From c723aaf4cf2e41f4ddced72a54686523ebe8fccc Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 21 Mar 2018 20:52:07 -0400
Subject: [PATCH] Fix Dragon Server Crashes

If the dragon tries to find "ground" and hits a hole, or off edge,
it will infinitely keep looking for non air and eventually crash.

diff --git a/src/main/java/net/minecraft/server/DragonControllerLandedFlame.java b/src/main/java/net/minecraft/server/DragonControllerLandedFlame.java
index 1180e7bc1..1906bcfc9 100644
--- a/src/main/java/net/minecraft/server/DragonControllerLandedFlame.java
+++ b/src/main/java/net/minecraft/server/DragonControllerLandedFlame.java
@@ -51,7 +51,7 @@ public class DragonControllerLandedFlame extends AbstractDragonControllerLanded
             double d2 = this.a.bD.locY + (double) (this.a.bD.length / 2.0F);
             BlockPosition.MutableBlockPosition blockposition_mutableblockposition = new BlockPosition.MutableBlockPosition(MathHelper.floor(d0), MathHelper.floor(d2), MathHelper.floor(d1));
 
-            while (this.a.world.isEmpty(blockposition_mutableblockposition)) {
+            while (this.a.world.isEmpty(blockposition_mutableblockposition ) && d2 > 0) { // Paper
                 --d2;
                 blockposition_mutableblockposition.c(MathHelper.floor(d0), MathHelper.floor(d2), MathHelper.floor(d1));
             }
-- 
2.20.1