[Cupertino] Exclude border for last action item in `CupertinoContextMenu` (#92481)

packages/flutter/lib/src/cupertino/context_menu.dart

@@ -9,10 +9,17 @@ import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
+import 'colors.dart';
+
 // The scale of the child at the time that the CupertinoContextMenu opens.
 // This value was eyeballed from a physical device running iOS 13.1.2.
 const double _kOpenScale = 1.1;
 
+const Color _borderColor = CupertinoDynamicColor.withBrightness(
+  color: Color(0xFFA9A9AF),
+  darkColor: Color(0xFF57585A),
+);
+
 typedef _DismissCallback = void Function(
   BuildContext context,
   double scale,
@@ -1151,8 +1158,8 @@ class _ContextMenuSheet extends StatelessWidget {
 
   // Get the children, whose order depends on orientation and
   // contextMenuLocation.
-  List<Widget> get children {
-    final Flexible menu = Flexible(
+  List<Widget> getChildren(BuildContext context) {
+    final Widget menu = Flexible(
       fit: FlexFit.tight,
       flex: 2,
       child: IntrinsicHeight(
@@ -1160,7 +1167,22 @@ class _ContextMenuSheet extends StatelessWidget {
           borderRadius: const BorderRadius.all(Radius.circular(13.0)),
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.stretch,
-            children: actions,
+            children: <Widget>[
+              actions.first,
+              for (Widget action in actions.skip(1))
+                DecoratedBox(
+                  decoration: BoxDecoration(
+                    border: Border(
+                      top: BorderSide(
+                        color: CupertinoDynamicColor.resolve(_borderColor, context),
+                        width: 0.5,
+                      )
+                    ),
+                  ),
+                  position: DecorationPosition.foreground,
+                  child: action,
+                ),
+            ],
           ),
         ),
       ),
@@ -1195,7 +1217,7 @@ class _ContextMenuSheet extends StatelessWidget {
   Widget build(BuildContext context) {
     return Row(
       crossAxisAlignment: CrossAxisAlignment.start,
-      children: children,
+      children: getChildren(context),
     );
   }
 }

packages/flutter/lib/src/cupertino/context_menu_action.dart

@@ -115,9 +115,6 @@ class _CupertinoContextMenuActionState extends State<CupertinoContextMenuAction>
           child: Container(
             decoration: BoxDecoration(
               color: _isPressed ? _kBackgroundColorPressed : _kBackgroundColor,
-              border: const Border(
-                bottom: BorderSide(color: _kBackgroundColorPressed),
-              ),
             ),
             padding: const EdgeInsets.symmetric(
               vertical: 16.0,

packages/flutter/test/cupertino/context_menu_test.dart

@@ -9,7 +9,6 @@ void main() {
   final TestWidgetsFlutterBinding binding =
     TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding;
   const double _kOpenScale = 1.1;
-
   Widget _getChild() {
     return Container(
       width: 300.0,
@@ -66,6 +65,13 @@ void main() {
     );
   }
 
+  Finder _findStaticChildDecoration(WidgetTester tester) {
+    return find.descendant(
+      of: _findStatic(),
+      matching: find.byType(DecoratedBox),
+    );
+  }
+
   group('CupertinoContextMenu before and during opening', () {
     testWidgets('An unopened CupertinoContextMenu renders child in the same place as without', (WidgetTester tester) async {
       // Measure the child in the scene with no CupertinoContextMenu.
@@ -190,6 +196,65 @@ void main() {
   });
 
   group('CupertinoContextMenu when open', () {
+    testWidgets('Last action does not have border', (WidgetTester tester) async {
+      final Widget child  = _getChild();
+      await tester.pumpWidget(CupertinoApp(
+        home: CupertinoPageScaffold(
+          child: Center(
+            child: CupertinoContextMenu(
+              actions: const <CupertinoContextMenuAction>[
+                CupertinoContextMenuAction(
+                  child: Text('CupertinoContextMenuAction One'),
+                ),
+              ],
+              child: child,
+            ),
+          ),
+        ),
+      ));
+
+      // Open the CupertinoContextMenu
+      final TestGesture firstGesture = await tester.startGesture(tester.getCenter(find.byWidget(child)));
+      await tester.pumpAndSettle();
+      await firstGesture.up();
+      await tester.pumpAndSettle();
+      expect(_findStatic(), findsOneWidget);
+
+      expect(_findStaticChildDecoration(tester), findsNWidgets(1));
+
+      // Close the CupertinoContextMenu.
+      await tester.tapAt(const Offset(1.0, 1.0));
+      await tester.pumpAndSettle();
+      expect(_findStatic(), findsNothing);
+
+      await tester.pumpWidget(CupertinoApp(
+        home: CupertinoPageScaffold(
+          child: Center(
+            child: CupertinoContextMenu(
+              actions: const <CupertinoContextMenuAction>[
+                CupertinoContextMenuAction(
+                  child: Text('CupertinoContextMenuAction One'),
+                ),
+                CupertinoContextMenuAction(
+                  child: Text('CupertinoContextMenuAction Two'),
+                ),
+              ],
+              child: child,
+            ),
+          ),
+        ),
+      ));
+
+      // Open the CupertinoContextMenu
+      final TestGesture secondGesture = await tester.startGesture(tester.getCenter(find.byWidget(child)));
+      await tester.pumpAndSettle();
+      await secondGesture.up();
+      await tester.pumpAndSettle();
+      expect(_findStatic(), findsOneWidget);
+
+      expect(_findStaticChildDecoration(tester), findsNWidgets(3));
+    });
+
     testWidgets('Can close CupertinoContextMenu by background tap', (WidgetTester tester) async {
       final Widget child = _getChild();
       await tester.pumpWidget(_getContextMenu(child: child));