From ea03a714afb61798851be72f35684477ce4e5710 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 17e76815ad..369aaa84c4 100644
--- a/src/main/java/net/minecraft/server/RegionFileCache.java
+++ b/src/main/java/net/minecraft/server/RegionFileCache.java
@@ -171,8 +171,20 @@ public class RegionFileCache {
     private static NBTTagCompound readOversizedChunk(RegionFile regionfile, int i, int j) throws IOException {
         synchronized (regionfile) {
             try (DataInputStream datainputstream = regionfile.getReadStream(i & 31, j & 31)) {
-                NBTTagCompound oversizedData = regionfile.getOversizedData(i, j);
-                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(i, j);
+                } catch (Exception ex) {}
+
+                NBTTagCompound chunk;
+                try {
+                     chunk = NBTCompressedStreamTools.readNBT(datainputstream);
+                } catch (Exception ex) {
+                    return null;
+                }
+                // Paper end
                 if (oversizedData == null) {
                     return chunk;
                 }
@@ -251,7 +263,13 @@ public class RegionFileCache {
             return null;
         }
 
-        return NBTCompressedStreamTools.a(datainputstream);
+        // Paper start - Handle bad chunks more gracefully
+        try {
+            return NBTCompressedStreamTools.a(datainputstream);
+        } catch (Exception ex) {
+            return null;
+        }
+        // Paper end
     }
 
     @Nullable
-- 
2.21.0