From 46483622149904c9240f6f6e53ba4ef283edb07d Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Wed, 29 Jul 2020 11:30:25 +0900
Subject: [PATCH] Safeguard against potential finalise-before-initialised

---
 osu.Game/Beatmaps/BeatmapDifficultyManager.cs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/osu.Game/Beatmaps/BeatmapDifficultyManager.cs b/osu.Game/Beatmaps/BeatmapDifficultyManager.cs
index 58b96b08b0..b80b4e45ed 100644
--- a/osu.Game/Beatmaps/BeatmapDifficultyManager.cs
+++ b/osu.Game/Beatmaps/BeatmapDifficultyManager.cs
@@ -136,10 +136,13 @@ namespace osu.Game.Beatmaps
             trackedUpdateCancellationSource?.Cancel();
             trackedUpdateCancellationSource = null;
 
-            foreach (var c in linkedCancellationSources)
-                c.Dispose();
+            if (linkedCancellationSources != null)
+            {
+                foreach (var c in linkedCancellationSources)
+                    c.Dispose();
 
-            linkedCancellationSources.Clear();
+                linkedCancellationSources.Clear();
+            }
         }
 
         /// <summary>
@@ -239,7 +242,7 @@ namespace osu.Game.Beatmaps
             base.Dispose(isDisposing);
 
             cancelTrackedBindableUpdate();
-            updateScheduler.Dispose();
+            updateScheduler?.Dispose();
         }
 
         private readonly struct DifficultyCacheLookup : IEquatable<DifficultyCacheLookup>