From 1df6ce4e38946564765dab9227ed093b5f33812f Mon Sep 17 00:00:00 2001
From: Moritz Bender <35152647+Morilli@users.noreply.github.com>
Date: Fri, 25 Nov 2022 11:00:44 +0100
Subject: [PATCH] Fix key release events with modifiers not getting handled
 correctly (#3402)

---
 .../input/InputCoalescerControllers.cs        | 16 ++++++++--
 src/BizHawk.Client.EmuHawk/Input/Input.cs     | 30 -------------------
 2 files changed, 13 insertions(+), 33 deletions(-)

diff --git a/src/BizHawk.Client.Common/input/InputCoalescerControllers.cs b/src/BizHawk.Client.Common/input/InputCoalescerControllers.cs
index 15d2301e02..905ff583a6 100644
--- a/src/BizHawk.Client.Common/input/InputCoalescerControllers.cs
+++ b/src/BizHawk.Client.Common/input/InputCoalescerControllers.cs
@@ -1,7 +1,7 @@
 #nullable enable
 
 using System.Linq;
-
+using BizHawk.Common.StringExtensions;
 using BizHawk.Emulation.Common;
 
 namespace BizHawk.Client.Common
@@ -20,8 +20,11 @@ namespace BizHawk.Client.Common
 			Buttons[button] = state;
 			ProcessSubsets(button, state);
 			if (state) return;
-			// when a button is released, all modified variants of it are released as well
-			foreach (var k in Buttons.Keys.Where(k => k.EndsWith($"+{ie.LogicalButton.Button}")).ToList()) Buttons[k] = false;
+			// when a button or modifier key is released, all modified key variants with it are released as well
+			foreach (var k in Buttons.Keys.Where(k =>
+						k.EndsWith($"+{ie.LogicalButton.Button}") || k.StartsWith($"{ie.LogicalButton.Button}+") || k.Contains($"+{ie.LogicalButton.Button}+"))
+						.ToArray())
+				Buttons[k] = false;
 		}
 	}
 
@@ -29,6 +32,13 @@ namespace BizHawk.Client.Common
 	{
 		protected override void ProcessSubsets(string button, bool state)
 		{
+			// we don't want a release of e.g. "Ctrl+E" to release Ctrl as well
+			if (!state)
+			{
+				Buttons[button.SubstringAfterLast('+')] = state;
+				return;
+			}
+
 			// For controller input, we want Shift+X to register as both Shift and X (for Keyboard controllers)
 			foreach (var s in button.Split('+')) Buttons[s] = state;
 		}
diff --git a/src/BizHawk.Client.EmuHawk/Input/Input.cs b/src/BizHawk.Client.EmuHawk/Input/Input.cs
index 7573586eac..4c9367a8be 100644
--- a/src/BizHawk.Client.EmuHawk/Input/Input.cs
+++ b/src/BizHawk.Client.EmuHawk/Input/Input.cs
@@ -64,7 +64,6 @@ namespace BizHawk.Client.EmuHawk
 			_updateThread.Start();
 		}
 
-		private readonly Dictionary<string, LogicalButton> _modifierState = new Dictionary<string, LogicalButton>();
 		private readonly WorkingDictionary<string, bool> _lastState = new WorkingDictionary<string, bool>();
 		private readonly WorkingDictionary<string, int> _axisValues = new WorkingDictionary<string, int>();
 		private readonly WorkingDictionary<string, float> _axisDeltas = new WorkingDictionary<string, float>();
@@ -129,35 +128,6 @@ namespace BizHawk.Client.EmuHawk
 				};
 			_lastState[button1] = newState;
 
-			// track the pressed events with modifiers that we send so that we can send corresponding unpresses with modifiers
-			// this is an interesting idea, which we may need later, but not yet.
-			// for example, you may see this series of events: press:ctrl+c, release:ctrl, release:c
-			// but you might would rather have press:ctrl+c, release:ctrl+c
-			// this code relates the releases to the original presses.
-			// UPDATE - this is necessary for the frame advance key, which has a special meaning when it gets stuck down
-			// so, i am adding it as of 11-sep-2011
-			if (newState)
-			{
-				_modifierState[button1] = ie.LogicalButton;
-			}
-			else
-			{
-				if (_modifierState.TryGetValue(button1, out var buttonModifierState))
-				{
-					if (buttonModifierState != ie.LogicalButton && !_ignoreEventsNextPoll)
-					{
-						_newEvents.Add(
-							new InputEvent
-							{
-								LogicalButton = buttonModifierState,
-								EventType = InputEventType.Release,
-								Source = source
-							});
-					}
-					_modifierState.Remove(button1);
-				}
-			}
-
 			if (!_ignoreEventsNextPoll)
 			{
 				_newEvents.Add(ie);