SelectableRegion does not merge child semantics nodes (#104659)

Author: chunhtai

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

@@ -780,6 +780,7 @@ class _SelectableRegionState extends State<SelectableRegion> with TextSelectionD
         child: Actions(
           actions: _actions,
           child: Focus(
+            includeSemantics: false,
             focusNode: widget.focusNode,
             child: SelectionContainer(
               registrar: this,

packages/flutter/test/widgets/selectable_region_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../widgets/clipboard_utils.dart';
+import 'semantics_tester.dart';
 
 Offset textOffsetToPosition(RenderParagraph paragraph, int offset) {
   const Rect caret = Rect.fromLTWH(0.0, 0.0, 2.0, 20.0);
@@ -34,7 +35,7 @@ void main() {
     TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, null);
   });
 
-  group('SelectionArea', () {
+  group('SelectableRegion', () {
     testWidgets('mouse selection sends correct events', (WidgetTester tester) async {
       final UniqueKey spy = UniqueKey();
       await tester.pumpWidget(
@@ -94,6 +95,81 @@ void main() {
       );
     });
 
+    testWidgets('does not merge semantics node of the children', (WidgetTester tester) async {
+      final SemanticsTester semantics = SemanticsTester(tester);
+      await tester.pumpWidget(
+        MaterialApp(
+          home: SelectableRegion(
+            focusNode: FocusNode(),
+            selectionControls: materialTextSelectionControls,
+            child: Scaffold(
+              body: Center(
+                child: Column(
+                  mainAxisSize: MainAxisSize.min,
+                  children: <Widget>[
+                    const Text('Line one'),
+                    const Text('Line two'),
+                    ElevatedButton(
+                      onPressed: () {},
+                      child: const Text('Button'),
+                    )
+                  ],
+                ),
+              ),
+            ),
+          ),
+        ),
+      );
+
+      expect(
+        semantics,
+        hasSemantics(
+          TestSemantics.root(
+            children: <TestSemantics>[
+              TestSemantics(
+                textDirection: TextDirection.ltr,
+                children: <TestSemantics>[
+                  TestSemantics(
+                    children: <TestSemantics>[
+                      TestSemantics(
+                        flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
+                        children: <TestSemantics>[
+                          TestSemantics(
+                            label: 'Line one',
+                            textDirection: TextDirection.ltr,
+                          ),
+                          TestSemantics(
+                            label: 'Line two',
+                            textDirection: TextDirection.ltr,
+                          ),
+                          TestSemantics(
+                            flags: <SemanticsFlag>[
+                              SemanticsFlag.isButton,
+                              SemanticsFlag.hasEnabledState,
+                              SemanticsFlag.isEnabled,
+                              SemanticsFlag.isFocusable
+                            ],
+                            actions: <SemanticsAction>[SemanticsAction.tap],
+                            label: 'Button',
+                            textDirection: TextDirection.ltr,
+                          ),
+                        ],
+                      ),
+                    ],
+                  ),
+                ],
+              ),
+            ],
+          ),
+          ignoreRect: true,
+          ignoreTransform: true,
+          ignoreId: true,
+        ),
+      );
+
+      semantics.dispose();
+    });
+
     testWidgets('mouse selection always cancels previous selection', (WidgetTester tester) async {
       final UniqueKey spy = UniqueKey();
       await tester.pumpWidget(