From be6a46dbf9ececbcf25d7b384ca2377e47ad70c5 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Sat, 7 Mar 2020 00:07:51 +0000
Subject: [PATCH] Validate tripwire hook placement before update


diff --git a/src/main/java/net/minecraft/server/BlockTripwireHook.java b/src/main/java/net/minecraft/server/BlockTripwireHook.java
index 1b9d889af6..a5e6e94fe0 100644
--- a/src/main/java/net/minecraft/server/BlockTripwireHook.java
+++ b/src/main/java/net/minecraft/server/BlockTripwireHook.java
@@ -149,6 +149,7 @@ public class BlockTripwireHook extends Block {
 
         this.a(world, blockposition, flag4, flag5, flag2, flag3);
         if (!flag) {
+            if (world.getType(blockposition).getBlock() == Blocks.TRIPWIRE_HOOK) // Paper - validate
             world.setTypeAndData(blockposition, (IBlockData) iblockdata3.set(BlockTripwireHook.FACING, enumdirection), 3);
             if (flag1) {
                 this.a(world, blockposition, enumdirection);
-- 
2.25.1