From a5a236084f623dca120fd4bdfe41eb20717cf62d Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Fri, 22 Jun 2018 14:31:48 +0100
Subject: [PATCH 1/3] Living: don't applyPostDamageEffects() for dead mobs this
 has already been seen to cause duplication bugs when thorns is used. Anything
 else that modifies inventory during applyPostDamageEffects() when the mob is
 possibly dead will also cause duplication issues.

---
 src/pocketmine/entity/Living.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/pocketmine/entity/Living.php b/src/pocketmine/entity/Living.php
index 55c2a03ae..b5e409d78 100644
--- a/src/pocketmine/entity/Living.php
+++ b/src/pocketmine/entity/Living.php
@@ -469,6 +469,7 @@ abstract class Living extends Entity implements Damageable{
 	/**
 	 * Called after EntityDamageEvent execution to apply post-hurt effects, such as reducing absorption or modifying
 	 * armour durability.
+	 * This will not be called by damage sources causing death.
 	 *
 	 * @param EntityDamageEvent $source
 	 */
@@ -551,9 +552,9 @@ abstract class Living extends Entity implements Damageable{
 			}
 		}
 
-		$this->applyPostDamageEffects($source);
 
 		if($this->isAlive()){
+			$this->applyPostDamageEffects($source);
 			$this->doHitAnimation();
 		}else{
 			$this->startDeathAnimation();

From 6c6630d8457319c5ec2ef08dd96f4123a9636f2d Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Fri, 22 Jun 2018 17:17:40 +0100
Subject: [PATCH 2/3] Player: avoid doing some post-melee attack actions if
 attacking killed the attacker This can happen when an attacker attacks a
 victim wearing thorns armour while having low health, which prior to this
 commit would cause the tool to be duplicated.

---
 src/pocketmine/Player.php | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index c245fa2b2..9f7209b97 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -2529,11 +2529,15 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 							}
 						}
 
-						if($heldItem->onAttackEntity($target) and $this->isSurvival()){ //always fire the hook, even if we are survival
-							$this->inventory->setItemInHand($heldItem);
-						}
+						if($this->isAlive()){
+							//reactive damage like thorns might cause us to be killed by attacking another mob, which
+							//would mean we'd already have dropped the inventory by the time we reached here
+							if($heldItem->onAttackEntity($target) and $this->isSurvival()){ //always fire the hook, even if we are survival
+								$this->inventory->setItemInHand($heldItem);
+							}
 
-						$this->exhaust(0.3, PlayerExhaustEvent::CAUSE_ATTACK);
+							$this->exhaust(0.3, PlayerExhaustEvent::CAUSE_ATTACK);
+						}
 
 						return true;
 					default:

From 484d34fe040827138731d724cacec295f04e46f5 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Fri, 22 Jun 2018 17:47:11 +0100
Subject: [PATCH 3/3] Living: Reset attack cooldown before applying post damage
 effects this fixes things causing damage during post-damage calls coming back
 and being able to do even more damage

---
 src/pocketmine/entity/Living.php | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/pocketmine/entity/Living.php b/src/pocketmine/entity/Living.php
index b5e409d78..6202e9ee4 100644
--- a/src/pocketmine/entity/Living.php
+++ b/src/pocketmine/entity/Living.php
@@ -535,6 +535,8 @@ abstract class Living extends Entity implements Damageable{
 			return;
 		}
 
+		$this->attackTime = 10; //0.5 seconds cooldown
+
 		if($source instanceof EntityDamageByEntityEvent){
 			$e = $source->getDamager();
 			if($source instanceof EntityDamageByChildEntityEvent){
@@ -552,15 +554,12 @@ abstract class Living extends Entity implements Damageable{
 			}
 		}
 
-
 		if($this->isAlive()){
 			$this->applyPostDamageEffects($source);
 			$this->doHitAnimation();
 		}else{
 			$this->startDeathAnimation();
 		}
-
-		$this->attackTime = 10; //0.5 seconds cooldown
 	}
 
 	protected function doHitAnimation() : void{