0110-Ensure-correct-attack-damage-on-slot-change.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: necrozma <necrozma999@gmail.com>
Date: Fri, 14 Jul 2023 22:16:17 -0600
Subject: [PATCH] Ensure correct attack damage on slot change


diff --git a/src/main/java/net/minecraft/server/EntityHuman.java b/src/main/java/net/minecraft/server/EntityHuman.java
index 86ab9994079c6e18e3aed885db4171d0d87b4c1a..10284da163e2f1d1b5f12ca738a8fc5580d1373b 100644
--- a/src/main/java/net/minecraft/server/EntityHuman.java
+++ b/src/main/java/net/minecraft/server/EntityHuman.java
@@ -692,6 +692,7 @@ public abstract class EntityHuman extends EntityLiving {
         NBTTagList nbttaglist = nbttagcompound.getList("Inventory", 10);
 
         this.inventory.b(nbttaglist);
+        this.inventory.prevItemInHandIndex = this.inventory.itemInHandIndex; // PandaSpigot
         this.inventory.itemInHandIndex = nbttagcompound.getInt("SelectedItemSlot");
         this.sleeping = nbttagcompound.getBoolean("Sleeping");
         this.sleepTicks = nbttagcompound.getShort("SleepTimer");
diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 94d8f2ffe938bd2d57d0297f9efc43ee55da3ba9..95c92fe5a1f1866da16fb991d29c6de1671684d6 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -34,7 +34,7 @@ public abstract class EntityLiving extends Entity {
 
     private static final UUID a = UUID.fromString("662A6B8D-DA3E-4C1C-8813-96EA6097278D");
     private static final AttributeModifier b = (new AttributeModifier(EntityLiving.a, "Sprinting speed boost", 0.30000001192092896D, 2)).a(false);
-    private AttributeMapBase c;
+    public AttributeMapBase c; // PandaSpigot
     public CombatTracker combatTracker = new CombatTracker(this);
     public final Map<Integer, MobEffect> effects = Maps.newHashMap();
     private final ItemStack[] h = new ItemStack[5];
diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
index 23bd5d11f8b909817855f593adc51d3ca5d9f976..eb56c4ee33c756bc7adfed0e76ef516b5c0566da 100644
--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -963,8 +963,20 @@ public class PlayerConnection implements PacketListenerPlayIn, IUpdatePlayerList
                 return;
             }
             // CraftBukkit end
+            this.player.inventory.prevItemInHandIndex = this.player.inventory.itemInHandIndex; // PandaSpigot
             this.player.inventory.itemInHandIndex = packetplayinhelditemslot.a();
             this.player.resetIdleTimer();
+            // PandaSpigot start - ensure correct attack damage on slot change
+            ItemStack prevItemStack = this.player.inventory.items[this.player.inventory.prevItemInHandIndex];
+            if (prevItemStack != null) {
+                for (AttributeModifier attributemodifier : prevItemStack.B().get("generic.attackDamage")) {
+                    this.player.getAttributeInstance(GenericAttributes.ATTACK_DAMAGE).c(attributemodifier); // remove attack damage from previous held item
+                }
+            }
+            if (this.player.inventory.getItemInHand() != null) {
+                ((EntityLiving) this.player).c.b(this.player.inventory.getItemInHand().B()); // apply attack damage from current held item
+            }
+            // PandaSpigot end
         } else {
             PlayerConnection.c.warn(this.player.getName() + " tried to set an invalid carried item");
             this.disconnect("Invalid hotbar selection (Hacking?)"); // CraftBukkit //Spigot "Nope" -> Descriptive reason
diff --git a/src/main/java/net/minecraft/server/PlayerInventory.java b/src/main/java/net/minecraft/server/PlayerInventory.java
index 76fa51d97e9a938d4198bbe657d77900f6327744..3a8c600b7d80a46be0c33f0f6b50b751b764eb49 100644
--- a/src/main/java/net/minecraft/server/PlayerInventory.java
+++ b/src/main/java/net/minecraft/server/PlayerInventory.java
@@ -14,6 +14,7 @@ public class PlayerInventory implements IInventory {
     public ItemStack[] items = new ItemStack[36];
     public ItemStack[] armor = new ItemStack[4];
     public int itemInHandIndex;
+    public int prevItemInHandIndex; // PandaSpigot
     public EntityHuman player;
     private ItemStack f;
     public boolean e;
@@ -571,6 +572,7 @@ public class PlayerInventory implements IInventory {
             this.armor[i] = ItemStack.b(playerinventory.armor[i]);
         }
 
+        this.prevItemInHandIndex = playerinventory.prevItemInHandIndex; // PandaSpigot
         this.itemInHandIndex = playerinventory.itemInHandIndex;
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryPlayer.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryPlayer.java
index dba8d5ba1df8c04d8988af9b1e3329269e9a1942..202975055eda4e66e922b7d67d84ad30973591b0 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryPlayer.java
@@ -81,6 +81,7 @@ public class CraftInventoryPlayer extends CraftInventory implements org.bukkit.i
 
     public void setHeldItemSlot(int slot) {
         Validate.isTrue(slot >= 0 && slot < PlayerInventory.getHotbarSize(), "Slot is not between 0 and 8 inclusive");
+        this.getInventory().prevItemInHandIndex = this.getInventory().itemInHandIndex; // PandaSpigot
         this.getInventory().itemInHandIndex = slot;
         ((CraftPlayer) this.getHolder()).getHandle().playerConnection.sendPacket(new PacketPlayOutHeldItemSlot(slot));
     }