Store owning Horse in horse inventory. Fixes BUKKIT-4586

src/main/java/net/minecraft/server/EntityHorse.java

@@ -328,7 +328,7 @@ public class EntityHorse extends EntityAnimal implements IInventoryListener {
     public void cH() { // CraftBukkit - private -> public
         InventoryHorseChest inventoryhorsechest = this.inventoryChest;
 
-        this.inventoryChest = new InventoryHorseChest("HorseChest", this.cG());
+        this.inventoryChest = new InventoryHorseChest("HorseChest", this.cG(), this); // CraftBukkit - add this horse
         this.inventoryChest.a(this.getLocalizedName());
         if (inventoryhorsechest != null) {
             inventoryhorsechest.b(this);

src/main/java/net/minecraft/server/InventoryHorseChest.java

@@ -14,9 +14,14 @@ public class InventoryHorseChest extends InventorySubcontainer {
 
     // CraftBukkit start
     public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
-    public org.bukkit.entity.Player player;
+    private EntityHorse horse;
     private int maxStack = MAX_STACK;
 
+    public InventoryHorseChest(String s, int i, EntityHorse horse) {
+        this(s, i);
+        this.horse = horse;
+    }
+
     @Override
     public ItemStack[] getContents() {
         return this.items;
@@ -39,7 +44,7 @@ public class InventoryHorseChest extends InventorySubcontainer {
 
     @Override
     public org.bukkit.inventory.InventoryHolder getOwner() {
-        return this.player;
+        return (org.bukkit.entity.Horse) this.horse.getBukkitEntity();
     }
 
     @Override