From a350802158d7413c9bdb37319b47d92efb17a1be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Thu, 10 Sep 2020 19:21:16 +0200
Subject: [PATCH] Fix wrong mono streak length handling in corner case

---
 .../Difficulty/Skills/Colour.cs               |  7 ++++++-
 .../NonVisual/LimitedCapacityQueueTest.cs     | 21 +++++++++++++++++++
 .../Difficulty/Utils/LimitedCapacityQueue.cs  |  9 ++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
index ecd74f54ed..32421ee00a 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
@@ -45,7 +45,12 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills
             // hits spaced more than a second apart are also exempt from colour strain.
             if (!(current.LastObject is Hit && current.BaseObject is Hit && current.DeltaTime < 1000))
             {
-                previousHitType = null;
+                monoHistory.Clear();
+
+                var currentHit = current.BaseObject as Hit;
+                currentMonoLength = currentHit != null ? 1 : 0;
+                previousHitType = currentHit?.Type;
+
                 return 0.0;
             }
 
diff --git a/osu.Game.Tests/NonVisual/LimitedCapacityQueueTest.cs b/osu.Game.Tests/NonVisual/LimitedCapacityQueueTest.cs
index 52463dd7eb..a04415bc7f 100644
--- a/osu.Game.Tests/NonVisual/LimitedCapacityQueueTest.cs
+++ b/osu.Game.Tests/NonVisual/LimitedCapacityQueueTest.cs
@@ -94,5 +94,26 @@ namespace osu.Game.Tests.NonVisual
 
             Assert.Throws<InvalidOperationException>(() => queue.Dequeue());
         }
+
+        [Test]
+        public void TestClearQueue()
+        {
+            queue.Enqueue(3);
+            queue.Enqueue(5);
+            Assert.AreEqual(2, queue.Count);
+
+            queue.Clear();
+            Assert.AreEqual(0, queue.Count);
+            Assert.Throws<ArgumentOutOfRangeException>(() => _ = queue[0]);
+
+            queue.Enqueue(7);
+            Assert.AreEqual(1, queue.Count);
+            Assert.AreEqual(7, queue[0]);
+            Assert.Throws<ArgumentOutOfRangeException>(() => _ = queue[1]);
+
+            queue.Enqueue(9);
+            Assert.AreEqual(2, queue.Count);
+            Assert.AreEqual(9, queue[1]);
+        }
     }
 }
diff --git a/osu.Game/Rulesets/Difficulty/Utils/LimitedCapacityQueue.cs b/osu.Game/Rulesets/Difficulty/Utils/LimitedCapacityQueue.cs
index 0f014e8a8c..bc0eb8af88 100644
--- a/osu.Game/Rulesets/Difficulty/Utils/LimitedCapacityQueue.cs
+++ b/osu.Game/Rulesets/Difficulty/Utils/LimitedCapacityQueue.cs
@@ -40,8 +40,17 @@ namespace osu.Game.Rulesets.Difficulty.Utils
 
             this.capacity = capacity;
             array = new T[capacity];
+            Clear();
+        }
+
+        /// <summary>
+        /// Removes all elements from the <see cref="LimitedCapacityQueue{T}"/>.
+        /// </summary>
+        public void Clear()
+        {
             start = 0;
             end = -1;
+            Count = 0;
         }
 
         /// <summary>