Do note propagate SurroundingTextChanged back to iOS

Author: kerams

src/iOS/Avalonia.iOS/TextInputResponder.cs

@@ -90,6 +90,7 @@ public TextInputResponder(AvaloniaView view, TextInputMethodClient client)
         private int _inSurroundingTextUpdateEvent;
         private readonly UITextPosition _beginningOfDocument = new AvaloniaTextPosition(0);
         private readonly UITextInputStringTokenizer _tokenizer;
+        private bool _isInUpdate;
 
         public TextInputMethodClient? Client => _client;
 
@@ -142,15 +143,15 @@ public override UITextInputMode TextInputMode
         private void SurroundingTextChanged(object? sender, EventArgs e)
         {
             Logger.TryGet(LogEventLevel.Debug, ImeLog)?.Log(null, "SurroundingTextChanged");
-            if (WeakInputDelegate == null)
+            if (WeakInputDelegate == null || _isInUpdate)
                 return;
             _inSurroundingTextUpdateEvent++;
             try
             {
                 objc_msgSend(WeakInputDelegate.Handle.Handle, TextWillChange, Handle.Handle);
                 objc_msgSend(WeakInputDelegate.Handle.Handle, TextDidChange, Handle.Handle);
-                objc_msgSend(WeakInputDelegate.Handle.Handle, SelectionWillChange, this.Handle.Handle);
-                objc_msgSend(WeakInputDelegate.Handle.Handle, SelectionDidChange, this.Handle.Handle);
+                objc_msgSend(WeakInputDelegate.Handle.Handle, SelectionWillChange, Handle.Handle);
+                objc_msgSend(WeakInputDelegate.Handle.Handle, SelectionDidChange, Handle.Handle);
             }
             finally
             {
@@ -180,6 +181,7 @@ private void TextInput(string text)
 
         void IUIKeyInput.InsertText(string text)
         {
+            _isInUpdate = true;
             Logger.TryGet(LogEventLevel.Debug, ImeLog)?.Log(null, "IUIKeyInput.InsertText {text}", text);
 
             if (text == "\n")
@@ -203,9 +205,15 @@ void IUIKeyInput.InsertText(string text)
             }
 
             TextInput(text);
+            _isInUpdate = false;
         }
 
-        void IUIKeyInput.DeleteBackward() => KeyPress(Key.Back, PhysicalKey.Backspace, "\b");
+        void IUIKeyInput.DeleteBackward()
+        {
+            _isInUpdate = true;
+            KeyPress(Key.Back, PhysicalKey.Backspace, "\b");
+            _isInUpdate = false;
+        }
 
         bool IUIKeyInput.HasText => true;