Revert "[framework] inline AbstractNode into RenderObject" (#104257)

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

@@ -1566,7 +1566,9 @@ class _ActionButtonParentDataWidget
       parentData.isPressed = isPressed;
 
       // Force a repaint.
-      renderObject.parent?.markNeedsPaint();
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject)
+        targetParent.markNeedsPaint();
     }
   }
 

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

@@ -4,6 +4,7 @@
 
 import 'dart:math' as math;
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 
@@ -1085,9 +1086,9 @@ class TableRowInkWell extends InkResponse {
   RectCallback getRectCallback(RenderBox referenceBox) {
     return () {
       RenderObject cell = referenceBox;
-      RenderObject? table = cell.parent;
+      AbstractNode? table = cell.parent;
       final Matrix4 transform = Matrix4.identity();
-      while (table != null && table is! RenderTable) {
+      while (table is RenderObject && table is! RenderTable) {
         table.applyPaintTransform(cell, transform);
         assert(table == cell.parent);
         cell = table;

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

@@ -683,7 +683,7 @@ abstract class InkFeature {
     RenderObject node = referenceBox;
     while (node != _controller) {
       final RenderObject childNode = node;
-      node = node.parent!;
+      node = node.parent! as RenderObject;
       if (!node.paintsChild(childNode)) {
         // Some node between the reference box and this would skip painting on
         // the reference box, so bail out early and avoid unnecessary painting.

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

@@ -2145,7 +2145,7 @@ abstract class RenderBox extends RenderObject {
     assert(!_debugDoingBaseline, 'Please see the documentation for computeDistanceToActualBaseline for the required calling conventions of this method.');
     assert(!debugNeedsLayout);
     assert(() {
-      final RenderObject? parent = this.parent;
+      final RenderObject? parent = this.parent as RenderObject?;
       if (owner!.debugDoingLayout)
         return (RenderObject.debugActiveLayout == parent) && parent!.debugDoingThisLayout;
       if (owner!.debugDoingPaint)
@@ -2367,7 +2367,7 @@ abstract class RenderBox extends RenderObject {
 
   @override
   void markNeedsLayout() {
-    if (_clearCachedData() && parent != null) {
+    if (_clearCachedData() && parent is RenderObject) {
       markParentNeedsLayout();
       return;
     }

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

@@ -1039,7 +1039,7 @@ class RenderListWheelViewport
     // `child` will be the last RenderObject before the viewport when walking up from `target`.
     RenderObject child = target;
     while (child.parent != this)
-      child = child.parent!;
+      child = child.parent! as RenderObject;
 
     final ListWheelParentData parentData = child.parentData! as ListWheelParentData;
     final double targetOffset = parentData.offset.dy; // the so-called "centerPosition"

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

@@ -43,7 +43,7 @@ abstract class RenderAbstractViewport extends RenderObject {
     while (object != null) {
       if (object is RenderAbstractViewport)
         return object;
-      object = object.parent;
+      object = object.parent as RenderObject?;
     }
     return null;
   }
@@ -764,7 +764,7 @@ abstract class RenderViewportBase<ParentDataClass extends ContainerParentDataMix
     RenderBox? pivot;
     bool onlySlivers = target is RenderSliver; // ... between viewport and `target` (`target` included).
     while (child.parent != this) {
-      final RenderObject parent = child.parent!;
+      final RenderObject parent = child.parent! as RenderObject;
       assert(parent != null, '$target must be a descendant of $this');
       if (child is RenderBox) {
         pivot = child;
@@ -1214,7 +1214,7 @@ abstract class RenderViewportBase<ParentDataClass extends ContainerParentDataMix
     } else {
       // `descendant` is between leading and trailing edge and hence already
       //  fully shown on screen. No action necessary.
-      final Matrix4 transform = descendant.getTransformTo(viewport.parent);
+      final Matrix4 transform = descendant.getTransformTo(viewport.parent! as RenderObject);
       return MatrixUtils.transformRect(transform, rect ?? descendant.paintBounds);
     }
 

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

@@ -2169,8 +2169,8 @@ class LayoutId extends ParentDataWidget<MultiChildLayoutParentData> {
     final MultiChildLayoutParentData parentData = renderObject.parentData! as MultiChildLayoutParentData;
     if (parentData.id != id) {
       parentData.id = id;
-      final RenderObject? targetParent = renderObject.parent;
-      if (targetParent != null)
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject)
         targetParent.markNeedsLayout();
     }
   }
@@ -4132,8 +4132,8 @@ class Positioned extends ParentDataWidget<StackParentData> {
     }
 
     if (needsLayout) {
-      final RenderObject? targetParent = renderObject.parent;
-      if (targetParent != null)
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject)
         targetParent.markNeedsLayout();
     }
   }
@@ -4992,8 +4992,8 @@ class Flexible extends ParentDataWidget<FlexParentData> {
     }
 
     if (needsLayout) {
-      final RenderObject? targetParent = renderObject.parent;
-      if (targetParent != null)
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject)
         targetParent.markNeedsLayout();
     }
   }

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

@@ -1747,8 +1747,8 @@ class KeepAlive extends ParentDataWidget<KeepAliveParentDataMixin> {
     final KeepAliveParentDataMixin parentData = renderObject.parentData! as KeepAliveParentDataMixin;
     if (parentData.keepAlive != keepAlive) {
       parentData.keepAlive = keepAlive;
-      final RenderObject? targetParent = renderObject.parent;
-      if (targetParent != null && !keepAlive)
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject && !keepAlive)
         targetParent.markNeedsLayout(); // No need to redo layout if it became true.
     }
   }

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

@@ -433,8 +433,8 @@ class TableCell extends ParentDataWidget<TableCellParentData> {
     final TableCellParentData parentData = renderObject.parentData! as TableCellParentData;
     if (parentData.verticalAlignment != verticalAlignment) {
       parentData.verticalAlignment = verticalAlignment;
-      final RenderObject? targetParent = renderObject.parent;
-      if (targetParent != null)
+      final AbstractNode? targetParent = renderObject.parent;
+      if (targetParent is RenderObject)
         targetParent.markNeedsLayout();
     }
   }

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

@@ -552,7 +552,7 @@ class _ScreenshotPaintingContext extends PaintingContext {
   }) {
     RenderObject repaintBoundary = renderObject;
     while (repaintBoundary != null && !repaintBoundary.isRepaintBoundary) {
-      repaintBoundary = repaintBoundary.parent!;
+      repaintBoundary = repaintBoundary.parent! as RenderObject;
     }
     assert(repaintBoundary != null);
     final _ScreenshotData data = _ScreenshotData(target: renderObject);
@@ -1510,7 +1510,7 @@ mixin WidgetInspectorService {
     final List<RenderObject> chain = <RenderObject>[];
     while (renderObject != null) {
       chain.add(renderObject);
-      renderObject = renderObject.parent;
+      renderObject = renderObject.parent as RenderObject?;
     }
     return _followDiagnosticableChain(chain.reversed.toList());
   }
@@ -2565,7 +2565,7 @@ class _RenderInspectorOverlay extends RenderBox {
     context.addLayer(_InspectorOverlayLayer(
       overlayRect: Rect.fromLTWH(offset.dx, offset.dy, size.width, size.height),
       selection: selection,
-      rootRenderObject: parent != null ? parent! : null,
+      rootRenderObject: parent is RenderObject ? parent! as RenderObject : null,
     ));
   }
 }
@@ -2841,14 +2841,14 @@ class _InspectorOverlayLayer extends Layer {
   /// overlays in the same app (i.e. an storyboard), a selected or candidate
   /// render object may not belong to this tree.
   bool _isInInspectorRenderObjectTree(RenderObject child) {
-    RenderObject? current = child.parent;
+    RenderObject? current = child.parent as RenderObject?;
     while (current != null) {
       // We found the widget inspector render object.
       if (current is RenderStack
           && current.lastChild is _RenderInspectorOverlay) {
         return rootRenderObject == current;
       }
-      current = current.parent;
+      current = current.parent as RenderObject?;
     }
     return false;
   }

packages/flutter/test/material/tooltip_test.dart

@@ -1941,5 +1941,5 @@ Future<void> testGestureTap(WidgetTester tester, Finder tooltip) async {
 SemanticsNode findDebugSemantics(RenderObject object) {
   if (object.debugSemantics != null)
     return object.debugSemantics!;
-  return findDebugSemantics(object.parent!);
+  return findDebugSemantics(object.parent! as RenderObject);
 }

packages/flutter/test/material/tooltip_theme_test.dart

@@ -1357,5 +1357,5 @@ void main() {
 SemanticsNode findDebugSemantics(RenderObject object) {
   if (object.debugSemantics != null)
     return object.debugSemantics!;
-  return findDebugSemantics(object.parent!);
+  return findDebugSemantics(object.parent! as RenderObject);
 }

packages/flutter/test/rendering/cached_intrinsics_test.dart

@@ -118,7 +118,7 @@ void main() {
     expect(parentData!.offset.dy, -(viewHeight / 2.0));
     expect(test.calls, 2); // The layout constraints change will clear the cached data.
 
-    final RenderObject parent = test.parent!;
+    final RenderObject parent = test.parent! as RenderObject;
     expect(parent.debugNeedsLayout, false);
 
     // Do not forget notify parent dirty after the cached data be cleared by `layout()`

packages/flutter/test/rendering/editable_test.dart

@@ -935,7 +935,7 @@ void main() {
       editable.painter = null;
       editable.paintCount = 0;
 
-      final RenderObject? parent = editable.parent;
+      final AbstractNode? parent = editable.parent;
       if (parent is RenderConstrainedBox)
         parent.child = null;
     });

packages/flutter/test/rendering/non_render_object_root_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'rendering_tester.dart';
+
+class RealRoot extends AbstractNode {
+  RealRoot(this.child) {
+    adoptChild(child);
+  }
+
+  final RenderObject child;
+
+  @override
+  void redepthChildren() {
+    redepthChild(child);
+  }
+
+  @override
+  void attach(Object owner) {
+    super.attach(owner);
+    child.attach(owner as PipelineOwner);
+  }
+
+  @override
+  void detach() {
+    super.detach();
+    child.detach();
+  }
+
+  @override
+  PipelineOwner? get owner => super.owner as PipelineOwner?;
+
+  void layout() {
+    child.layout(BoxConstraints.tight(const Size(500.0, 500.0)));
+  }
+}
+
+void main() {
+  TestRenderingFlutterBinding.ensureInitialized();
+
+  test('non-RenderObject roots', () {
+    RenderPositionedBox child;
+    final RealRoot root = RealRoot(
+      child = RenderPositionedBox(
+        child: RenderSizedBox(const Size(100.0, 100.0)),
+      ),
+    );
+    root.attach(PipelineOwner());
+
+    child.scheduleInitialLayout();
+    root.layout();
+
+    child.markNeedsLayout();
+    root.layout();
+  });
+}

packages/flutter/test/rendering/proxy_box_test.dart

@@ -689,9 +689,9 @@ void main() {
 
   test('Offstage implements paintsChild correctly', () {
     final RenderBox box = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
-    final RenderProxyBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
+    final RenderBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
     final RenderOffstage offstage = RenderOffstage(offstage: false, child: box);
-    parent.child  = offstage;
+    parent.adoptChild(offstage);
 
     expect(offstage.paintsChild(box), true);
 
@@ -702,9 +702,9 @@ void main() {
 
   test('Opacity implements paintsChild correctly', () {
     final RenderBox box = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
-    final RenderProxyBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
+    final RenderBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
     final RenderOpacity opacity = RenderOpacity(child: box);
-    parent.child = opacity;
+    parent.adoptChild(opacity);
 
     expect(opacity.paintsChild(box), true);
 
@@ -714,11 +714,11 @@ void main() {
   });
 
   test('AnimatedOpacity sets paint matrix to zero when alpha == 0', () {
-    final RenderProxyBox box = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
-    final RenderProxyBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
+    final RenderBox box = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
+    final RenderBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
     final AnimationController opacityAnimation = AnimationController(value: 1, vsync: FakeTickerProvider());
     final RenderAnimatedOpacity opacity = RenderAnimatedOpacity(opacity: opacityAnimation, child: box);
-    parent.child = opacity;
+    parent.adoptChild(opacity);
 
     // Make it listen to the animation.
     opacity.attach(PipelineOwner());
@@ -732,10 +732,10 @@ void main() {
 
   test('AnimatedOpacity sets paint matrix to zero when alpha == 0 (sliver)', () {
     final RenderSliver sliver = RenderSliverToBoxAdapter(child: RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20)));
-    final RenderSliverPadding parent = RenderSliverPadding(padding: const EdgeInsets.all(4));
+    final RenderBox parent = RenderConstrainedBox(additionalConstraints: const BoxConstraints.tightFor(width: 20));
     final AnimationController opacityAnimation = AnimationController(value: 1, vsync: FakeTickerProvider());
     final RenderSliverAnimatedOpacity opacity = RenderSliverAnimatedOpacity(opacity: opacityAnimation, sliver: sliver);
-    parent.child = opacity;
+    parent.adoptChild(opacity);
 
     // Make it listen to the animation.
     opacity.attach(PipelineOwner());

packages/flutter/test/widgets/heroes_test.dart

@@ -2924,8 +2924,8 @@ Future<void> main() async {
     final ScrollController controller = ScrollController();
 
     RenderAnimatedOpacity? findRenderAnimatedOpacity() {
-      RenderObject? parent = tester.renderObject(find.byType(Placeholder));
-      while (parent != null && parent is! RenderAnimatedOpacity) {
+      AbstractNode? parent = tester.renderObject(find.byType(Placeholder));
+      while (parent is RenderObject && parent is! RenderAnimatedOpacity) {
         parent = parent.parent;
       }
       return parent is RenderAnimatedOpacity ? parent : null;

packages/flutter_driver/lib/src/common/handler_factory.dart

@@ -308,7 +308,7 @@ mixin CommandHandlerFactory {
     SemanticsNode? node;
     while (renderObject != null && node == null) {
       node = renderObject.debugSemantics;
-      renderObject = renderObject.parent;
+      renderObject = renderObject.parent as RenderObject?;
     }
     if (node == null)
       throw StateError('No semantics data found');

packages/flutter_test/lib/src/_matchers_io.dart

@@ -23,7 +23,7 @@ Future<ui.Image> captureImage(Element element) {
   assert(element.renderObject != null);
   RenderObject renderObject = element.renderObject!;
   while (!renderObject.isRepaintBoundary) {
-    renderObject = renderObject.parent!;
+    renderObject = renderObject.parent! as RenderObject;
   }
   assert(!renderObject.debugNeedsPaint);
   final OffsetLayer layer = renderObject.debugLayer! as OffsetLayer;

packages/flutter_test/lib/src/_matchers_web.dart

@@ -82,7 +82,7 @@ RenderObject _findRepaintBoundary(Element element) {
   assert(element.renderObject != null);
   RenderObject renderObject = element.renderObject!;
   while (!renderObject.isRepaintBoundary) {
-    renderObject = renderObject.parent!;
+    renderObject = renderObject.parent! as RenderObject;
   }
   return renderObject;
 }

packages/flutter_test/lib/src/controller.dart

@@ -1168,7 +1168,7 @@ abstract class WidgetController {
     RenderObject? renderObject = element.findRenderObject();
     SemanticsNode? result = renderObject?.debugSemantics;
     while (renderObject != null && (result == null || result.isMergedIntoParent)) {
-      renderObject = renderObject.parent;
+      renderObject = renderObject.parent as RenderObject?;
       result = renderObject?.debugSemantics;
     }
     if (result == null)