From ee7e2b0854a8096dd55c1e3472b8964311df2897 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 10 Apr 2020 13:29:46 +0900
Subject: [PATCH 1/2] Fix editor beatmap potentially not updating hitobjects

---
 osu.Game/Screens/Edit/EditorBeatmap.cs | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/osu.Game/Screens/Edit/EditorBeatmap.cs b/osu.Game/Screens/Edit/EditorBeatmap.cs
index 7f04a7a58d..efffde54b3 100644
--- a/osu.Game/Screens/Edit/EditorBeatmap.cs
+++ b/osu.Game/Screens/Edit/EditorBeatmap.cs
@@ -63,6 +63,7 @@ namespace osu.Game.Screens.Edit
                 trackStartTime(obj);
         }
 
+        private readonly HashSet<HitObject> pendingUpdates = new HashSet<HitObject>();
         private ScheduledDelegate scheduledUpdate;
 
         /// <summary>
@@ -74,15 +75,27 @@ namespace osu.Game.Screens.Edit
         private void updateHitObject([CanBeNull] HitObject hitObject, bool silent)
         {
             scheduledUpdate?.Cancel();
-            scheduledUpdate = Scheduler.AddDelayed(() =>
+
+            if (hitObject != null)
+                pendingUpdates.Add(hitObject);
+
+            scheduledUpdate = Schedule(() =>
             {
                 beatmapProcessor?.PreProcess();
-                hitObject?.ApplyDefaults(ControlPointInfo, BeatmapInfo.BaseDifficulty);
+
+                foreach (var obj in pendingUpdates)
+                    obj.ApplyDefaults(ControlPointInfo, BeatmapInfo.BaseDifficulty);
+
                 beatmapProcessor?.PostProcess();
 
                 if (!silent)
-                    HitObjectUpdated?.Invoke(hitObject);
-            }, 0);
+                {
+                    foreach (var obj in pendingUpdates)
+                        HitObjectUpdated?.Invoke(obj);
+                }
+
+                pendingUpdates.Clear();
+            });
         }
 
         public BeatmapInfo BeatmapInfo

From 41caa378565d807853dd53ec6b0727d60139bd33 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 10 Apr 2020 13:29:49 +0900
Subject: [PATCH 2/2] Add tests

---
 .../Beatmaps/TestSceneEditorBeatmap.cs        | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/osu.Game.Tests/Beatmaps/TestSceneEditorBeatmap.cs b/osu.Game.Tests/Beatmaps/TestSceneEditorBeatmap.cs
index d367d9f88b..2d4587341d 100644
--- a/osu.Game.Tests/Beatmaps/TestSceneEditorBeatmap.cs
+++ b/osu.Game.Tests/Beatmaps/TestSceneEditorBeatmap.cs
@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Collections.Generic;
 using System.Linq;
 using Microsoft.EntityFrameworkCore.Internal;
 using NUnit.Framework;
@@ -162,5 +163,69 @@ namespace osu.Game.Tests.Beatmaps
             Assert.That(editorBeatmap.HitObjects.Count(h => h == hitCircle), Is.EqualTo(1));
             Assert.That(editorBeatmap.HitObjects.IndexOf(hitCircle), Is.EqualTo(1));
         }
+
+        /// <summary>
+        /// Tests that multiple hitobjects are updated simultaneously.
+        /// </summary>
+        [Test]
+        public void TestMultipleHitObjectUpdate()
+        {
+            var updatedObjects = new List<HitObject>();
+            var allHitObjects = new List<HitObject>();
+            EditorBeatmap editorBeatmap = null;
+
+            AddStep("add beatmap", () =>
+            {
+                updatedObjects.Clear();
+
+                Child = editorBeatmap = new EditorBeatmap(new OsuBeatmap());
+
+                for (int i = 0; i < 10; i++)
+                {
+                    var h = new HitCircle();
+                    editorBeatmap.Add(h);
+                    allHitObjects.Add(h);
+                }
+            });
+
+            AddStep("change all start times", () =>
+            {
+                editorBeatmap.HitObjectUpdated += h => updatedObjects.Add(h);
+
+                for (int i = 0; i < 10; i++)
+                    allHitObjects[i].StartTime += 10;
+            });
+
+            // Distinct ensures that all hitobjects have been updated once, debounce is tested below.
+            AddAssert("all hitobjects updated", () => updatedObjects.Distinct().Count() == 10);
+        }
+
+        /// <summary>
+        /// Tests that hitobject updates are debounced when they happen too soon.
+        /// </summary>
+        [Test]
+        public void TestDebouncedUpdate()
+        {
+            var updatedObjects = new List<HitObject>();
+            EditorBeatmap editorBeatmap = null;
+
+            AddStep("add beatmap", () =>
+            {
+                updatedObjects.Clear();
+
+                Child = editorBeatmap = new EditorBeatmap(new OsuBeatmap());
+                editorBeatmap.Add(new HitCircle());
+            });
+
+            AddStep("change start time twice", () =>
+            {
+                editorBeatmap.HitObjectUpdated += h => updatedObjects.Add(h);
+
+                editorBeatmap.HitObjects[0].StartTime = 10;
+                editorBeatmap.HitObjects[0].StartTime = 20;
+            });
+
+            AddAssert("only updated once", () => updatedObjects.Count == 1);
+        }
     }
 }