Paper/patches/server/0381-Thread-Safe-Vanilla-Command-permission-checking.patch
Spottedleaf 8c5b837e05 Rework async chunk api implementation
Firstly, the old methods all routed to the CompletableFuture method.
However, the CF method could not guarantee that if the caller
was off-main that the future would be "completed" on-main. Since
the callback methods used the CF one, this meant that the callback
methods did not guarantee that the callbacks were to be called on
the main thread.

Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb)
so that the methods with the callback are guaranteed to invoke
the callback on the main thread. The CF behavior remains unchanged;
it may still appear to complete on main if invoked off-main.

Secondly, remove the scheduleOnMain invocation in the async
chunk completion. This unnecessarily delays the callback
by 1 tick.

Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which
will load chunks within an area. This method is provided as a helper
as keeping all chunks loaded within an area can be complicated to
implement for plugins (due to the lacking ticket API), and is
already implemented internally anyways.

Fourthly, remove the ticket addition that occured with getChunkAt
and getChunkAtAsync. The ticket addition may delay the unloading
of the chunk unnecessarily. It also fixes a very rare timing bug
where the future/callback would be completed after the chunk
unloads.
2024-11-18 23:00:59 -08:00

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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 14ccd0c8f721e9be7dca8a5dcb8ef95b5cd82731..1f4963bf4681a771130abc1da179819626ecfc1f 100644
--- a/src/main/java/com/mojang/brigadier/tree/CommandNode.java
+++ b/src/main/java/com/mojang/brigadier/tree/CommandNode.java
@@ -75,10 +75,10 @@ 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 - Thread Safe Vanilla Command permission checking
return this.requirement.test(source);
} finally {
- ((CommandSourceStack) source).currentCommand = null;
+ ((CommandSourceStack) source).currentCommand.remove(Thread.currentThread()); // Paper - Thread Safe Vanilla Command permission checking
}
}
// CraftBukkit end
diff --git a/src/main/java/net/minecraft/commands/CommandSourceStack.java b/src/main/java/net/minecraft/commands/CommandSourceStack.java
index 5316f148f3f9128690f019d544e462b042d8d797..f31c5d665678c3163ed4469f8e9d395b890c1bbe 100644
--- a/src/main/java/net/minecraft/commands/CommandSourceStack.java
+++ b/src/main/java/net/minecraft/commands/CommandSourceStack.java
@@ -66,7 +66,7 @@ public class CommandSourceStack implements ExecutionCommandSource<CommandSourceS
private final Vec2 rotation;
private final CommandSigningContext signingContext;
private final TaskChainer chatMessageChainer;
- public volatile CommandNode currentCommand; // CraftBukkit
+ public java.util.Map<Thread, CommandNode> currentCommand = new java.util.concurrent.ConcurrentHashMap<>(); // CraftBukkit // Paper - Thread Safe Vanilla Command permission checking
public boolean bypassSelectorPermissions = false; // Paper - add bypass for selector permissions
public CommandSourceStack(CommandSource output, Vec3 pos, Vec2 rot, ServerLevel world, int level, String name, Component displayName, MinecraftServer server, @Nullable Entity entity) {
@@ -195,9 +195,11 @@ public class CommandSourceStack implements ExecutionCommandSource<CommandSourceS
@Override
public boolean hasPermission(int level) {
// CraftBukkit start
- CommandNode currentCommand = this.currentCommand;
+ // Paper start - Thread Safe Vanilla Command permission checking
+ CommandNode currentCommand = this.currentCommand.get(Thread.currentThread());
if (currentCommand != null) {
return this.hasPermission(level, org.bukkit.craftbukkit.command.VanillaCommandWrapper.getPermission(currentCommand));
+ // Paper end - Thread Safe Vanilla Command permission checking
}
// CraftBukkit end