From 9a24346a008ed8c730bea94adb9271324c5a79a7 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 25 Sep 2020 23:29:40 +0900
Subject: [PATCH] Fix HP drain edgecase potentially causing insta-fails

---
 .../TestSceneDrainingHealthProcessor.cs       | 39 +++++++++++++++++++
 .../Scoring/DrainingHealthProcessor.cs        |  2 +-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/osu.Game.Tests/Gameplay/TestSceneDrainingHealthProcessor.cs b/osu.Game.Tests/Gameplay/TestSceneDrainingHealthProcessor.cs
index 460ad1b898..4876d051aa 100644
--- a/osu.Game.Tests/Gameplay/TestSceneDrainingHealthProcessor.cs
+++ b/osu.Game.Tests/Gameplay/TestSceneDrainingHealthProcessor.cs
@@ -1,15 +1,18 @@
 // 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.Threading;
 using NUnit.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Utils;
 using osu.Framework.Testing;
 using osu.Framework.Timing;
 using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Beatmaps.Timing;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Tests.Visual;
 
@@ -175,6 +178,24 @@ namespace osu.Game.Tests.Gameplay
             assertHealthNotEqualTo(0);
         }
 
+        [Test]
+        public void TestSingleLongObjectDoesNotDrain()
+        {
+            var beatmap = new Beatmap
+            {
+                HitObjects = { new JudgeableLongHitObject() }
+            };
+
+            beatmap.HitObjects[0].ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
+
+            createProcessor(beatmap);
+            setTime(0);
+            assertHealthEqualTo(1);
+
+            setTime(5000);
+            assertHealthEqualTo(1);
+        }
+
         private Beatmap createBeatmap(double startTime, double endTime, params BreakPeriod[] breaks)
         {
             var beatmap = new Beatmap
@@ -235,5 +256,23 @@ namespace osu.Game.Tests.Gameplay
                 }
             }
         }
+
+        private class JudgeableLongHitObject : JudgeableHitObject, IHasDuration
+        {
+            public double EndTime => StartTime + Duration;
+            public double Duration { get; set; } = 5000;
+
+            public JudgeableLongHitObject()
+                : base(false)
+            {
+            }
+
+            protected override void CreateNestedHitObjects(CancellationToken cancellationToken)
+            {
+                base.CreateNestedHitObjects(cancellationToken);
+
+                AddNested(new JudgeableHitObject());
+            }
+        }
     }
 }
diff --git a/osu.Game/Rulesets/Scoring/DrainingHealthProcessor.cs b/osu.Game/Rulesets/Scoring/DrainingHealthProcessor.cs
index 130907b242..ba9bbb055f 100644
--- a/osu.Game/Rulesets/Scoring/DrainingHealthProcessor.cs
+++ b/osu.Game/Rulesets/Scoring/DrainingHealthProcessor.cs
@@ -133,7 +133,7 @@ namespace osu.Game.Rulesets.Scoring
 
         private double computeDrainRate()
         {
-            if (healthIncreases.Count == 0)
+            if (healthIncreases.Count <= 1)
                 return 0;
 
             int adjustment = 1;