Merge pull request #11137 from peppy/fix-player-load-stuck-at-empty-screen

osu.Game/Screens/Play/PlayerLoader.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -71,8 +72,9 @@ namespace osu.Game.Screens.Play
         }
 
         private bool readyForPush =>
+            !playerConsumed
             // don't push unless the player is completely loaded
-            player?.LoadState == LoadState.Ready
+            && player?.LoadState == LoadState.Ready
             // don't push if the user is hovering one of the panes, unless they are idle.
             && (IsHovered || idleTracker.IsIdle.Value)
             // don't push if the user is dragging a slider or otherwise.
@@ -84,6 +86,11 @@ namespace osu.Game.Screens.Play
 
         private Player player;
 
+        /// <summary>
+        /// Whether the curent player instance has been consumed via <see cref="consumePlayer"/>.
+        /// </summary>
+        private bool playerConsumed;
+
         private LogoTrackingContainer content;
 
         private bool hideOverlays;
@@ -179,7 +186,10 @@ namespace osu.Game.Screens.Play
             contentIn();
 
             MetadataInfo.Delay(750).FadeIn(500);
-            this.Delay(1800).Schedule(pushWhenLoaded);
+
+            // after an initial delay, start the debounced load check.
+            // this will continue to execute even after resuming back on restart.
+            Scheduler.Add(new ScheduledDelegate(pushWhenLoaded, 1800, 0));
 
             showMuteWarningIfNeeded();
         }
@@ -188,17 +198,18 @@ namespace osu.Game.Screens.Play
         {
             base.OnResuming(last);
 
-            contentIn();
+            // prepare for a retry.
+            player = null;
+            playerConsumed = false;
+            cancelLoad();
 
-            this.Delay(400).Schedule(pushWhenLoaded);
+            contentIn();
         }
 
         public override void OnSuspending(IScreen next)
         {
             base.OnSuspending(next);
 
-            cancelLoad();
-
             BackgroundBrightnessReduction = false;
 
             // we're moving to player, so a period of silence is upcoming.
@@ -274,6 +285,14 @@ namespace osu.Game.Screens.Play
             }
         }
 
+        private Player consumePlayer()
+        {
+            Debug.Assert(!playerConsumed);
+
+            playerConsumed = true;
+            return player;
+        }
+
         private void prepareNewPlayer()
         {
             if (!this.IsCurrentScreen())
@@ -315,8 +334,6 @@ namespace osu.Game.Screens.Play
         {
             if (!this.IsCurrentScreen()) return;
 
-            try
-            {
             if (!readyForPush)
             {
                 // as the pushDebounce below has a delay, we need to keep checking and cancel a future debounce
@@ -325,11 +342,16 @@ namespace osu.Game.Screens.Play
                 return;
             }
 
+            // if a push has already been scheduled, no further action is required.
+            // this value is reset via cancelLoad() to allow a second usage of the same PlayerLoader screen.
             if (scheduledPushPlayer != null)
                 return;
 
             scheduledPushPlayer = Scheduler.AddDelayed(() =>
             {
+                // ensure that once we have reached this "point of no return", readyForPush will be false for all future checks (until a new player instance is prepared).
+                var consumedPlayer = consumePlayer();
+
                 contentOut();
 
                 TransformSequence<PlayerLoader> pushSequence = this.Delay(250);
@@ -362,18 +384,13 @@ namespace osu.Game.Screens.Play
                     // Note that this may change if the player we load requested a re-run.
                     ValidForResume = false;
 
-                        if (player.LoadedBeatmapSuccessfully)
+                    if (consumedPlayer.LoadedBeatmapSuccessfully)
-                            this.Push(player);
+                        this.Push(consumedPlayer);
                     else
                         this.Exit();
                 });
             }, 500);
         }
-            finally
-            {
-                Schedule(pushWhenLoaded);
-            }
-        }
 
         private void cancelLoad()
         {
@@ -390,7 +407,7 @@ namespace osu.Game.Screens.Play
             if (isDisposing)
             {
                 // if the player never got pushed, we should explicitly dispose it.
-                DisposalTask = LoadTask?.ContinueWith(_ => player.Dispose());
+                DisposalTask = LoadTask?.ContinueWith(_ => player?.Dispose());
             }
         }