Paper/patches/server/0579-fix-PlayerItemHeldEvent-firing-twice.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: chickeneer <emcchickeneer@gmail.com>
Date: Thu, 22 Apr 2021 19:02:07 -0700
Subject: [PATCH] fix PlayerItemHeldEvent firing twice


diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index d45c8e234332978154f1fafad6ed5edf927f6103..fe0d6841b6ad76fc4a8cf8181393a9707a98423d 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -1894,6 +1894,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
         PacketUtils.ensureRunningOnSameThread(packet, this, this.player.serverLevel());
         if (this.player.isImmobile()) return; // CraftBukkit
         if (packet.getSlot() >= 0 && packet.getSlot() < Inventory.getSelectionSize()) {
+            if (packet.getSlot() == this.player.getInventory().selected) { return; } // Paper - don't fire itemheldevent when there wasn't a slot change
             PlayerItemHeldEvent event = new PlayerItemHeldEvent(this.getCraftPlayer(), this.player.getInventory().selected, packet.getSlot());
             this.cserver.getPluginManager().callEvent(event);
             if (event.isCancelled()) {