Paper/patches/server/0840-Prevent-empty-items-from-being-added-to-world.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
Date: Wed, 15 Jun 2022 21:52:57 -0400
Subject: [PATCH] Prevent empty items from being added to world

The previous solution caused a bunch of bandaid fixes inorder to resolve edge cases where minecraft/the api might spawn items that are air.
Just simply prevent them from being added to the world instead.

diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 653c9c41ab7c5cd332565436564396d18f26c17c..06df21e55fdb70558b85fc095a04b3bb64fbe770 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1645,6 +1645,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
             // WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getKey(entity.getType())); // CraftBukkit
             return false;
         } else {
+            if (entity instanceof net.minecraft.world.entity.item.ItemEntity itemEntity && itemEntity.getItem().isEmpty()) return false; // Paper - Prevent empty items from being added
             // Paper start - capture all item additions to the world
             if (captureDrops != null && entity instanceof net.minecraft.world.entity.item.ItemEntity) {
                 captureDrops.add((net.minecraft.world.entity.item.ItemEntity) entity);
diff --git a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
index 8a2c135ee7c6fe60a2debf7a7b02fb9ffc3d2c2f..b1ae4702d7165794600b257fe8563a4ac48d922c 100644
--- a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
+++ b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
@@ -515,7 +515,7 @@ public class ItemEntity extends Entity implements TraceableEntity {
     }
 
     public void setItem(ItemStack stack) {
-        com.google.common.base.Preconditions.checkArgument(!stack.isEmpty(), "Cannot drop air"); // CraftBukkit
+        // com.google.common.base.Preconditions.checkArgument(!stack.isEmpty(), "Cannot drop air"); // CraftBukkit // Paper - Remove check
         this.getEntityData().set(ItemEntity.DATA_ITEM, stack);
         this.getEntityData().markDirty(ItemEntity.DATA_ITEM); // CraftBukkit - SPIGOT-4591, must mark dirty
         this.despawnRate = this.level().paperConfig().entities.spawning.altItemDespawnRate.enabled ? this.level().paperConfig().entities.spawning.altItemDespawnRate.items.getOrDefault(stack.getItem(), this.level().spigotConfig.itemDespawnRate) : this.level().spigotConfig.itemDespawnRate; // Paper