SPIGOT-6103: Summoning an Eye of Ender throw an Error

nms-patches/EntityEnderSignal.patch

@@ -0,0 +1,20 @@
+--- a/net/minecraft/server/EntityEnderSignal.java
++++ b/net/minecraft/server/EntityEnderSignal.java
+@@ -21,7 +21,7 @@
+ 
+     public void b(ItemStack itemstack) {
+         if (itemstack.getItem() != Items.ENDER_EYE || itemstack.hasTag()) {
+-            this.getDataWatcher().set(EntityEnderSignal.b, SystemUtils.a((Object) itemstack.cloneItemStack(), (itemstack1) -> {
++            this.getDataWatcher().set(EntityEnderSignal.b, SystemUtils.a(itemstack.cloneItemStack(), (itemstack1) -> { // CraftBukkit - decompile error
+                 itemstack1.setCount(1);
+             }));
+         }
+@@ -137,7 +137,7 @@
+     public void loadData(NBTTagCompound nbttagcompound) {
+         ItemStack itemstack = ItemStack.a(nbttagcompound.getCompound("Item"));
+ 
+-        this.b(itemstack);
++        if (!itemstack.isEmpty()) this.b(itemstack); // CraftBukkit - SPIGOT-6103 summon, see also SPIGOT-5474
+     }
+ 
+     @Override