PaperMC/patches/server/0725-Warn-on-plugins-accessing-faraway-chunks.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

96 lines
5.2 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
Date: Fri, 29 Jul 2022 12:35:19 -0400
Subject: [PATCH] Warn on plugins accessing faraway chunks
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index b4111bcc6a676dc42b233761aa667708669c2ab8..cc92d2e8b77c75da1d8b850c3bc251e8ac221c24 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -339,7 +339,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
}
private static boolean isInWorldBoundsHorizontal(BlockPos pos) {
- return pos.getX() >= -30000000 && pos.getZ() >= -30000000 && pos.getX() < 30000000 && pos.getZ() < 30000000;
+ return pos.getX() >= -30000000 && pos.getZ() >= -30000000 && pos.getX() < 30000000 && pos.getZ() < 30000000; // Diff on change warnUnsafeChunk()
}
private static boolean isOutsideSpawnableHeight(int y) {
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index a1912eb5fd26898d7e9848ffb2052fce2fa10868..cb28a7504e809a8b1e8ab6e34e14e414c542055f 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -305,9 +305,24 @@ public class CraftWorld extends CraftRegionAccessor implements World {
public boolean setSpawnLocation(int x, int y, int z) {
return this.setSpawnLocation(x, y, z, 0.0F);
}
+ // Paper start
+ private static void warnUnsafeChunk(String reason, int x, int z) {
+ // if any chunk coord is outside of 30 million blocks
+ if (x > 1875000 || z > 1875000 || x < -1875000 || z < -1875000) {
+ Plugin plugin = io.papermc.paper.util.StackWalkerUtil.getFirstPluginCaller();
+ if (plugin != null) {
+ plugin.getLogger().warning("Plugin is %s at (%s, %s), this might cause issues.".formatted(reason, x, z));
+ }
+ if (net.minecraft.server.MinecraftServer.getServer().isDebugging()) {
+ io.papermc.paper.util.TraceUtil.dumpTraceForThread("Dangerous chunk retrieval");
+ }
+ }
+ }
+ // Paper end
@Override
public Chunk getChunkAt(int x, int z) {
+ warnUnsafeChunk("getting a faraway chunk", x, z); // Paper
// Paper start - add ticket to hold chunk for a little while longer if plugin accesses it
net.minecraft.world.level.chunk.LevelChunk chunk = this.world.getChunkSource().getChunkAtIfLoadedImmediately(x, z);
if (chunk == null) {
@@ -413,6 +428,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
if (!unloadChunk0(x, z, false)) {
return false;
}
+ warnUnsafeChunk("regenerating a faraway chunk", x, z); // Paper
final long chunkKey = ChunkCoordIntPair.pair(x, z);
world.getChunkProvider().unloadQueue.remove(chunkKey);
@@ -486,6 +502,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public boolean loadChunk(int x, int z, boolean generate) {
org.spigotmc.AsyncCatcher.catchOp("chunk load"); // Spigot
+ warnUnsafeChunk("loading a faraway chunk", x, z); // Paper
ChunkAccess chunk = this.world.getChunkSource().getChunk(x, z, generate || isChunkGenerated(x, z) ? ChunkStatus.FULL : ChunkStatus.EMPTY, true); // Paper
// If generate = false, but the chunk already exists, we will get this back.
@@ -518,6 +535,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public boolean addPluginChunkTicket(int x, int z, Plugin plugin) {
+ warnUnsafeChunk("adding a faraway chunk ticket", x, z); // Paper
Preconditions.checkArgument(plugin != null, "null plugin");
Preconditions.checkArgument(plugin.isEnabled(), "plugin is not enabled");
@@ -618,6 +636,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public void setChunkForceLoaded(int x, int z, boolean forced) {
+ warnUnsafeChunk("forceloading a faraway chunk", x, z); // Paper
this.getHandle().setChunkForced(x, z, forced);
}
@@ -946,6 +965,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public int getHighestBlockYAt(int x, int z, org.bukkit.HeightMap heightMap) {
+ warnUnsafeChunk("getting a faraway chunk", x >> 4, z >> 4); // Paper
// Transient load for this tick
return this.world.getChunk(x >> 4, z >> 4).getHeight(CraftHeightMap.toNMS(heightMap), x, z);
}
@@ -2343,6 +2363,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
// Spigot end
// Paper start
public java.util.concurrent.CompletableFuture<Chunk> getChunkAtAsync(int x, int z, boolean gen, boolean urgent) {
+ warnUnsafeChunk("getting a faraway chunk async", x, z); // Paper
if (Bukkit.isPrimaryThread()) {
net.minecraft.world.level.chunk.LevelChunk immediate = this.world.getChunkSource().getChunkAtIfLoadedImmediately(x, z);
if (immediate != null) {