PaperMC/paper-server/patches/sources/com/mojang/brigadier/tree/CommandNode.java.patch

--- a/com/mojang/brigadier/tree/CommandNode.java
+++ b/com/mojang/brigadier/tree/CommandNode.java
@@ -3,6 +3,7 @@
 
 package com.mojang.brigadier.tree;
 
+// CHECKSTYLE:OFF
 import com.mojang.brigadier.AmbiguityConsumer;
 import com.mojang.brigadier.Command;
 import com.mojang.brigadier.RedirectModifier;
@@ -22,6 +23,7 @@
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Predicate;
+import net.minecraft.commands.CommandSourceStack;
 
 public abstract class CommandNode<S> implements Comparable<CommandNode<S>> {
     private final Map<String, CommandNode<S>> children = new LinkedHashMap<>();
@@ -32,6 +34,14 @@
     private final RedirectModifier<S> modifier;
     private final boolean forks;
     private Command<S> command;
+    public CommandNode<CommandSourceStack> clientNode; // Paper - Brigadier API
+    // CraftBukkit start
+    public void removeCommand(String name) {
+        this.children.remove(name);
+        this.literals.remove(name);
+        this.arguments.remove(name);
+    }
+    // CraftBukkit end
 
     protected CommandNode(final Command<S> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks) {
         this.command = command;
@@ -61,7 +71,17 @@
         return this.modifier;
     }
 
-    public boolean canUse(final S source) {
+    // CraftBukkit start
+    public synchronized boolean canUse(final S source) {
+        if (source instanceof CommandSourceStack) {
+            try {
+                ((CommandSourceStack) source).currentCommand.put(Thread.currentThread(), this); // Paper - Thread Safe Vanilla Command permission checking
+                return this.requirement.test(source);
+            } finally {
+                ((CommandSourceStack) source).currentCommand.remove(Thread.currentThread()); // Paper - Thread Safe Vanilla Command permission checking
+            }
+        }
+        // CraftBukkit end
         return this.requirement.test(source);
     }