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.

Spigot-Server-Patches/0280-Fix-Dragon-Server-Crashes.patch

@@ -0,0 +1,24 @@
+From 5f1caeb5976c2ad194ad44ff269bea5caf7b39b4 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 054a7ef6c..deee5c4cc 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.bw.locY + (double) (this.a.bw.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));
+             }
+-- 
+2.16.2
+

scripts/importmcdev.sh

@@ -63,6 +63,7 @@ import DataConverterMaterialId
 import DataInspectorBlockEntity
 import DataPalette
 import DefinedStructure
+import DragonControllerLandedFlame
 import EnchantmentManager
 import Enchantments
 import EntityLlama