fix debug paint crash when axis direction inverted (#37033)

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

@@ -1425,6 +1425,10 @@ abstract class RenderSliver extends RenderObject {
   /// This means that the dimensions may be negative.
   ///
   /// This is only valid after [layout] has completed.
+  ///
+  /// See also:
+  ///
+  ///  * [getAbsoluteSize], which returns absolute size.
   @protected
   Size getAbsoluteSizeRelativeToOrigin() {
     assert(geometry != null);
@@ -1442,6 +1446,30 @@ abstract class RenderSliver extends RenderObject {
     return null;
   }
 
+  /// This returns the absolute [Size] of the sliver.
+  ///
+  /// The dimensions are always positive and calling this is only valid after
+  /// [layout] has completed.
+  ///
+  /// See also:
+  ///
+  ///  * [getAbsoluteSizeRelativeToOrigin], which returns the size relative to
+  ///    the leading edge of the sliver.
+  @protected
+  Size getAbsoluteSize() {
+    assert(geometry != null);
+    assert(!debugNeedsLayout);
+    switch (constraints.axisDirection) {
+      case AxisDirection.up:
+      case AxisDirection.down:
+        return Size(constraints.crossAxisExtent, geometry.paintExtent);
+      case AxisDirection.right:
+      case AxisDirection.left:
+        return Size(geometry.paintExtent, constraints.crossAxisExtent);
+    }
+    return null;
+  }
+
   void _debugDrawArrow(Canvas canvas, Paint paint, Offset p0, Offset p1, GrowthDirection direction) {
     assert(() {
       if (p0 == p1)

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

@@ -328,12 +328,12 @@ class RenderSliverPadding extends RenderSliver with RenderObjectWithChildMixin<R
     super.debugPaint(context, offset);
     assert(() {
       if (debugPaintSizeEnabled) {
-        final Size parentSize = getAbsoluteSizeRelativeToOrigin();
+        final Size parentSize = getAbsoluteSize();
         final Rect outerRect = offset & parentSize;
         Size childSize;
         Rect innerRect;
         if (child != null) {
-          childSize = child.getAbsoluteSizeRelativeToOrigin();
+          childSize = child.getAbsoluteSize();
           final SliverPhysicalParentData childParentData = child.parentData;
           innerRect = (offset + childParentData.paintOffset) & childSize;
           assert(innerRect.top >= outerRect.top);

packages/flutter/test/rendering/debug_test.dart

@@ -124,4 +124,70 @@ void main() {
     expect(b.debugPaint, isNot(paints..rect(color: const Color(0x90909090))));
     debugPaintSizeEnabled = false;
   });
+
+  test('debugPaintPadding from render objects with inverted direction vertical', () {
+    debugPaintSizeEnabled = true;
+    RenderSliver s;
+    final RenderViewport root = RenderViewport(
+      axisDirection: AxisDirection.up,
+      crossAxisDirection: AxisDirection.right,
+      offset: ViewportOffset.zero(),
+      children: <RenderSliver>[
+        s = RenderSliverPadding(
+          padding: const EdgeInsets.all(10.0),
+          child: RenderSliverToBoxAdapter(
+            child: RenderPadding(
+              padding: const EdgeInsets.all(10.0),
+            ),
+          ),
+        ),
+      ],
+    );
+    layout(root);
+    dynamic error;
+    try {
+      s.debugPaint(
+        PaintingContext(
+          ContainerLayer(), const Rect.fromLTRB(0.0, 0.0, 800.0, 600.0)),
+        const Offset(0.0, 500)
+      );
+    } catch(e) {
+      error = e;
+    }
+    expect(error, isNull);
+    debugPaintSizeEnabled = false;
+  });
+
+  test('debugPaintPadding from render objects with inverted direction horizontal', () {
+    debugPaintSizeEnabled = true;
+    RenderSliver s;
+    final RenderViewport root = RenderViewport(
+      axisDirection: AxisDirection.left,
+      crossAxisDirection: AxisDirection.down,
+      offset: ViewportOffset.zero(),
+      children: <RenderSliver>[
+        s = RenderSliverPadding(
+          padding: const EdgeInsets.all(10.0),
+          child: RenderSliverToBoxAdapter(
+            child: RenderPadding(
+              padding: const EdgeInsets.all(10.0),
+            ),
+          ),
+        ),
+      ],
+    );
+    layout(root);
+    dynamic error;
+    try {
+      s.debugPaint(
+        PaintingContext(
+          ContainerLayer(), const Rect.fromLTRB(0.0, 0.0, 800.0, 600.0)),
+        const Offset(0.0, 500)
+      );
+    } catch(e) {
+      error = e;
+    }
+    expect(error, isNull);
+    debugPaintSizeEnabled = false;
+  });
 }