From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Tue, 24 Sep 2019 16:03:00 -0700
Subject: [PATCH] Fix MC-161754

#NOTE: the mojira issue is marked as fixed in 20w12a

Fixes https://github.com/PaperMC/Paper/issues/2580

We can use an entity valid check since this method is invoked for
each inventory iteraction (thanks to CB) and on player tick (vanilla).

diff --git a/src/main/java/net/minecraft/world/inventory/HorseInventoryMenu.java b/src/main/java/net/minecraft/world/inventory/HorseInventoryMenu.java
index f3e17f00f09feb4df4274b09bc7fa3c3022a5fbb..ffc596d8db77aaeed43f79b895bf4a1c7baeeab2 100644
--- a/src/main/java/net/minecraft/world/inventory/HorseInventoryMenu.java
+++ b/src/main/java/net/minecraft/world/inventory/HorseInventoryMenu.java
@@ -95,7 +95,7 @@ public class HorseInventoryMenu extends AbstractContainerMenu {
 
     @Override
     public boolean stillValid(Player player) {
-        return !this.horse.hasInventoryChanged(this.horseContainer) && this.horseContainer.stillValid(player) && this.horse.isAlive() && this.horse.distanceTo((Entity) player) < 8.0F;
+        return !this.horse.hasInventoryChanged(this.horseContainer) && this.horseContainer.stillValid(player) && (this.horse.isAlive() && this.horse.valid) && this.horse.distanceTo((Entity) player) < 8.0F; // Paper - Fix MC-161754
     }
 
     private boolean hasChest(AbstractHorse horse) {