Fix focus when popping pages (#49714)

Fixes the focus handling when popping pages so that when multiple pages are popped, the focus doesn't try to focus the interstitial pages.

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

@@ -677,10 +677,15 @@ class _ModalScopeState<T> extends State<_ModalScope<T>> {
     super.dispose();
   }
 
+  bool get _shouldIgnoreFocusRequest {
+    return widget.route.animation?.status == AnimationStatus.reverse ||
+      (widget.route.navigator?.userGestureInProgress ?? false);
+  }
+
   // This should be called to wrap any changes to route.isCurrent, route.canPop,
   // and route.offstage.
   void _routeSetState(VoidCallback fn) {
-    if (widget.route.isCurrent) {
+    if (widget.route.isCurrent && !_shouldIgnoreFocusRequest) {
       widget.route.navigator.focusScopeNode.setFirstFocus(focusScopeNode);
     }
     setState(fn);
@@ -713,8 +718,7 @@ class _ModalScopeState<T> extends State<_ModalScope<T>> {
                     AnimatedBuilder(
                       animation: widget.route.navigator?.userGestureInProgressNotifier ?? ValueNotifier<bool>(false),
                       builder: (BuildContext context, Widget child) {
-                        final bool ignoreEvents = widget.route.animation?.status == AnimationStatus.reverse ||
-                            (widget.route.navigator?.userGestureInProgress ?? false);
+                        final bool ignoreEvents = _shouldIgnoreFocusRequest;
                         focusScopeNode.canRequestFocus = !ignoreEvents;
                         return IgnorePointer(
                           ignoring: ignoreEvents,

packages/flutter/test/widgets/routes_test.dart

@@ -1159,6 +1159,52 @@ void main() {
       modalBarrierAnimation = tester.widget<AnimatedModalBarrier>(animatedModalBarrier).color;
       expect(modalBarrierAnimation.value, Colors.black);
     });
+
+    testWidgets('focus traverse correct when pop mutiple page simultaneously', (WidgetTester tester) async {
+      // Regression test: https://github.com/flutter/flutter/issues/48903
+      final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
+      await tester.pumpWidget(MaterialApp(
+        navigatorKey: navigatorKey,
+        home: const Text('dummy1'),
+      ));
+      final Element textOnPageOne = tester.element(find.text('dummy1'));
+      final FocusScopeNode focusNodeOnPageOne = FocusScope.of(textOnPageOne);
+      expect(focusNodeOnPageOne.hasFocus, isTrue);
+
+      // Pushes one page.
+      navigatorKey.currentState.push<void>(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('dummy2'),
+        )
+      );
+      await tester.pumpAndSettle();
+
+      final Element textOnPageTwo = tester.element(find.text('dummy2'));
+      final FocusScopeNode focusNodeOnPageTwo = FocusScope.of(textOnPageTwo);
+      // The focus should be on second page.
+      expect(focusNodeOnPageOne.hasFocus, isFalse);
+      expect(focusNodeOnPageTwo.hasFocus, isTrue);
+
+      // Pushes another page.
+      navigatorKey.currentState.push<void>(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('dummy3'),
+        )
+      );
+      await tester.pumpAndSettle();
+      final Element textOnPageThree = tester.element(find.text('dummy3'));
+      final FocusScopeNode focusNodeOnPageThree = FocusScope.of(textOnPageThree);
+      // The focus should be on third page.
+      expect(focusNodeOnPageOne.hasFocus, isFalse);
+      expect(focusNodeOnPageTwo.hasFocus, isFalse);
+      expect(focusNodeOnPageThree.hasFocus, isTrue);
+
+      // Pops two pages simultaneously.
+      navigatorKey.currentState.popUntil((Route<void> route) => route.isFirst);
+      await tester.pumpAndSettle();
+      // It should refocus page one after pops.
+      expect(focusNodeOnPageOne.hasFocus, isTrue);
+    });
   });
 }