From 07ef2bbab97ec883bdad515ba4db1bff65dfcc81 Mon Sep 17 00:00:00 2001
From: Rick <rickw320@hotmail.com>
Date: Sun, 8 Dec 2024 22:43:09 +0100
Subject: [PATCH] Fix incorrect command serialization by creating new Command
 (#11671)

Fixes #11649 - As noted in the issue, when CommandNodes are serialized
they are used as the key in a Map. Their equals()/hashcode() should only    match if they are equal nodes (name & command), but due to the erasure of the command field pre-serialization, nodes with different commands can be mapped onto the same value. This causes the client to interpret both nodes as the same, causing suggestions where they should not.

This is fixed by creating a different no-op command for the
erasure, instead of them holding the same lambda.
---
 ...mmand-serialization-by-creating-new-.patch | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 patches/server/1074-Fix-incorrect-command-serialization-by-creating-new-.patch

diff --git a/patches/server/1074-Fix-incorrect-command-serialization-by-creating-new-.patch b/patches/server/1074-Fix-incorrect-command-serialization-by-creating-new-.patch
new file mode 100644
index 0000000000..20311c23aa
--- /dev/null
+++ b/patches/server/1074-Fix-incorrect-command-serialization-by-creating-new-.patch
@@ -0,0 +1,33 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Rick <rickw320@hotmail.com>
+Date: Tue, 26 Nov 2024 20:45:52 +0100
+Subject: [PATCH] Fix incorrect command serialization by creating new Command
+
+Fixes #11649 - As noted in the issue, when CommandNodes are serialized
+they are used as the key in a Map. Their equals()/hashcode() should only
+match if they are equal nodes (name & command), but due to the erasure of the command field pre-serialization, nodes with different commands can be mapped onto the same value. This causes the client to interpret both nodes as the same, causing suggestions where they should not.
+
+This is fixed by creating a different no-op command for the
+erasure, instead of them holding the same lambda.
+
+diff --git a/src/main/java/net/minecraft/commands/Commands.java b/src/main/java/net/minecraft/commands/Commands.java
+index 64bf4444ffba25cb40743a32267aa790ad1738f9..517cb238ec280aadd1fc54bcb675ed386e798eaf 100644
+--- a/src/main/java/net/minecraft/commands/Commands.java
++++ b/src/main/java/net/minecraft/commands/Commands.java
+@@ -587,9 +587,14 @@ public class Commands {
+                     return true;
+                 });
+                 if (argumentbuilder.getCommand() != null) {
+-                    argumentbuilder.executes((commandcontext) -> {
+-                        return 0;
++                    // Paper start - fix suggestions due to falsely equal nodes
++                    argumentbuilder.executes(new com.mojang.brigadier.Command<io.papermc.paper.command.brigadier.CommandSourceStack>() {
++                        @Override
++                        public int run(com.mojang.brigadier.context.CommandContext<io.papermc.paper.command.brigadier.CommandSourceStack> commandContext) throws CommandSyntaxException {
++                            return 0;
++                        }
+                     });
++                    // Paper end
+                 }
+ 
+                 if (argumentbuilder instanceof RequiredArgumentBuilder) {