From 9813e46e66b540628479406b39515de3a83c3ccc Mon Sep 17 00:00:00 2001
From: Valentine <21033866+BoomEaro@users.noreply.github.com>
Date: Sun, 6 Oct 2024 10:55:12 +0300
Subject: [PATCH] #3746, #3666: Fix potential race conditions when connecting
 to multiple servers at the same time

---
 proxy/src/main/java/net/md_5/bungee/ServerConnector.java | 5 ++++-
 proxy/src/main/java/net/md_5/bungee/UserConnection.java  | 9 +++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/proxy/src/main/java/net/md_5/bungee/ServerConnector.java b/proxy/src/main/java/net/md_5/bungee/ServerConnector.java
index 82832865..90c5237c 100644
--- a/proxy/src/main/java/net/md_5/bungee/ServerConnector.java
+++ b/proxy/src/main/java/net/md_5/bungee/ServerConnector.java
@@ -361,7 +361,10 @@ public class ServerConnector extends PacketHandler
             if ( user.getServer() != null )
             {
                 // Begin config mode
-                user.unsafe().sendPacket( new StartConfiguration() );
+                if ( user.getCh().getEncodeProtocol() != Protocol.CONFIGURATION )
+                {
+                    user.unsafe().sendPacket( new StartConfiguration() );
+                }
             } else
             {
                 LoginResult loginProfile = user.getPendingConnection().getLoginProfile();
diff --git a/proxy/src/main/java/net/md_5/bungee/UserConnection.java b/proxy/src/main/java/net/md_5/bungee/UserConnection.java
index 54842ca0..2359e864 100644
--- a/proxy/src/main/java/net/md_5/bungee/UserConnection.java
+++ b/proxy/src/main/java/net/md_5/bungee/UserConnection.java
@@ -306,6 +306,11 @@ public final class UserConnection implements ProxiedPlayer
     {
         Preconditions.checkNotNull( request, "request" );
 
+        ch.getHandle().eventLoop().execute( () -> connect0( request ) );
+    }
+
+    private void connect0(final ServerConnectRequest request)
+    {
         final Callback<ServerConnectRequest.Result> callback = request.getCallback();
         ServerConnectEvent event = new ServerConnectEvent( this, request.getTarget(), request.getReason(), request );
         if ( bungee.getPluginManager().callEvent( event ).isCancelled() )
@@ -315,10 +320,6 @@ public final class UserConnection implements ProxiedPlayer
                 callback.done( ServerConnectRequest.Result.EVENT_CANCEL, null );
             }
 
-            if ( getServer() == null && !ch.isClosing() )
-            {
-                throw new IllegalStateException( "Cancelled ServerConnectEvent with no server or disconnect." );
-            }
             return;
         }