Paper/patches/server/Thread-Safe-Vanilla-Command-permission-checking.patch
Octavia Togami 1291aa829a Replace ThreadLocal with ConcurrentHashMap in CommandSourceStack (#6325)
This object is created so often that it likely creates problems with the
ThreadLocalMap because the weak references can't be cleaned up fast
enough. This has manifest as lag seemingly caused by WorldEdit:
https://github.com/EngineHub/WorldEdit/issues/1668
2021-08-21 20:45:40 -07:00

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3.5 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 11 Jul 2020 03:54:28 -0400
Subject: [PATCH] Thread Safe Vanilla Command permission checking
Datapacks check this on load and are built concurrently. This was breaking them badly due
to race conditions.
Plus, .canUse we want to be safe for async anyways.
diff --git a/src/main/java/com/mojang/brigadier/tree/CommandNode.java b/src/main/java/com/mojang/brigadier/tree/CommandNode.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/com/mojang/brigadier/tree/CommandNode.java
+++ b/src/main/java/com/mojang/brigadier/tree/CommandNode.java
@@ -0,0 +0,0 @@ public abstract class CommandNode<S> implements Comparable<CommandNode<S>> {
public synchronized boolean canUse(final S source) {
if (source instanceof CommandSourceStack) {
try {
- ((CommandSourceStack) source).currentCommand = this;
+ ((CommandSourceStack) source).currentCommand.put(Thread.currentThread(), this); // Paper
return this.requirement.test(source);
} finally {
- ((CommandSourceStack) source).currentCommand = null;
+ ((CommandSourceStack) source).currentCommand.remove(Thread.currentThread()); // Paper
}
}
// CraftBukkit end
diff --git a/src/main/java/net/minecraft/commands/CommandSourceStack.java b/src/main/java/net/minecraft/commands/CommandSourceStack.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/commands/CommandSourceStack.java
+++ b/src/main/java/net/minecraft/commands/CommandSourceStack.java
@@ -0,0 +0,0 @@ import com.mojang.brigadier.suggestion.Suggestions;
import com.mojang.brigadier.suggestion.SuggestionsBuilder;
import java.util.Collection;
import java.util.Iterator;
+import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
import java.util.function.BinaryOperator;
import java.util.stream.Stream;
import javax.annotation.Nullable;
@@ -0,0 +0,0 @@ public class CommandSourceStack implements SharedSuggestionProvider, com.destroy
private final ResultConsumer<CommandSourceStack> consumer;
private final EntityAnchorArgument.Anchor anchor;
private final Vec2 rotation;
- public volatile CommandNode currentCommand; // CraftBukkit
+ public Map<Thread, CommandNode> currentCommand = new ConcurrentHashMap<>(); // CraftBukkit // Paper
public CommandSourceStack(CommandSource output, Vec3 pos, Vec2 rot, ServerLevel world, int level, String name, Component displayName, MinecraftServer server, @Nullable Entity entity) {
this(output, pos, rot, world, level, name, displayName, server, entity, false, (commandcontext, flag, j) -> {
@@ -0,0 +0,0 @@ public class CommandSourceStack implements SharedSuggestionProvider, com.destroy
@Override
public boolean hasPermission(int level) {
// CraftBukkit start
- CommandNode currentCommand = this.currentCommand;
+ // Paper start - fix concurrency issue
+ CommandNode currentCommand = this.currentCommand.get(Thread.currentThread());
if (currentCommand != null) {
return this.hasPermission(level, org.bukkit.craftbukkit.command.VanillaCommandWrapper.getPermission(currentCommand));
+ // Paper end
}
// CraftBukkit end