From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 1 Jun 2016 23:29:17 -0400
Subject: [PATCH] Reset Ender Crystals on Dragon Spawn

Crystals can end up in a bad state in certain conditions which causes
an exception on the expected number of crystals going negative.

This ensures the crystals/pillars are in expected state when the dragon spawns.

See #3522

diff --git a/src/main/java/net/minecraft/world/level/dimension/end/EnderDragonBattle.java b/src/main/java/net/minecraft/world/level/dimension/end/EnderDragonBattle.java
index 0869af4670f040344f5b6c2c10bff5e5226f707c..c6283489dcb6e13f0d618971614aeadaee2e3007 100644
--- a/src/main/java/net/minecraft/world/level/dimension/end/EnderDragonBattle.java
+++ b/src/main/java/net/minecraft/world/level/dimension/end/EnderDragonBattle.java
@@ -445,6 +445,7 @@ public class EnderDragonBattle {
         entityenderdragon.setPositionRotation(0.0D, 128.0D, 0.0D, this.world.random.nextFloat() * 360.0F, 0.0F);
         this.world.addEntity(entityenderdragon);
         this.dragonUUID = entityenderdragon.getUniqueID();
+        this.resetCrystals(); // Paper
         return entityenderdragon;
     }