From 839f5a75705f92cb77dfb75392ecf748a7f955d9 Mon Sep 17 00:00:00 2001
From: Salman Ahmed <frenzibyte@gmail.com>
Date: Sun, 3 Jan 2021 18:36:37 +0300
Subject: [PATCH] Ensure clients don't blow up when given user isn't in room

---
 osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
index c1818de87a..799b66020c 100644
--- a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
+++ b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
@@ -320,10 +320,13 @@ namespace osu.Game.Online.Multiplayer
 
             Scheduler.Add(() =>
             {
-                if (Room == null)
+                var user = Room?.Users.SingleOrDefault(u => u.UserID == userId);
+
+                // we don't care whether the room doesn't exist or user isn't in joined room, just return in that point.
+                if (user == null)
                     return;
 
-                Room.Users.Single(u => u.UserID == userId).BeatmapAvailability = beatmapAvailability;
+                user.BeatmapAvailability = beatmapAvailability;
 
                 RoomUpdated?.Invoke();
             }, false);