From 6cc9dca44a2a2be130d0382b38f35f4de8109f7f 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 c53518a47..6f34d8aea 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