From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: lexikiq <noellekiq@gmail.com>
Date: Mon, 21 Jun 2021 23:21:58 -0400
Subject: [PATCH] Preserve overstacked loot

Preserves overstacked items in loot tables, such as shulker box drops, to prevent the items
from being deleted (as they'd overflow past the bounds of the container)-- or worse, causing
chunk bans via the large amount of NBT created by unstacking the items.

Fixes GH-5140 and GH-4748.

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 8cb3767551d36cc2c7c07548182d817f9843bf50..e5543b3a261f80bd9b0346d595a62b5458d9b229 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -853,6 +853,11 @@ public class PaperWorldConfig {
         allowPlayerCrammingDamage = getBoolean("allow-player-cramming-damage", allowPlayerCrammingDamage);
     }
 
+    public boolean splitOverstackedLoot = true;
+    private void splitOverstackedLoot() {
+        splitOverstackedLoot = getBoolean("split-overstacked-loot", splitOverstackedLoot);
+    }
+
     private Table<String, String, Integer> sensorTickRates;
     private Table<String, String, Integer> behaviorTickRates;
     private void tickRates() {
diff --git a/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java b/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
index 276c444a0fddb6962818635d5fc7721a56b30784..4f240fc74fb9551d752855dcdf2a376ff30f536b 100644
--- a/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
+++ b/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
@@ -54,9 +54,17 @@ public class LootTable {
         this.compositeFunction = LootItemFunctions.compose(functions);
     }
 
+    @Deprecated // Paper - preserve overstacked items
     public static Consumer<ItemStack> createStackSplitter(Consumer<ItemStack> lootConsumer) {
+    // Paper start - preserve overstacked items
+        return createStackSplitter(lootConsumer, null);
+    }
+
+    public static Consumer<ItemStack> createStackSplitter(Consumer<ItemStack> lootConsumer, @org.jetbrains.annotations.Nullable net.minecraft.server.level.ServerLevel world) {
+        boolean skipSplitter = world != null && !world.paperConfig.splitOverstackedLoot;
+    // Paper end
         return (itemstack) -> {
-            if (itemstack.getCount() < itemstack.getMaxStackSize()) {
+            if (skipSplitter || itemstack.getCount() < itemstack.getMaxStackSize()) { // Paper - preserve overstacked items
                 lootConsumer.accept(itemstack);
             } else {
                 int i = itemstack.getCount();
@@ -93,7 +101,7 @@ public class LootTable {
     }
 
     public void getRandomItems(LootContext context, Consumer<ItemStack> lootConsumer) {
-        this.getRandomItemsRaw(context, LootTable.createStackSplitter(lootConsumer));
+        this.getRandomItemsRaw(context, LootTable.createStackSplitter(lootConsumer, context.getLevel())); // Paper - preserve overstacked items
     }
 
     public List<ItemStack> getRandomItems(LootContext context) {
diff --git a/src/main/java/net/minecraft/world/level/storage/loot/functions/SetContainerContents.java b/src/main/java/net/minecraft/world/level/storage/loot/functions/SetContainerContents.java
index 057676201aa2d19032537832849f3857425d357a..b5c6b7280a9c6964e2ad4aa9bd4517146c98e727 100644
--- a/src/main/java/net/minecraft/world/level/storage/loot/functions/SetContainerContents.java
+++ b/src/main/java/net/minecraft/world/level/storage/loot/functions/SetContainerContents.java
@@ -46,7 +46,7 @@ public class SetContainerContents extends LootItemConditionalFunction {
             NonNullList<ItemStack> nonNullList = NonNullList.create();
             this.entries.forEach((entry) -> {
                 entry.expand(context, (choice) -> {
-                    choice.createItemStack(LootTable.createStackSplitter(nonNullList::add), context);
+                    choice.createItemStack(LootTable.createStackSplitter(nonNullList::add, context.getLevel()), context); // Paper - preserve overstacked items
                 });
             });
             CompoundTag compoundTag = new CompoundTag();