From 142a67e1634fb379e8725d3ad51e5cf4dd9825a6 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Fri, 28 Jan 2022 18:53:28 +0900
Subject: [PATCH 1/2] Fix approach rate not being transferred from OD on older
 beatmaps

---
 osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
index 01ba0fcc9f..07ada8ecc4 100644
--- a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
@@ -311,10 +311,13 @@ namespace osu.Game.Beatmaps.Formats
 
                 case @"OverallDifficulty":
                     difficulty.OverallDifficulty = Parsing.ParseFloat(pair.Value);
+                    if (!hasApproachRate)
+                        difficulty.ApproachRate = difficulty.OverallDifficulty;
                     break;
 
                 case @"ApproachRate":
                     difficulty.ApproachRate = Parsing.ParseFloat(pair.Value);
+                    hasApproachRate = true;
                     break;
 
                 case @"SliderMultiplier":
@@ -432,6 +435,7 @@ namespace osu.Game.Beatmaps.Formats
         private readonly List<ControlPoint> pendingControlPoints = new List<ControlPoint>();
         private readonly HashSet<Type> pendingControlPointTypes = new HashSet<Type>();
         private double pendingControlPointsTime;
+        private bool hasApproachRate;
 
         private void addControlPoint(double time, ControlPoint point, bool timingChange)
         {

From bda3cdc9a773ac76c36470174e13db398e33fd7e Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Fri, 28 Jan 2022 19:28:42 +0900
Subject: [PATCH 2/2] Add tests

---
 .../Formats/LegacyBeatmapDecoderTest.cs       | 42 +++++++++++++++++++
 ...approach-rate-after-overall-difficulty.osu |  3 ++
 ...pproach-rate-before-overall-difficulty.osu |  3 ++
 .../Resources/undefined-approach-rate.osu     |  2 +
 4 files changed, 50 insertions(+)
 create mode 100644 osu.Game.Tests/Resources/approach-rate-after-overall-difficulty.osu
 create mode 100644 osu.Game.Tests/Resources/approach-rate-before-overall-difficulty.osu
 create mode 100644 osu.Game.Tests/Resources/undefined-approach-rate.osu

diff --git a/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs b/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs
index 3a6051ed43..468cb7683c 100644
--- a/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs
+++ b/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs
@@ -821,5 +821,47 @@ namespace osu.Game.Tests.Beatmaps.Formats
                 });
             }
         }
+
+        [Test]
+        public void TestUndefinedApproachRateInheritsOverallDifficulty()
+        {
+            var decoder = new LegacyBeatmapDecoder { ApplyOffsets = false };
+
+            using (var resStream = TestResources.OpenResource("undefined-approach-rate.osu"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var decoded = decoder.Decode(stream);
+                Assert.That(decoded.Difficulty.ApproachRate, Is.EqualTo(1));
+                Assert.That(decoded.Difficulty.OverallDifficulty, Is.EqualTo(1));
+            }
+        }
+
+        [Test]
+        public void TestApproachRateDefinedBeforeOverallDifficulty()
+        {
+            var decoder = new LegacyBeatmapDecoder { ApplyOffsets = false };
+
+            using (var resStream = TestResources.OpenResource("approach-rate-before-overall-difficulty.osu"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var decoded = decoder.Decode(stream);
+                Assert.That(decoded.Difficulty.ApproachRate, Is.EqualTo(9));
+                Assert.That(decoded.Difficulty.OverallDifficulty, Is.EqualTo(1));
+            }
+        }
+
+        [Test]
+        public void TestApproachRateDefinedAfterOverallDifficulty()
+        {
+            var decoder = new LegacyBeatmapDecoder { ApplyOffsets = false };
+
+            using (var resStream = TestResources.OpenResource("approach-rate-after-overall-difficulty.osu"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var decoded = decoder.Decode(stream);
+                Assert.That(decoded.Difficulty.ApproachRate, Is.EqualTo(9));
+                Assert.That(decoded.Difficulty.OverallDifficulty, Is.EqualTo(1));
+            }
+        }
     }
 }
diff --git a/osu.Game.Tests/Resources/approach-rate-after-overall-difficulty.osu b/osu.Game.Tests/Resources/approach-rate-after-overall-difficulty.osu
new file mode 100644
index 0000000000..23732aef8c
--- /dev/null
+++ b/osu.Game.Tests/Resources/approach-rate-after-overall-difficulty.osu
@@ -0,0 +1,3 @@
+[Difficulty]
+OverallDifficulty:1
+ApproachRate:9
\ No newline at end of file
diff --git a/osu.Game.Tests/Resources/approach-rate-before-overall-difficulty.osu b/osu.Game.Tests/Resources/approach-rate-before-overall-difficulty.osu
new file mode 100644
index 0000000000..18885c6624
--- /dev/null
+++ b/osu.Game.Tests/Resources/approach-rate-before-overall-difficulty.osu
@@ -0,0 +1,3 @@
+[Difficulty]
+ApproachRate:9
+OverallDifficulty:1
\ No newline at end of file
diff --git a/osu.Game.Tests/Resources/undefined-approach-rate.osu b/osu.Game.Tests/Resources/undefined-approach-rate.osu
new file mode 100644
index 0000000000..0de24238bf
--- /dev/null
+++ b/osu.Game.Tests/Resources/undefined-approach-rate.osu
@@ -0,0 +1,2 @@
+[Difficulty]
+OverallDifficulty:1
\ No newline at end of file