Ensure chunk neighbor counts do not get desynced

Mojang was not checking that the chunk did not overwrite, or
was successfully removed.

We're seeing odd reports in #1561 that indicates issues around
this are having problems.
This commit is contained in:
Aikar 2018-10-17 22:47:27 -04:00
parent b3b0490651
commit ec2f1e4093
2 changed files with 80 additions and 1 deletions

View file

@ -0,0 +1,52 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 17 Oct 2018 22:31:54 -0400
Subject: [PATCH] Ensure chunk neighbor counts do not get desynced
Mojang was not checking that the chunk did not overwrite, or
was successfully removed.
We're seeing odd reports in #1561 that indicates issues around
this are having problems.
diff --git a/src/main/java/net/minecraft/server/ChunkMap.java b/src/main/java/net/minecraft/server/ChunkMap.java
index 39ac032b0b..1fb0770015 100644
--- a/src/main/java/net/minecraft/server/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/ChunkMap.java
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
chunk.world.timings.syncChunkLoadPostTimer.startTiming(); // Paper
lastChunkByPos = chunk; // Paper
Chunk chunk1 = (Chunk) super.put(i, chunk);
+ if (chunk1 == null) { // Paper - we should never be overwriting chunks
ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i);
for (int j = chunkcoordintpair.x - 1; j <= chunkcoordintpair.x + 1; ++j) {
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
chunk.setNeighborLoaded(x, z);
}
}
+ // Paper start
+ } } else {
+ a.error("Overwrote existing chunk! (" + chunk.world.getWorld().getName() + ":" + chunk.locX+"," + chunk.locZ + ")", new IllegalStateException());
}
+ // Paper end
// Paper start - if this is a spare chunk (not part of any players view distance), go ahead and queue it for unload.
if (!((WorldServer)chunk.world).getPlayerChunkMap().isChunkInUse(chunk.locX, chunk.locZ)) {
if (chunk.world.paperConfig.delayChunkUnloadsBy > 0) {
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
public Chunk a(long i) {
Chunk chunk = (Chunk) super.remove(i);
+ if (chunk != null) { // Paper - don't decrement if we didn't remove anything
ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i);
for (int j = chunkcoordintpair.x - 1; j <= chunkcoordintpair.x + 1; ++j) {
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
}
// Paper start
+ } // close if (chunk != null)
if (lastChunkByPos != null && i == lastChunkByPos.chunkKey) {
lastChunkByPos = null;
}
--

View file

@ -9,7 +9,7 @@ getChunkAt is called for the same chunk multiple times in a row, often from getT
Optimize this look up by using a Last Access cache.
diff --git a/src/main/java/net/minecraft/server/ChunkMap.java b/src/main/java/net/minecraft/server/ChunkMap.java
index 4b8b77710b..df967ff07d 100644
index 4b8b77710b..71ddaf591e 100644
--- a/src/main/java/net/minecraft/server/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/ChunkMap.java
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
@ -20,6 +20,33 @@ index 4b8b77710b..df967ff07d 100644
Chunk chunk1 = (Chunk) super.put(i, chunk);
ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i);
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
for (int k = chunkcoordintpair.z - 1; k <= chunkcoordintpair.z + 1; ++k) {
if (j != chunkcoordintpair.x || k != chunkcoordintpair.z) {
long l = ChunkCoordIntPair.a(j, k);
- Chunk chunk2 = (Chunk) this.get(l);
+ Chunk chunk2 = (Chunk) super.get(l); // Paper - use super to avoid polluting last access cache
if (chunk2 != null) {
chunk.H();
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
continue;
}
- Chunk neighbor = this.get(ChunkCoordIntPair.a(chunkcoordintpair.x + x, chunkcoordintpair.z + z));
+ Chunk neighbor = super.get(ChunkCoordIntPair.a(chunkcoordintpair.x + x, chunkcoordintpair.z + z)); // Paper - use super to avoid polluting last access cache
if (neighbor != null) {
neighbor.setNeighborLoaded(-x, -z);
chunk.setNeighborLoaded(x, z);
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
for (int j = chunkcoordintpair.x - 1; j <= chunkcoordintpair.x + 1; ++j) {
for (int k = chunkcoordintpair.z - 1; k <= chunkcoordintpair.z + 1; ++k) {
if (j != chunkcoordintpair.x || k != chunkcoordintpair.z) {
- Chunk chunk1 = (Chunk) this.get(ChunkCoordIntPair.a(j, k));
+ Chunk chunk1 = (Chunk) super.get(ChunkCoordIntPair.a(j, k)); // Paper - use super to avoid polluting last access cache
if (chunk1 != null) {
chunk1.I();
@@ -0,0 +0,0 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
}
}