Make TextFormFieldState.didChange change text fields value (#54481)

packages/flutter/lib/src/material/text_form_field.dart

@@ -309,6 +309,14 @@ class _TextFormFieldState extends FormFieldState<String> {
     super.dispose();
   }
 
+  @override
+  void didChange(String value) {
+    super.didChange(value);
+
+    if (_effectiveController.text != value)
+      _effectiveController.text = value;
+  }
+
   @override
   void reset() {
     super.reset();

packages/flutter/test/material/text_form_field_test.dart

@@ -331,4 +331,50 @@ void main() {
     await tester.pump(const Duration(milliseconds: 300));
     expect(tapCount, 3);
   });
+
+  // Regression test for https://github.com/flutter/flutter/issues/54472.
+  testWidgets('reset resets the text fields value to the initialValue', (WidgetTester tester) async {
+    await tester.pumpWidget(
+        MaterialApp(
+          home: Material(
+            child: Center(
+              child: TextFormField(
+                initialValue: 'initialValue',
+              ),
+            ),
+          ),
+        )
+    );
+
+    await tester.enterText(find.byType(TextFormField), 'changedValue');
+
+    final FormFieldState<String> state = tester.state<FormFieldState<String>>(find.byType(TextFormField));
+    state.reset();
+
+    expect(find.text('changedValue'), findsNothing);
+    expect(find.text('initialValue'), findsOneWidget);
+  });
+
+  // Regression test for https://github.com/flutter/flutter/issues/54472.
+  testWidgets('didChange changes text fields value', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextFormField(
+              initialValue: 'initialValue',
+            ),
+          ),
+        ),
+      )
+    );
+
+    expect(find.text('initialValue'), findsOneWidget);
+
+    final FormFieldState<String> state = tester.state<FormFieldState<String>>(find.byType(TextFormField));
+    state.didChange('changedValue');
+
+    expect(find.text('initialValue'), findsNothing);
+    expect(find.text('changedValue'), findsOneWidget);
+  });
 }