PaperMC/patches/server/0397-Do-not-let-the-server-load-chunks-from-newer-version.patch
Bjarne Koll c5a10665b8
Remove wall-time / unused skip tick protection (#11412)
Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.
2024-09-19 16:36:07 +02:00

41 lines
2.6 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Zach Brown <zach@zachbr.io>
Date: Tue, 23 Jul 2019 20:44:47 -0500
Subject: [PATCH] Do not let the server load chunks from newer versions
If the server attempts to load a chunk generated by a newer version of
the game, immediately stop the server to prevent data corruption.
You can override this functionality at your own peril.
diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java b/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
index 0dd6f1bce4913cb84ba21a20df5573bab3a64645..5e1a68e3a920aab10a459b9b54f6abd59e7855e0 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/ChunkSerializer.java
@@ -86,6 +86,10 @@ public class ChunkSerializer {
public static final String BLOCK_LIGHT_TAG = "BlockLight";
public static final String SKY_LIGHT_TAG = "SkyLight";
+ // Paper start - Do not let the server load chunks from newer versions
+ private static final int CURRENT_DATA_VERSION = net.minecraft.SharedConstants.getCurrentVersion().getDataVersion().getVersion();
+ private static final boolean JUST_CORRUPT_IT = Boolean.getBoolean("Paper.ignoreWorldDataVersion");
+ // Paper end - Do not let the server load chunks from newer versions
public ChunkSerializer() {}
// Paper start - guard against serializing mismatching coordinates
@@ -102,6 +106,15 @@ public class ChunkSerializer {
// Paper end - guard against serializing mismatching coordinates
public static ProtoChunk read(ServerLevel world, PoiManager poiStorage, RegionStorageInfo key, ChunkPos chunkPos, CompoundTag nbt) {
+ // Paper start - Do not let the server load chunks from newer versions
+ if (nbt.contains("DataVersion", net.minecraft.nbt.Tag.TAG_ANY_NUMERIC)) {
+ final int dataVersion = nbt.getInt("DataVersion");
+ if (!JUST_CORRUPT_IT && dataVersion > CURRENT_DATA_VERSION) {
+ new RuntimeException("Server attempted to load chunk saved with newer version of minecraft! " + dataVersion + " > " + CURRENT_DATA_VERSION).printStackTrace();
+ System.exit(1);
+ }
+ }
+ // Paper end - Do not let the server load chunks from newer versions
ChunkPos chunkcoordintpair1 = new ChunkPos(nbt.getInt("xPos"), nbt.getInt("zPos")); // Paper - guard against serializing mismatching coordinates; diff on change, see ChunkSerializer#getChunkCoordinate
if (!Objects.equals(chunkPos, chunkcoordintpair1)) {