From 9c1542f8979637fcea83b327b5252f2fae8933a1 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Thu, 4 Jun 2020 22:17:00 +0900
Subject: [PATCH] Fix crash when pressing clear button twice

---
 .../Settings/TestSceneKeyBindingPanel.cs      | 45 ++++++++++++++++++-
 osu.Game/Overlays/KeyBinding/KeyBindingRow.cs |  5 ++-
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/osu.Game.Tests/Visual/Settings/TestSceneKeyBindingPanel.cs b/osu.Game.Tests/Visual/Settings/TestSceneKeyBindingPanel.cs
index 745820696a..3d335995ac 100644
--- a/osu.Game.Tests/Visual/Settings/TestSceneKeyBindingPanel.cs
+++ b/osu.Game.Tests/Visual/Settings/TestSceneKeyBindingPanel.cs
@@ -1,13 +1,19 @@
 // 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.Diagnostics;
+using System.Linq;
 using NUnit.Framework;
+using osu.Framework.Testing;
+using osu.Framework.Threading;
 using osu.Game.Overlays;
+using osu.Game.Overlays.KeyBinding;
+using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.Settings
 {
     [TestFixture]
-    public class TestSceneKeyBindingPanel : OsuTestScene
+    public class TestSceneKeyBindingPanel : OsuManualInputManagerTestScene
     {
         private readonly KeyBindingPanel panel;
 
@@ -21,5 +27,42 @@ namespace osu.Game.Tests.Visual.Settings
             base.LoadComplete();
             panel.Show();
         }
+
+        [Test]
+        public void TestClickTwiceOnClearButton()
+        {
+            KeyBindingRow firstRow = null;
+
+            AddStep("click first row", () =>
+            {
+                firstRow = panel.ChildrenOfType<KeyBindingRow>().First();
+                InputManager.MoveMouseTo(firstRow);
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddStep("schedule button clicks", () =>
+            {
+                var clearButton = firstRow.ChildrenOfType<KeyBindingRow.ClearButton>().Single();
+
+                InputManager.MoveMouseTo(clearButton);
+
+                int buttonClicks = 0;
+                ScheduledDelegate clickDelegate = null;
+
+                clickDelegate = Scheduler.AddDelayed(() =>
+                {
+                    InputManager.PressButton(MouseButton.Left);
+                    InputManager.ReleaseButton(MouseButton.Left);
+
+                    if (++buttonClicks == 2)
+                    {
+                        // ReSharper disable once AccessToModifiedClosure
+                        Debug.Assert(clickDelegate != null);
+                        // ReSharper disable once AccessToModifiedClosure
+                        clickDelegate.Cancel();
+                    }
+                }, 0, true);
+            });
+        }
     }
 }
diff --git a/osu.Game/Overlays/KeyBinding/KeyBindingRow.cs b/osu.Game/Overlays/KeyBinding/KeyBindingRow.cs
index 01d5991d3e..eafb4572ca 100644
--- a/osu.Game/Overlays/KeyBinding/KeyBindingRow.cs
+++ b/osu.Game/Overlays/KeyBinding/KeyBindingRow.cs
@@ -274,6 +274,9 @@ namespace osu.Game.Overlays.KeyBinding
 
         private void clear()
         {
+            if (bindTarget == null)
+                return;
+
             bindTarget.UpdateKeyCombination(InputKey.None);
             finalise();
         }
@@ -333,7 +336,7 @@ namespace osu.Game.Overlays.KeyBinding
             }
         }
 
-        private class ClearButton : TriangleButton
+        public class ClearButton : TriangleButton
         {
             public ClearButton()
             {