From 2fe25f8acf3567ad1869942eb20c6bc068b44387 Mon Sep 17 00:00:00 2001
From: Deadpikle <mbabienco@southern.edu>
Date: Tue, 8 Jun 2021 18:48:12 -0400
Subject: [PATCH] Fix equality for UndoRedoState

In UndoRedoHelper, the .Equals call in Snapshot() did not call Equals(UndoRedoState other). It called the default Equals(object obj) implementation. This could throw of the undo redo snapshotting. Fix that by overriding Equals(object obj).
---
 src/Avalonia.Controls/TextBox.cs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index dad2401921..edd268a86a 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -157,6 +157,13 @@ namespace Avalonia.Controls
             }
 
             public bool Equals(UndoRedoState other) => ReferenceEquals(Text, other.Text) || Equals(Text, other.Text);
+
+            public override bool Equals(object obj)
+            {
+                if (ReferenceEquals(null, obj)) return false;
+                if (obj.GetType() != GetType()) return false;
+                return Equals((UndoRedoState)obj);
+            }
         }
 
         private string _text;