Centralise TrackManager.AddItem logic to avoid duplicate adds

osu.Game/OsuGameBase.cs

@@ -134,11 +134,18 @@ namespace osu.Game
             });
 
             Beatmap.ValueChanged += b =>
+            {
+                // compare to last baetmap as sometimes the two may share a track representation (optimisation, see WorkingBeatmap.TransferTo)
+                if (lastBeatmap?.Track != b.Track)
                 {
                     // this disposal is done to stop the audio track.
                     // it may not be exactly what we want for cases beatmaps are reused, as it will
                     // trigger a fresh load of contained resources.
                     lastBeatmap?.Dispose();
+
+                    Audio.Track.AddItem(b.Track);
+                }
+
                 lastBeatmap = b;
             };
 

osu.Game/Overlays/Music/PlaylistOverlay.cs

@@ -3,9 +3,7 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using osu.Framework.Allocation;
-using osu.Framework.Audio.Track;
 using osu.Framework.Configuration;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
@@ -15,7 +13,6 @@ using osu.Game.Database;
 using osu.Game.Graphics;
 using OpenTK;
 using OpenTK.Graphics;
-using osu.Framework.Extensions;
 using osu.Framework.Input;
 using osu.Framework.Graphics.Shapes;
 
@@ -30,7 +27,6 @@ namespace osu.Game.Overlays.Music
         private FilterControl filter;
         private PlaylistList list;
 
-        private TrackManager trackManager;
         private BeatmapDatabase beatmaps;
 
         private readonly Bindable<WorkingBeatmap> beatmapBacking = new Bindable<WorkingBeatmap>();
@@ -43,7 +39,6 @@ namespace osu.Game.Overlays.Music
         {
             this.inputManager = inputManager;
             this.beatmaps = beatmaps;
-            trackManager = game.Audio.Track;
 
             Children = new Drawable[]
             {
@@ -154,13 +149,7 @@ namespace osu.Game.Overlays.Music
         private void playSpecified(BeatmapInfo info)
         {
             beatmapBacking.Value = beatmaps.GetWorkingBeatmap(info, beatmapBacking);
-
+            beatmapBacking.Value.Track.Start();
-            Task.Run(() =>
-            {
-                var track = beatmapBacking.Value.Track;
-                trackManager.AddItem(track);
-                track.Start();
-            }).ContinueWith(task => Schedule(task.ThrowIfFaulted), TaskContinuationOptions.OnlyOnFaulted);
         }
     }
 

osu.Game/Screens/Menu/Intro.cs

@@ -72,8 +72,6 @@ namespace osu.Game.Screens.Menu
             menuVoice = config.GetBindable<bool>(OsuSetting.MenuVoice);
             menuMusic = config.GetBindable<bool>(OsuSetting.MenuMusic);
 
-            var trackManager = audio.Track;
-
             BeatmapSetInfo setInfo = null;
 
             if (!menuMusic)
@@ -106,7 +104,6 @@ namespace osu.Game.Screens.Menu
             Beatmap.Value = beatmaps.GetWorkingBeatmap(setInfo.Beatmaps[0]);
 
             track = Beatmap.Value.Track;
-            trackManager.AddItem(track);
 
             welcome = audio.Sample.Get(@"welcome");
             seeya = audio.Sample.Get(@"seeya");

osu.Game/Screens/Play/Player.cs

@@ -119,10 +119,7 @@ namespace osu.Game.Screens.Play
             Track track = Beatmap.Value.Track;
 
             if (track != null)
-            {
-                audio.Track.AddItem(track);
                 adjustableSourceClock = track;
-            }
 
             adjustableSourceClock = (IAdjustableClock)track ?? new StopwatchClock();
 

osu.Game/Screens/Select/SongSelect.cs

@@ -32,7 +32,6 @@ namespace osu.Game.Screens.Select
         protected override BackgroundScreen CreateBackground() => new BackgroundScreenBeatmap();
 
         private readonly BeatmapCarousel carousel;
-        private TrackManager trackManager;
         private DialogOverlay dialogOverlay;
 
         private static readonly Vector2 wedged_container_size = new Vector2(0.5f, 245);
@@ -174,7 +173,6 @@ namespace osu.Game.Screens.Select
             database.BeatmapSetAdded += onBeatmapSetAdded;
             database.BeatmapSetRemoved += onBeatmapSetRemoved;
 
-            trackManager = audio.Track;
             dialogOverlay = dialog;
 
             sampleChangeDifficulty = audio.Sample.Get(@"SongSelect/select-difficulty");
@@ -358,11 +356,12 @@ namespace osu.Game.Screens.Select
         {
             Track track = Beatmap.Value.Track;
 
-            trackManager.AddItem(track);
+            if (!track.IsRunning)
-
+            {
                 if (preview) track.Seek(Beatmap.Value.Metadata.PreviewTime);
                 track.Start();
             }
+        }
 
         private void removeBeatmapSet(BeatmapSetInfo beatmapSet)
         {