Reland "Track lastKnownRemoteTextEditingValue separately from received data" (#50307)

packages/flutter/lib/src/widgets/editable_text.dart

@@ -1222,7 +1222,13 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
 
   // TextInputClient implementation:
 
-  TextEditingValue _lastKnownRemoteTextEditingValue;
+  // _lastFormattedUnmodifiedTextEditingValue tracks the last value
+  // that the formatter ran on and is used to prevent double-formatting.
+  TextEditingValue _lastFormattedUnmodifiedTextEditingValue;
+  // _receivedRemoteTextEditingValue is the direct value last passed in
+  // updateEditingValue. This value does not get updated with the formatted
+  // version.
+  TextEditingValue _receivedRemoteTextEditingValue;
 
   @override
   TextEditingValue get currentTextEditingValue => _value;
@@ -1234,6 +1240,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     if (widget.readOnly) {
       return;
     }
+    _receivedRemoteTextEditingValue = value;
     if (value.text != _value.text) {
       hideToolbar();
       _showCaretOnScreen();
@@ -1242,7 +1249,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         _obscureLatestCharIndex = _value.selection.baseOffset;
       }
     }
-    _lastKnownRemoteTextEditingValue = value;
+
     _formatAndSetValue(value);
 
     // To keep the cursor from blinking while typing, we want to restart the
@@ -1269,7 +1276,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         break;
       default:
         // Finalize editing, but don't give up focus because this keyboard
-        //  action does not imply the user is done inputting information.
+        // action does not imply the user is done inputting information.
         _finalizeEditing(false);
         break;
     }
@@ -1369,9 +1376,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     if (!_hasInputConnection)
       return;
     final TextEditingValue localValue = _value;
-    if (localValue == _lastKnownRemoteTextEditingValue)
+    if (localValue == _receivedRemoteTextEditingValue)
       return;
-    _lastKnownRemoteTextEditingValue = localValue;
     _textInputConnection.setEditingState(localValue);
   }
 
@@ -1432,7 +1438,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     }
     if (!_hasInputConnection) {
       final TextEditingValue localValue = _value;
-      _lastKnownRemoteTextEditingValue = localValue;
+      _lastFormattedUnmodifiedTextEditingValue = localValue;
       _textInputConnection = TextInput.attach(
         this,
         TextInputConfiguration(
@@ -1472,7 +1478,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     if (_hasInputConnection) {
       _textInputConnection.close();
       _textInputConnection = null;
-      _lastKnownRemoteTextEditingValue = null;
+      _lastFormattedUnmodifiedTextEditingValue = null;
+      _receivedRemoteTextEditingValue = null;
     }
   }
 
@@ -1490,7 +1497,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     if (_hasInputConnection) {
       _textInputConnection.connectionClosedReceived();
       _textInputConnection = null;
-      _lastKnownRemoteTextEditingValue = null;
+      _lastFormattedUnmodifiedTextEditingValue = null;
+      _receivedRemoteTextEditingValue = null;
       _finalizeEditing(true);
     }
   }
@@ -1634,8 +1642,11 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   void _formatAndSetValue(TextEditingValue value) {
+    // Check if the new value is the same as the current local value, or is the same
+    // as the post-formatting value of the previous pass.
     final bool textChanged = _value?.text != value?.text;
-    if (textChanged && widget.inputFormatters != null && widget.inputFormatters.isNotEmpty) {
+    final bool isRepeat = value?.text == _lastFormattedUnmodifiedTextEditingValue?.text;
+    if (textChanged && !isRepeat && widget.inputFormatters != null && widget.inputFormatters.isNotEmpty) {
       for (final TextInputFormatter formatter in widget.inputFormatters)
         value = formatter.formatEditUpdate(_value, value);
       _value = value;
@@ -1645,6 +1656,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     }
     if (textChanged && widget.onChanged != null)
       widget.onChanged(value.text);
+    _lastFormattedUnmodifiedTextEditingValue = _receivedRemoteTextEditingValue;
   }
 
   void _onCursorColorTick() {

packages/flutter/test/widgets/editable_text_test.dart

@@ -4209,6 +4209,114 @@ void main() {
     final dynamic exception = tester.takeException();
     expect(exception, isNull);
   });
+
+  testWidgets('updateEditingValue filters multiple calls from formatter', (WidgetTester tester) async {
+    final MockTextFormatter formatter = MockTextFormatter();
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(devicePixelRatio: 1.0),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: FocusScope(
+            node: focusScopeNode,
+            autofocus: true,
+            child: EditableText(
+              backgroundCursorColor: Colors.grey,
+              controller: controller,
+              focusNode: focusNode,
+              maxLines: 1, // Sets text keyboard implicitly.
+              style: textStyle,
+              cursorColor: cursorColor,
+              inputFormatters: <TextInputFormatter>[formatter],
+            ),
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.byType(EditableText));
+    await tester.showKeyboard(find.byType(EditableText));
+    controller.text = '';
+    await tester.idle();
+
+    final EditableTextState state =
+        tester.state<EditableTextState>(find.byType(EditableText));
+    expect(tester.testTextInput.editingState['text'], equals(''));
+    expect(state.wantKeepAlive, true);
+
+    state.updateEditingValue(const TextEditingValue(text: ''));
+    state.updateEditingValue(const TextEditingValue(text: 'a'));
+    state.updateEditingValue(const TextEditingValue(text: 'aa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaaa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaaaaaa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaaaaaaaa'));
+    state.updateEditingValue(const TextEditingValue(text: 'aaaaaaaaa')); // Skipped
+
+    const List<String> referenceLog = <String>[
+      '[1]: , a',
+      '[1]: normal aa',
+      '[2]: aa, aaa',
+      '[2]: normal aaaa',
+      '[3]: aaaa, aa',
+      '[3]: deleting a',
+      '[4]: a, aaa',
+      '[4]: normal aaaaaaaa',
+      '[5]: aaaaaaaa, aaaa',
+      '[5]: deleting aaa',
+      '[6]: aaa, aa',
+      '[6]: deleting aaaa',
+      '[7]: aaaa, aaaaaaa',
+      '[7]: normal aaaaaaaaaaaaaa',
+      '[8]: aaaaaaaaaaaaaa, aa',
+      '[8]: deleting aaaaaa',
+      '[9]: aaaaaa, aaaaaaaaa',
+      '[9]: normal aaaaaaaaaaaaaaaaaa',
+    ];
+
+    expect(formatter.log, referenceLog);
+  });
+}
+
+class MockTextFormatter extends TextInputFormatter {
+  MockTextFormatter() : _counter = 0, log = <String>[];
+
+  int _counter;
+  List<String> log;
+
+  @override
+  TextEditingValue formatEditUpdate(
+    TextEditingValue oldValue,
+    TextEditingValue newValue,
+  ) {
+    _counter++;
+    log.add('[$_counter]: ${oldValue.text}, ${newValue.text}');
+    TextEditingValue finalValue;
+    if (newValue.text.length < oldValue.text.length) {
+      finalValue = _handleTextDeletion(oldValue, newValue);
+    } else {
+      finalValue = _formatText(newValue);
+    }
+    return finalValue;
+  }
+
+
+  TextEditingValue _handleTextDeletion(
+      TextEditingValue oldValue, TextEditingValue newValue) {
+    final String result = 'a' * (_counter - 2);
+    log.add('[$_counter]: deleting $result');
+    return TextEditingValue(text: result);
+  }
+
+  TextEditingValue _formatText(TextEditingValue value) {
+    final String result = 'a' * _counter * 2;
+    log.add('[$_counter]: normal $result');
+    return TextEditingValue(text: result);
+  }
 }
 
 class MockTextSelectionControls extends Mock implements TextSelectionControls {