From d5ed218488aac139909012bb0343a69edf357421 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Wed, 27 Sep 2017 11:07:43 +0800
Subject: [PATCH] Fix timeline sizes being updated potentially before the track
 has a length

---
 .../Timelines/Summary/Parts/TimelinePart.cs   | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Screens/Edit/Components/Timelines/Summary/Parts/TimelinePart.cs b/osu.Game/Screens/Edit/Components/Timelines/Summary/Parts/TimelinePart.cs
index 8071aa9c59..75651640d5 100644
--- a/osu.Game/Screens/Edit/Components/Timelines/Summary/Parts/TimelinePart.cs
+++ b/osu.Game/Screens/Edit/Components/Timelines/Summary/Parts/TimelinePart.cs
@@ -25,11 +25,31 @@ namespace osu.Game.Screens.Edit.Components.Timelines.Summary.Parts
 
             Beatmap.ValueChanged += b =>
             {
-                timeline.RelativeChildSize = new Vector2((float)Math.Max(1, b.Track.Length), 1);
+                updateRelativeChildSize();
                 LoadBeatmap(b);
             };
         }
 
+        private void updateRelativeChildSize()
+        {
+            if (!Beatmap.Value.TrackLoaded)
+            {
+                timeline.RelativeChildSize = Vector2.One;
+                return;
+            }
+
+            var track = Beatmap.Value.Track;
+
+            if (!track.IsLoaded)
+            {
+                // the track may not be loaded completely (only has a length once it is).
+                Schedule(updateRelativeChildSize);
+                return;
+            }
+
+            timeline.RelativeChildSize = new Vector2((float)Math.Max(1, track.Length), 1);
+        }
+
         protected void Add(Drawable visualisation) => timeline.Add(visualisation);
 
         protected virtual void LoadBeatmap(WorkingBeatmap beatmap)