Fixed boats not saving their sails properly.

src/main/java/vazkii/quark/base/asm/ASMHooks.java

@@ -40,6 +40,10 @@ public static void applyRuneColor(float f1, float f2, float f3, float f4) {
 
 	// ===== BOAT SAILS ===== //
 
+	public static void onBoatUpdate(EntityBoat boat) {
+		BoatSails.onBoatUpdate(boat);
+	}
+
 	public static void dropBoatBanner(EntityBoat boat) {
 		BoatSails.dropBoatBanner(boat);
 	}

src/main/java/vazkii/quark/base/asm/ClassTransformer.java

@@ -188,9 +188,10 @@ private static byte[] transformLayerArmorBase(byte[] basicClass) {
 
 	private static byte[] transformEntityBoat(byte[] basicClass) {
 		log("Transforming EntityBoat");
-		MethodSignature sig = new MethodSignature("attackEntityFrom", "func_76986_a", "a", "(Lnet/minecraft/util/DamageSource;F)Z");
-
-		return transform(basicClass, Pair.of(sig, combine(
+		MethodSignature sig1 = new MethodSignature("attackEntityFrom", "func_76986_a", "a", "(Lnet/minecraft/util/DamageSource;F)Z");
+		MethodSignature sig2 = new MethodSignature("onUpdate", "func_70071_h_", "A", "()V");
+
+		byte[] transClass = transform(basicClass, Pair.of(sig1, combine(
 				(AbstractInsnNode node) -> { // Filter
 					return node.getOpcode() == Opcodes.POP;
 				},
@@ -203,6 +204,22 @@ private static byte[] transformEntityBoat(byte[] basicClass) {
 					method.instructions.insertBefore(node, newInstructions);
 					return true;
 				})));
+
+		transClass = transform(transClass, Pair.of(sig2, combine(
+				(AbstractInsnNode node) -> { // Filter
+					return true;
+				},
+				(MethodNode method, AbstractInsnNode node) -> { // Action
+					InsnList newInstructions = new InsnList();
+
+					newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 0));
+					newInstructions.add(new MethodInsnNode(Opcodes.INVOKESTATIC, ASM_HOOKS, "onBoatUpdate", "(Lnet/minecraft/entity/item/EntityBoat;)V"));
+
+					method.instructions.insertBefore(node, newInstructions);
+					return true;
+				})));
+
+		return transClass;
 	}
 
 	private static byte[] transformRenderBoat(byte[] basicClass) {

src/main/java/vazkii/quark/base/handler/DropoffHandler.java

@@ -139,7 +139,7 @@ public void smartDropoff() {
 				int slots = handler.getSlots();
 				for(int i = 0; i < slots; i++) {
 					ItemStack stackAt = handler.getStackInSlot(i);
-					if(stackAt == null)
+					if(stackAt.isEmpty())
 						continue;
 
 					boolean itemEqual = stack.getItem() == stackAt.getItem();
@@ -198,7 +198,7 @@ public void dropoff(DropoffPredicate pred) {
 			for(int i = InventoryPlayer.getHotbarSize(); i < inv.mainInventory.size(); i++) {
 				ItemStack stackAt = inv.getStackInSlot(i);
 
-				if(stackAt != null && !FavoriteItems.isItemFavorited(stackAt)) {
+				if(!stackAt.isEmpty() && !FavoriteItems.isItemFavorited(stackAt)) {
 					ItemStack ret = insert(stackAt, pred);
 					if(!ItemStack.areItemsEqual(stackAt, ret))
 						inv.setInventorySlotContents(i, ret);
@@ -212,7 +212,7 @@ public ItemStack insert(ItemStack stack, DropoffPredicate pred) {
 				IItemHandler handler = pair.getLeft();
 				ret = insertInHandler(handler, stack, pred);
 				if(ret == null)
-					return null;
+					return ItemStack.EMPTY;
 			}
 
 			return ret;
@@ -221,11 +221,11 @@ public ItemStack insert(ItemStack stack, DropoffPredicate pred) {
 		public ItemStack insertInHandler(IItemHandler handler, final ItemStack stack, DropoffPredicate pred) {
 			if(pred.apply(stack, handler)) {
 				ItemStack retStack = ItemHandlerHelper.insertItemStacked(handler, stack, false);
-				if(retStack != null)
+				if(!retStack.isEmpty())
 					retStack = retStack.copy();
 
-				if(retStack == null || retStack.getCount() == 0)
-					return null;
+				if(retStack.isEmpty() || retStack.getCount() == 0)
+					return ItemStack.EMPTY;
 
 				return retStack;
 			}
@@ -249,7 +249,7 @@ public void dropoff(DropoffPredicate pred) {
 			for(int i = inv.getSlots() - 1; i >= 0; i--) {
 				ItemStack stackAt = inv.getStackInSlot(i);
 
-				if(stackAt != null) {
+				if(!stackAt.isEmpty()) {
 					ItemStack copy = stackAt.copy();
 					ItemStack ret = insertInHandler(playerInv, stackAt, pred);
 
@@ -270,7 +270,7 @@ public PlayerInvWrapper(IInventory inv) {
 
 		@Override
 		public ItemStack insertItem(int slot, ItemStack stack, boolean simulate) {
-			if(stack != null)
+			if(!stack.isEmpty())
 				stack = stack.copy();
 
 			return super.insertItem(slot, stack, simulate);

src/main/java/vazkii/quark/vanity/feature/BoatSails.java

@@ -48,19 +48,6 @@ public void onEntityInit(EntityConstructing event) {
 		}
 	}
 
-	@SubscribeEvent
-	public void preUpdate(EntityEvent.CanUpdate event) {
-		if(event.getEntity() instanceof EntityBoat && !event.getEntity().getEntityWorld().isRemote) {
-			ItemStack dataStack = event.getEntity().getDataManager().get(bannerData);
-
-			NBTTagCompound cmp = event.getEntity().getEntityData().getCompoundTag(TAG_BANNER);
-			ItemStack nbtStack = new ItemStack(cmp);
-
-			if(dataStack != nbtStack)
-				event.getEntity().getDataManager().set(bannerData, nbtStack);
-		}
-	}
-
 	@SubscribeEvent
 	public void onEntityInteract(EntityInteract event) {
 		Entity target = event.getTarget();
@@ -103,6 +90,19 @@ public void onEntityInteract(EntityInteract event) {
 	public static ItemStack getBanner(EntityBoat boat) {
 		return boat.getDataManager().get(bannerData);
 	}
+
+	public static void onBoatUpdate(EntityBoat boat) {
+		if(boat.getEntityWorld().isRemote)
+			return;
+
+		ItemStack dataStack = boat.getDataManager().get(bannerData);
+
+		NBTTagCompound cmp = boat.getEntityData().getCompoundTag(TAG_BANNER);
+		ItemStack nbtStack = new ItemStack(cmp);
+
+		if(dataStack != nbtStack)
+			boat.getDataManager().set(bannerData, nbtStack);
+	}
 
 	public static void dropBoatBanner(EntityBoat boat) {
 		if(!ModuleLoader.isFeatureEnabled(BoatSails.class))