Multiple inner ScrollPositions of NestedScrollView reset when scrolling all the way to the top

[AhmedLSayed9]

Steps to reproduce

1. Run the sample
2. Scroll down
3. Change Tab to Popular
4. Scroll down
5. Change Tab to Latest
6. Scroll all the way to the top
7. Check other tabs

The issue has been partially resolved by #157756.
However, as noted by @nate-thegrate in #157756 (comment), scrolling all the way to the top of the view will still reset the scroll positions.

Expected results

I expect the other tabs to maintain their scroll positions.

Actual results

Going all the way to the top will reset the other tabs' scroll positions.

Code sample

Code sample

import 'package:flutter/material.dart';

void main() {
  runApp(
    const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(body: NewsScreen()),
    ),
  );
}

class NewsScreen extends StatelessWidget {
  const NewsScreen({super.key});

  static const List<String> _tabs = <String>['Featured', 'Popular', 'Latest'];

  static final List<Widget> _tabViews = <Widget>[
    for (final String name in _tabs)
      SafeArea(
        top: false,
        bottom: false,
        child: Builder(builder: (BuildContext context) {
          final handle = NestedScrollView.sliverOverlapAbsorberHandleFor(context);

          return NotificationListener<ScrollNotification>(
            onNotification: (ScrollNotification notification) => true,
            child: CustomScrollView(
              key: PageStorageKey<String>(name),
              slivers: <Widget>[
                SliverOverlapInjector(handle: handle),
                SliverPadding(
                  padding: const EdgeInsets.all(8.0),
                  sliver: SliverList(
                    delegate: SliverChildBuilderDelegate(
                      childCount: 30,
                      (BuildContext context, int index) => Container(
                        margin: const EdgeInsets.only(bottom: 8),
                        width: double.infinity,
                        height: 150,
                        color: const Color(0xFFB0A4C8),
                        alignment: Alignment.center,
                        child: Text(
                          '$name $index',
                          style: const TextStyle(fontWeight: FontWeight.w600),
                        ),
                      ),
                    ),
                  ),
                ),
              ],
            ),
          );
        }),
      ),
  ];

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: _tabs.length,
      child: NestedScrollView(
        headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) => <Widget>[
          SliverOverlapAbsorber(
            handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
            sliver: SliverSafeArea(
              top: false,
              sliver: SliverAppBar(
                title: const Text('Tab Demo'),
                floating: true,
                pinned: true,
                snap: true,
                forceElevated: innerBoxIsScrolled,
                bottom: TabBar(
                  tabs: _tabs.map((String name) => Tab(text: name)).toList(),
                ),
              ),
            ),
          ),
        ],
        body: TabBarView(children: _tabViews),
      ),
    );
  }
}

Screenshots or Video

Screenshots / Video demonstration

Screen.Recording.2025-03-19.at.5.26.49.AM.mov

Logs

No response

Flutter Doctor output

Doctor output

[✓] Flutter (Channel stable, 3.29.2, on macOS 15.2 24C101 darwin-arm64, locale en-EG) [639ms]
    • Flutter version 3.29.2 on channel stable at /Users/ahmedelsayed/.puro/envs/stable/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision c236373904 (5 days ago), 2025-03-13 16:17:06 -0400
    • Engine revision 010c8a806b
    • Dart version 3.7.0 (build 3.7.0-323.0.dev)
    • DevTools version 2.42.0

[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [3.8s]
    • Android SDK at /Users/ahmedelsayed/Library/Android/sdk
    • Platform android-35, build-tools 35.0.0
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      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version Java(TM) SE Runtime Environment (build 19.0.2+7-44)
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    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16C5032a
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    • Java version OpenJDK Runtime Environment (build 21.0.3+-79915917-b509.11)

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• No issues found!

[darshankawar]

@AhmedLSayed9
Can you check if this is similar to #126425 ?

[AhmedLSayed9]

@AhmedLSayed9 Can you check if this is similar to #126425 ?

Nope. It's totally different.
The mentioned issue is about preserving the horizontal scroll of TabBar items.

[darshankawar]

I see, please check this as well to confirm if it resembles your case or not.

[AhmedLSayed9]

I see, please check this as well to confirm if it resembles your case or not.

They might be related but not exactly the same.

This issue specifically describes how scrolling all the way to the top resets all taps, even those far away (Doesn't require AutomaticKeepAliveClientMixin).

The other issue is about how scrolling in one tab causes other tabs to scroll the same distance (Requires AutomaticKeepAliveClientMixin).

[darshankawar]

Thanks for the update. I was able to replicate the reported behavior on latest sdk versions.

stable : 3.29.2
master : 3.31.0-1.0.pre.135

[Piinks]

Thanks @AhmedLSayed9 the root cause here and in #159123 is the same due to the use of the primary scroll controller. I am going to close this as a dupe of that issue.