Reland [SingleChildScrollView] Correct the offset pixels if it is out of range during layout (#136871)

Reland flutter/flutter#136239 which was reverted by flutter/flutter#136744
Fixes flutter/flutter#105733
FIxes flutter/flutter#135865

Do not merge before the customer finish the migration. @Piinks

Author: xu-baolin

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

@@ -495,6 +495,14 @@ class _RenderSingleChildViewport extends RenderBox with RenderObjectWithChildMix
       size = constraints.constrain(child!.size);
     }
 
+    if (offset.hasPixels) {
+      if (offset.pixels > _maxScrollExtent) {
+        offset.correctBy(_maxScrollExtent - offset.pixels);
+      } else if (offset.pixels < _minScrollExtent) {
+        offset.correctBy(_minScrollExtent - offset.pixels);
+      }
+    }
+
     offset.applyViewportDimension(_viewportExtent);
     offset.applyContentDimensions(_minScrollExtent, _maxScrollExtent);
   }

packages/flutter/test/widgets/clamp_overscrolls_test.dart

@@ -92,19 +92,40 @@ void main() {
     expect(scrollable.position.pixels, equals(50.0));
   });
 
-  testWidgetsWithLeakTracking('ClampingScrollPhysics handles out of bounds ScrollPosition', (WidgetTester tester) async {
+  testWidgetsWithLeakTracking('ClampingScrollPhysics handles out of bounds ScrollPosition - initialScrollOffset', (WidgetTester tester) async {
     Future<void> testOutOfBounds(ScrollPhysics physics, double initialOffset, double expectedOffset) async {
       final ScrollController scrollController = ScrollController(initialScrollOffset: initialOffset);
       addTearDown(scrollController.dispose);
       await tester.pumpWidget(buildFrame(physics, scrollController: scrollController));
       final ScrollableState scrollable = tester.state(find.byType(Scrollable));
 
-      expect(scrollable.position.pixels, equals(initialOffset));
-      await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle
+      // The initialScrollOffset will be corrected during the first frame.
       expect(scrollable.position.pixels, equals(expectedOffset));
     }
 
     await testOutOfBounds(const ClampingScrollPhysics(), -400.0, 0.0);
     await testOutOfBounds(const ClampingScrollPhysics(), 800.0, 50.0);
   });
+
+  testWidgetsWithLeakTracking('ClampingScrollPhysics handles out of bounds ScrollPosition - jumpTo', (WidgetTester tester) async {
+    Future<void> testOutOfBounds(ScrollPhysics physics, double targetOffset, double endingOffset) async {
+      final ScrollController scrollController = ScrollController();
+      addTearDown(scrollController.dispose);
+      await tester.pumpWidget(buildFrame(physics, scrollController: scrollController));
+      final ScrollableState scrollable = tester.state(find.byType(Scrollable));
+
+      expect(scrollable.position.pixels, equals(0.0));
+
+      scrollController.jumpTo(targetOffset);
+      await tester.pump();
+
+      expect(scrollable.position.pixels, equals(targetOffset));
+
+      await tester.pump(const Duration(seconds: 1)); // Allow overscroll animation to settle
+      expect(scrollable.position.pixels, equals(endingOffset));
+    }
+
+    await testOutOfBounds(const ClampingScrollPhysics(), -400.0, 0.0);
+    await testOutOfBounds(const ClampingScrollPhysics(), 800.0, 50.0);
+  });
 }

packages/flutter/test/widgets/scroll_notification_test.dart

@@ -23,37 +23,45 @@ void main() {
     }
     await tester.pumpWidget(buildFrame(1200.0));
     expect(events.length, 1);
+    ScrollMetricsNotification event = events[0] as ScrollMetricsNotification;
+    expect(event.metrics.extentBefore, 0.0);
+    expect(event.metrics.extentInside, 600.0);
+    expect(event.metrics.extentAfter, 600.0);
+    expect(event.metrics.extentTotal, 1200.0);
 
     events.clear();
     await tester.pumpWidget(buildFrame(1000.0));
     // Change the content dimensions will trigger a new event.
     expect(events.length, 1);
-    ScrollMetricsNotification event = events[0] as ScrollMetricsNotification;
+    event = events[0] as ScrollMetricsNotification;
     expect(event.metrics.extentBefore, 0.0);
     expect(event.metrics.extentInside, 600.0);
     expect(event.metrics.extentAfter, 400.0);
     expect(event.metrics.extentTotal, 1000.0);
 
     events.clear();
     final TestGesture gesture = await tester.startGesture(const Offset(100.0, 100.0));
-    expect(events.length, 1);
-    // user scroll do not trigger the ScrollContentMetricsNotification.
-    expect(events[0] is ScrollStartNotification, true);
-
-    events.clear();
+    await tester.pump(const Duration(seconds: 1));
     await gesture.moveBy(const Offset(-10.0, -10.0));
-    expect(events.length, 2);
-    // User scroll do not trigger the ScrollContentMetricsNotification.
-    expect(events[0] is UserScrollNotification, true);
-    expect(events[1] is ScrollUpdateNotification, true);
+    await tester.pump(const Duration(seconds: 1));
+    await gesture.up();
+    await tester.pump(const Duration(seconds: 1));
+
+    expect(events.length, 5);
+    // user scroll do not trigger the ScrollMetricsNotification.
+    expect(events[0] is ScrollStartNotification, true);
+    expect(events[1] is UserScrollNotification, true);
+    expect(events[2] is ScrollUpdateNotification, true);
+    expect(events[3] is ScrollEndNotification, true);
+    expect(events[4] is UserScrollNotification, true);
 
     events.clear();
     // Change the content dimensions again.
     await tester.pumpWidget(buildFrame(500.0));
     expect(events.length, 1);
     event = events[0] as ScrollMetricsNotification;
-    expect(event.metrics.extentBefore, 10.0);
-    expect(event.metrics.extentInside, 590.0);
+    expect(event.metrics.extentBefore, 0.0);
+    expect(event.metrics.extentInside, 600.0);
     expect(event.metrics.extentAfter, 0.0);
     expect(event.metrics.extentTotal, 600.0);
 

packages/flutter/test/widgets/scrollable_test.dart

@@ -1039,7 +1039,7 @@ void main() {
 
     // Make the outer constraints larger that the scrollable widget is no longer able to scroll.
     await tester.pumpWidget(build(300.0));
-    expect(controller.position.pixels, 100.0);
+    expect(controller.position.pixels, 0.0);
     expect(controller.position.maxScrollExtent, 0.0);
 
     // Hover over the scroll view and create a zero offset pointer scroll.