Revert "Do not rebuild Routes when a new opaque Route is pushed on top (#48900)" (#49366)

This reverts commit 8eecdbe8.

packages/flutter/lib/src/rendering/stack.dart

@@ -425,8 +425,7 @@ class RenderStack extends RenderBox
     }
   }
 
-  /// Helper function for calculating the intrinsics metrics of a Stack.
-  static double getIntrinsicDimension(RenderBox firstChild, double mainChildSizeGetter(RenderBox child)) {
+  double _getIntrinsicDimension(double mainChildSizeGetter(RenderBox child)) {
     double extent = 0.0;
     RenderBox child = firstChild;
     while (child != null) {
@@ -441,22 +440,22 @@ class RenderStack extends RenderBox
 
   @override
   double computeMinIntrinsicWidth(double height) {
-    return getIntrinsicDimension(firstChild, (RenderBox child) => child.getMinIntrinsicWidth(height));
+    return _getIntrinsicDimension((RenderBox child) => child.getMinIntrinsicWidth(height));
   }
 
   @override
   double computeMaxIntrinsicWidth(double height) {
-    return getIntrinsicDimension(firstChild, (RenderBox child) => child.getMaxIntrinsicWidth(height));
+    return _getIntrinsicDimension((RenderBox child) => child.getMaxIntrinsicWidth(height));
   }
 
   @override
   double computeMinIntrinsicHeight(double width) {
-    return getIntrinsicDimension(firstChild, (RenderBox child) => child.getMinIntrinsicHeight(width));
+    return _getIntrinsicDimension((RenderBox child) => child.getMinIntrinsicHeight(width));
   }
 
   @override
   double computeMaxIntrinsicHeight(double width) {
-    return getIntrinsicDimension(firstChild, (RenderBox child) => child.getMaxIntrinsicHeight(width));
+    return _getIntrinsicDimension((RenderBox child) => child.getMaxIntrinsicHeight(width));
   }
 
   @override
@@ -464,57 +463,6 @@ class RenderStack extends RenderBox
     return defaultComputeDistanceToHighestActualBaseline(baseline);
   }
 
-  /// Lays out the positioned `child` according to `alignment` within a Stack of `size`.
-  ///
-  /// Returns true when the child has visual overflow.
-  static bool layoutPositionedChild(RenderBox child, StackParentData childParentData, Size size, Alignment alignment) {
-    assert(childParentData.isPositioned);
-    assert(child.parentData == childParentData);
-
-    bool hasVisualOverflow = false;
-    BoxConstraints childConstraints = const BoxConstraints();
-
-    if (childParentData.left != null && childParentData.right != null)
-      childConstraints = childConstraints.tighten(width: size.width - childParentData.right - childParentData.left);
-    else if (childParentData.width != null)
-      childConstraints = childConstraints.tighten(width: childParentData.width);
-
-    if (childParentData.top != null && childParentData.bottom != null)
-      childConstraints = childConstraints.tighten(height: size.height - childParentData.bottom - childParentData.top);
-    else if (childParentData.height != null)
-      childConstraints = childConstraints.tighten(height: childParentData.height);
-
-    child.layout(childConstraints, parentUsesSize: true);
-
-    double x;
-    if (childParentData.left != null) {
-      x = childParentData.left;
-    } else if (childParentData.right != null) {
-      x = size.width - childParentData.right - child.size.width;
-    } else {
-      x = alignment.alongOffset(size - child.size as Offset).dx;
-    }
-
-    if (x < 0.0 || x + child.size.width > size.width)
-      hasVisualOverflow = true;
-
-    double y;
-    if (childParentData.top != null) {
-      y = childParentData.top;
-    } else if (childParentData.bottom != null) {
-      y = size.height - childParentData.bottom - child.size.height;
-    } else {
-      y = alignment.alongOffset(size - child.size as Offset).dy;
-    }
-
-    if (y < 0.0 || y + child.size.height > size.height)
-      hasVisualOverflow = true;
-
-    childParentData.offset = Offset(x, y);
-
-    return hasVisualOverflow;
-  }
-
   @override
   void performLayout() {
     _resolve();
@@ -579,7 +527,45 @@ class RenderStack extends RenderBox
       if (!childParentData.isPositioned) {
         childParentData.offset = _resolvedAlignment.alongOffset(size - child.size as Offset);
       } else {
-        _hasVisualOverflow = layoutPositionedChild(child, childParentData, size, _resolvedAlignment) || _hasVisualOverflow;
+        BoxConstraints childConstraints = const BoxConstraints();
+
+        if (childParentData.left != null && childParentData.right != null)
+          childConstraints = childConstraints.tighten(width: size.width - childParentData.right - childParentData.left);
+        else if (childParentData.width != null)
+          childConstraints = childConstraints.tighten(width: childParentData.width);
+
+        if (childParentData.top != null && childParentData.bottom != null)
+          childConstraints = childConstraints.tighten(height: size.height - childParentData.bottom - childParentData.top);
+        else if (childParentData.height != null)
+          childConstraints = childConstraints.tighten(height: childParentData.height);
+
+        child.layout(childConstraints, parentUsesSize: true);
+
+        double x;
+        if (childParentData.left != null) {
+          x = childParentData.left;
+        } else if (childParentData.right != null) {
+          x = size.width - childParentData.right - child.size.width;
+        } else {
+          x = _resolvedAlignment.alongOffset(size - child.size as Offset).dx;
+        }
+
+        if (x < 0.0 || x + child.size.width > size.width)
+          _hasVisualOverflow = true;
+
+        double y;
+        if (childParentData.top != null) {
+          y = childParentData.top;
+        } else if (childParentData.bottom != null) {
+          y = size.height - childParentData.bottom - child.size.height;
+        } else {
+          y = _resolvedAlignment.alongOffset(size - child.size as Offset).dy;
+        }
+
+        if (y < 0.0 || y + child.size.height > size.height)
+          _hasVisualOverflow = true;
+
+        childParentData.offset = Offset(x, y);
       }
 
       assert(child.parentData == childParentData);

packages/flutter/test/cupertino/nav_bar_transition_test.dart

@@ -72,9 +72,12 @@ CupertinoPageScaffold scaffoldForNavBar(Widget navBar) {
 }
 
 Finder flying(WidgetTester tester, Finder finder) {
-  final ContainerRenderObjectMixin<RenderBox, StackParentData> theater = tester.renderObject(find.byType(Overlay));
+  final RenderObjectWithChildMixin<RenderStack> theater =
+      tester.renderObject(find.byType(Overlay));
+  final RenderStack theaterStack = theater.child;
   final Finder lastOverlayFinder = find.byElementPredicate((Element element) {
-    return element is RenderObjectElement && element.renderObject == theater.lastChild;
+    return element is RenderObjectElement &&
+        element.renderObject == theaterStack.lastChild;
   });
 
   assert(

packages/flutter/test/material/debug_test.dart

@@ -132,8 +132,8 @@ void main() {
       '     Offstage\n'
       '     _ModalScopeStatus\n'
       '     _ModalScope<dynamic>-[LabeledGlobalKey<_ModalScopeState<dynamic>>#969b7]\n'
-      '     TickerMode\n'
-      '     _OverlayEntryWidget-[LabeledGlobalKey<_OverlayEntryWidgetState>#545d0]\n'
+      '     _OverlayEntry-[LabeledGlobalKey<_OverlayEntryState>#7a3ae]\n'
+      '     Stack\n'
       '     _Theatre\n'
       '     Overlay-[LabeledGlobalKey<OverlayState>#31a52]\n'
       '     _FocusMarker\n'

packages/flutter/test/material/stepper_test.dart

@@ -529,13 +529,12 @@ void main() {
     // which will change depending on where the test is run.
     expect(lines.length, greaterThan(7));
     expect(
-      lines.take(9).join('\n'),
+      lines.take(8).join('\n'),
       equalsIgnoringHashCodes(
         '══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞════════════════════════\n'
         'The following assertion was thrown building Stepper(dirty,\n'
-        'dependencies: [TickerMode,\n'
-        '_LocalizationsScope-[GlobalKey#6b31b]], state:\n'
-        '_StepperState#1bf00):\n'
+        'dependencies: [_LocalizationsScope-[GlobalKey#00000]], state:\n'
+        '_StepperState#00000):\n'
         'Steppers must not be nested.\n'
         'The material specification advises that one should avoid\n'
         'embedding steppers within steppers.\n'

packages/flutter/test/widgets/navigator_test.dart

@@ -1186,33 +1186,6 @@ void main() {
     expect(find.byKey(const ValueKey<String>('/A/B')), findsNothing); // popped
     expect(find.byKey(const ValueKey<String>('/C')), findsOneWidget);
   });
-
-  testWidgets('Pushing opaque Route does not rebuild routes below', (WidgetTester tester) async {
-    // Regression test for https://github.com/flutter/flutter/issues/45797.
-
-    final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-    final Key bottomRoute = UniqueKey();
-    final Key topRoute = UniqueKey();
-    await tester.pumpWidget(
-      MaterialApp(
-        navigatorKey: navigator,
-        routes: <String, WidgetBuilder>{
-          '/' : (BuildContext context) => StatefulTestWidget(key: bottomRoute),
-          '/a': (BuildContext context) => StatefulTestWidget(key: topRoute),
-        },
-      ),
-    );
-    expect(tester.state<StatefulTestState>(find.byKey(bottomRoute)).rebuildCount, 1);
-
-    navigator.currentState.pushNamed('/a');
-    await tester.pumpAndSettle();
-
-    // Bottom route is offstage and did not rebuild.
-    expect(find.byKey(bottomRoute), findsNothing);
-    expect(tester.state<StatefulTestState>(find.byKey(bottomRoute, skipOffstage: false)).rebuildCount, 1);
-
-    expect(tester.state<StatefulTestState>(find.byKey(topRoute)).rebuildCount, 1);
-  });
 }
 
 class NoAnimationPageRoute extends PageRouteBuilder<void> {
@@ -1226,20 +1199,3 @@ class NoAnimationPageRoute extends PageRouteBuilder<void> {
     return super.createAnimationController()..value = 1.0;
   }
 }
-
-class StatefulTestWidget extends StatefulWidget {
-  const StatefulTestWidget({Key key}) : super(key: key);
-
-  @override
-  State<StatefulTestWidget> createState() => StatefulTestState();
-}
-
-class StatefulTestState extends State<StatefulTestWidget> {
-  int rebuildCount = 0;
-
-  @override
-  Widget build(BuildContext context) {
-    rebuildCount += 1;
-    return Container();
-  }
-}