface Builder<A> {
 		 */
 		AttachmentRegistry.Builder<A> syncWith(StreamCodec<? super RegistryFriendlyByteBuf, A> packetCodec, AttachmentSyncPredicate syncPredicate);
 
+		/**
+		 * Declares that this attachment type may be automatically synchronized with some clients, as determined by {@code syncPredicate}.
+		 *
+		 * <p>The max size limit should be increased with care, as syncing large amounts of data may result in network lag and excessive bandwidth usage.
+		 *
+		 * @param packetCodec the codec used to serialize the attachment data over the network
+		 * @param syncPredicate an {@link AttachmentSyncPredicate} determining with which clients to synchronize data
+		 * @param maxSyncBytes the max number of data bytes that can be synced, defaults to 1 MiB
+		 * @return the builder
+		 */
+		AttachmentRegistry.Builder<A> syncWith(StreamCodec<? super RegistryFriendlyByteBuf, A> packetCodec, AttachmentSyncPredicate syncPredicate, int maxSyncBytes);
+
 		/**
 		 * Builds and registers the {@link AttachmentType}.
 		 *

fabric-data-attachment-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/AttachmentRegistryImpl.java

@@ -36,6 +36,7 @@
 import net.fabricmc.fabric.api.attachment.v1.AttachmentRegistry;
 import net.fabricmc.fabric.api.attachment.v1.AttachmentSyncPredicate;
 import net.fabricmc.fabric.api.attachment.v1.AttachmentType;
+import net.fabricmc.fabric.impl.attachment.sync.AttachmentChange;
 import net.fabricmc.fabric.impl.attachment.sync.AttachmentSync;
 
 public final class AttachmentRegistryImpl {
@@ -84,6 +85,7 @@ public static class BuilderImpl<A> implements AttachmentRegistry.Builder<A> {
 		@Nullable
 		private AttachmentSyncPredicate syncPredicate = null;
 		private boolean copyOnDeath = false;
+		private int maxSyncBytes = 1024 * 1024; // 1 MiB
 
 		@Override
 		public AttachmentRegistry.Builder<A> persistent(Codec<A> codec) {
@@ -107,7 +109,7 @@ public AttachmentRegistry.Builder<A> initializer(Supplier<A> initializer) {
 			return this;
 		}
 
-		@Deprecated
+		@Override
 		public AttachmentRegistry.Builder<A> syncWith(StreamCodec<? super RegistryFriendlyByteBuf, A> packetCodec, AttachmentSyncPredicate syncPredicate) {
 			Objects.requireNonNull(packetCodec, "packet codec cannot be null");
 			Objects.requireNonNull(syncPredicate, "sync predicate cannot be null");
@@ -117,6 +119,20 @@ public AttachmentRegistry.Builder<A> syncWith(StreamCodec<? super RegistryFriend
 			return this;
 		}
 
+		@Override
+		public AttachmentRegistry.Builder<A> syncWith(StreamCodec<? super RegistryFriendlyByteBuf, A> packetCodec, AttachmentSyncPredicate syncPredicate, int maxSyncBytes) {
+			syncWith(packetCodec, syncPredicate);
+
+			if (maxSyncBytes > AttachmentChange.MAX_DATA_SIZE_IN_BYTES) {
+				throw new IllegalArgumentException("max sync bytes cannot be greater than " + AttachmentChange.MAX_DATA_SIZE_IN_BYTES);
+			} else if (maxSyncBytes <= 0) {
+				throw new IllegalArgumentException("max sync bytes must be positive");
+			}
+
+			this.maxSyncBytes = maxSyncBytes;
+			return this;
+		}
+
 		@Override
 		public AttachmentType<A> buildAndRegister(Identifier id) {
 			Objects.requireNonNull(id, "identifier cannot be null");
@@ -136,6 +152,7 @@ public AttachmentType<A> buildAndRegister(Identifier id) {
 					persistenceCodec,
 					packetCodec,
 					syncPredicate,
+					maxSyncBytes,
 					copyOnDeath
 			);
 			register(id, attachment);

fabric-data-attachment-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/AttachmentTypeImpl.java

@@ -34,6 +34,7 @@ public record AttachmentTypeImpl<A>(
 		@Nullable Codec<A> persistenceCodec,
 		@Nullable StreamCodec<? super RegistryFriendlyByteBuf, A> packetCodec,
 		@Nullable AttachmentSyncPredicate syncPredicate,
+		int maxSyncBytes,
 		boolean copyOnDeath
 ) implements AttachmentType<A> {
 	@Override

fabric-data-attachment-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/sync/AttachmentChange.java

@@ -45,7 +45,6 @@
 import net.fabricmc.fabric.impl.attachment.AttachmentRegistryImpl;
 import net.fabricmc.fabric.impl.attachment.AttachmentTypeImpl;
 import net.fabricmc.fabric.impl.attachment.sync.s2c.AttachmentSyncPayloadS2C;
-import net.fabricmc.fabric.mixin.attachment.ServerboundCustomPayloadPacketAccessor;
 import net.fabricmc.fabric.mixin.attachment.VarIntAccessor;
 import net.fabricmc.fabric.mixin.networking.accessor.ServerCommonPacketListenerImplAccessor;
 
@@ -60,7 +59,7 @@ public record AttachmentChange(AttachmentTargetInfo<?> targetInfo, AttachmentTyp
 			AttachmentChange::new
 	);
 	private static final int MAX_PADDING_SIZE_IN_BYTES = AttachmentTargetInfo.MAX_SIZE_IN_BYTES + AttachmentSync.MAX_IDENTIFIER_SIZE;
-	private static final int MAX_DATA_SIZE_IN_BYTES = ServerboundCustomPayloadPacketAccessor.getMaxPayloadSize() - MAX_PADDING_SIZE_IN_BYTES;
+	public static final int MAX_DATA_SIZE_IN_BYTES = AttachmentSync.MAX_ATTACHMENT_SYNC_PAYLOAD_SIZE - MAX_PADDING_SIZE_IN_BYTES;
 
 	@SuppressWarnings("unchecked")
 	public static AttachmentChange create(AttachmentTargetInfo<?> targetInfo, AttachmentType<?> type, @Nullable Object value, RegistryAccess dynamicRegistryManager) {
@@ -77,13 +76,15 @@ public static AttachmentChange create(AttachmentTargetInfo<?> targetInfo, Attach
 			buf.writeBoolean(false);
 		}
 
-		byte[] encoded = buf.array();
+		byte[] encoded = new byte[buf.readableBytes()]; // buf.array() will return the backing array directly, which may contain unused space
+		buf.readBytes(encoded);
+		int maxSyncBytes = ((AttachmentTypeImpl<?>) type).maxSyncBytes();
 
-		if (encoded.length > MAX_DATA_SIZE_IN_BYTES) {
-			throw new IllegalArgumentException("Data for attachment '%s' was too big (%d bytes, over maximum %d)".formatted(
+		if (encoded.length > maxSyncBytes) {
+			throw new IllegalArgumentException("Data for attachment '%s' was too big (%d bytes, over maximum %d). This limit can be configured during attachment registration.".formatted(
 					type.identifier(),
 					encoded.length,
-					MAX_DATA_SIZE_IN_BYTES
+					maxSyncBytes
 			));
 		}
 

fabric-data-attachment-api-v1/src/main/java/net/fabricmc/fabric/impl/attachment/sync/AttachmentSync.java

@@ -46,6 +46,7 @@
 
 public class AttachmentSync implements ModInitializer {
 	public static final int MAX_IDENTIFIER_SIZE = 256;
+	public static final int MAX_ATTACHMENT_SYNC_PAYLOAD_SIZE = Integer.MAX_VALUE;
 
 	public static AcceptedAttachmentsPayloadC2S createResponsePayload() {
 		return new AcceptedAttachmentsPayloadC2S(AttachmentRegistryImpl.getSyncableAttachments());
@@ -103,7 +104,7 @@ public void onInitialize() {
 		});
 
 		// Play
-		PayloadTypeRegistry.playS2C().register(AttachmentSyncPayloadS2C.ID, AttachmentSyncPayloadS2C.CODEC);
+		PayloadTypeRegistry.playS2C().registerLarge(AttachmentSyncPayloadS2C.ID, AttachmentSyncPayloadS2C.CODEC, MAX_ATTACHMENT_SYNC_PAYLOAD_SIZE);
 
 		ServerPlayerEvents.JOIN.register((player) -> {
 			List<AttachmentChange> changes = new ArrayList<>();

fabric-data-attachment-api-v1/src/main/resources/fabric-data-attachment-api-v1.mixins.json

@@ -9,7 +9,6 @@
     "PlayerChunkSenderMixin",
     "ChunkAccessMixin",
     "ConnectionMixin",
-    "ServerboundCustomPayloadPacketAccessor",
     "EntityMixin",
     "SerializableChunkDataMixin",
     "ServerLevelMixin",

fabric-data-attachment-api-v1/src/testmod/java/net/fabricmc/fabric/test/attachment/AttachmentTestMod.java

@@ -16,6 +16,8 @@
 
 package net.fabricmc.fabric.test.attachment;
 
+import java.util.stream.LongStream;
+
 import com.mojang.serialization.Codec;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -28,6 +30,7 @@
 import net.minecraft.resources.Identifier;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.util.ExtraCodecs;
+import net.minecraft.util.RandomSource;
 import net.minecraft.world.InteractionResult;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.Items;
@@ -95,6 +98,13 @@ public class AttachmentTestMod implements ModInitializer {
 					.persistent(ExtraCodecs.NON_NEGATIVE_INT)
 					.syncWith(ByteBufCodecs.INT, AttachmentSyncPredicate.targetOnly())
 	);
+	public static final long[] LARGE_DATA = LongStream.generate(RandomSource.create(16554)::nextLong).limit((10 * 1024 * 1024) / 8).toArray();
+	public static final AttachmentType<long[]> SYNCED_LARGE = AttachmentRegistry.create(
+			Identifier.fromNamespaceAndPath(MOD_ID, "synced_large"),
+			builder -> builder
+					.initializer(() -> LARGE_DATA)
+					.syncWith(ByteBufCodecs.LONG_ARRAY, AttachmentSyncPredicate.all(), 10 * 1024 * 1024 + 4) // 10 MiB + int length
+	);
 
 	@Override
 	public void onInitialize() {
@@ -115,6 +125,14 @@ public void onInitialize() {
 					player.displayClientMessage(Component.literal("Attached"), false);
 					return InteractionResult.SUCCESS;
 				}
+			} else if (player.getItemInHand(hand).getItem() == Items.GOLDEN_CARROT) {
+				BlockEntity blockEntity = world.getBlockEntity(hitResult.getBlockPos());
+
+				if (blockEntity != null) {
+					blockEntity.getAttachedOrCreate(SYNCED_LARGE);
+					player.displayClientMessage(Component.literal("Attached LARGE"), false);
+					return InteractionResult.SUCCESS;
+				}
 			}
 
 			return InteractionResult.PASS;