PaperMC/nms-patches/ItemSnowball.patch

--- a/net/minecraft/server/ItemSnowball.java
+++ b/net/minecraft/server/ItemSnowball.java
@@ -10,19 +10,31 @@
     public InteractionResultWrapper<ItemStack> a(World world, EntityHuman entityhuman, EnumHand enumhand) {
         ItemStack itemstack = entityhuman.b(enumhand);
 
-        world.playSound((EntityHuman) null, entityhuman.locX(), entityhuman.locY(), entityhuman.locZ(), SoundEffects.ENTITY_SNOWBALL_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (ItemSnowball.i.nextFloat() * 0.4F + 0.8F));
+        // CraftBukkit - moved down
+        // world.playSound((EntityHuman) null, entityhuman.locX(), entityhuman.locY(), entityhuman.locZ(), SoundEffects.ENTITY_SNOWBALL_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (ItemSnowball.i.nextFloat() * 0.4F + 0.8F));
         if (!world.isClientSide) {
             EntitySnowball entitysnowball = new EntitySnowball(world, entityhuman);
 
             entitysnowball.setItem(itemstack);
             entitysnowball.a(entityhuman, entityhuman.pitch, entityhuman.yaw, 0.0F, 1.5F, 1.0F);
-            world.addEntity(entitysnowball);
+            if (world.addEntity(entitysnowball)) {
+                if (!entityhuman.abilities.canInstantlyBuild) {
+                    itemstack.subtract(1);
+                }
+
+                world.playSound((EntityHuman) null, entityhuman.locX(), entityhuman.locY(), entityhuman.locZ(), SoundEffects.ENTITY_SNOWBALL_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (ItemSnowball.i.nextFloat() * 0.4F + 0.8F));            } else if (entityhuman instanceof EntityPlayer) {
+                ((EntityPlayer) entityhuman).getBukkitEntity().updateInventory();
+            }
         }
+        // CraftBukkit end
 
         entityhuman.b(StatisticList.ITEM_USED.b(this));
+        // CraftBukkit start - moved up
+        /*
         if (!entityhuman.abilities.canInstantlyBuild) {
             itemstack.subtract(1);
         }
+        */
 
         return InteractionResultWrapper.success(itemstack);
     }