From d8b88fa191c6889982feff85a41cdcfc7207b11c Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Mon, 15 Apr 2019 02:24:52 +0100
Subject: [PATCH] Handle bad chunks more gracefully

Prior to this change the server would crash when attempting to load a
chunk from a region with bad data.

After this change the server will defer back to vanilla behavior. At
this time, that means attempting to generate a chunk in its place
(and occasionally just not generating anything and leaving small
holes in the world (This statement might not be accurate as of 1.13.x)).

Should Mojang choose to alter this behavior in the future, this change
will simply defer to whatever that new behavior is.

diff --git a/src/main/java/net/minecraft/server/RegionFileCache.java b/src/main/java/net/minecraft/server/RegionFileCache.java
index b61864641..d39d49944 100644
--- a/src/main/java/net/minecraft/server/RegionFileCache.java
+++ b/src/main/java/net/minecraft/server/RegionFileCache.java
@@ -171,8 +171,21 @@ public abstract class RegionFileCache implements AutoCloseable {
     private static NBTTagCompound readOversizedChunk(RegionFile regionfile, ChunkCoordIntPair chunkCoordinate) throws IOException {
         synchronized (regionfile) {
             try (DataInputStream datainputstream = regionfile.getReadStream(chunkCoordinate)) {
-                NBTTagCompound oversizedData = regionfile.getOversizedData(chunkCoordinate.x, chunkCoordinate.z);
-                NBTTagCompound chunk = NBTCompressedStreamTools.readNBT(datainputstream);
+                // Paper start - Handle bad chunks more gracefully - also handle similarly with oversized data
+                NBTTagCompound oversizedData = null;
+
+                try {
+                    oversizedData = regionfile.getOversizedData(chunkCoordinate.x, chunkCoordinate.z);
+                } catch (Exception ex) {}
+
+                NBTTagCompound chunk;
+
+                try {
+                    chunk = NBTCompressedStreamTools.readNBT(datainputstream);
+                } catch (final Exception ex) {
+                    return null;
+                }
+                // Paper end
                 if (oversizedData == null) {
                     return chunk;
                 }
@@ -231,8 +244,13 @@ public abstract class RegionFileCache implements AutoCloseable {
 
         try {
             if (datainputstream != null) {
-                nbttagcompound = NBTCompressedStreamTools.a(datainputstream);
-                return nbttagcompound;
+                // Paper start - Handle bad chunks more gracefully
+                try {
+                    return NBTCompressedStreamTools.a(datainputstream);
+                } catch (Exception ex) {
+                    return null;
+                }
+                // Paper end
             }
 
             nbttagcompound = null;
-- 
2.21.0