[iOS] DropdownMenu selection tears down the entire iOS accessibility tree when the app uses the Router API (go_router / MaterialApp.router)

Steps to reproduce

Note: as you can tell, I had a lot of help from Claude on this one. It's very similar to #186582, but is different enough (specific to a Gorouter setup) that I'm entering a separate bug - feel free to close as a duplicate if that's the path forward. It's not clear to me whether or not the PR to fix the existing issue will fix this one too.

Clonable repro: https://github.com/elitree/dropdown_gorouter_repro

Run on an iOS simulator or device (flutter run) with useGoRouter = true.
Open Xcode → Open Developer Tool → Accessibility Inspector and target the simulator/device.
Inspect the page — the marker Text, the button, and the dropdown are all present in the accessibility hierarchy.
Tap the DropdownMenu and select any entry.
Re-inspect: the accessibility tree is now empty — the marker Text and the button are gone too, not just the menu. It stays collapsed for the rest of the session.

Isolation

Bisected from a large production app down to this minimal repro, running the same Accessibility Inspector before/after check at each step.

The single differing variable is the routing API:

Host	Identical page	Result after selection
`MaterialApp.router` + `go_router`	✅	Tree collapses
plain `MaterialApp` (Navigator 1.0)	✅	Tree survives

Ruled out (collapse still reproduces without them, or they make no difference):
Google Maps / UiKitView platform views, showModalBottomSheet, SemanticsBinding.ensureSemantics, custom FlutterViewController subclasses, and various plugins. The reproduction requires the combination of the Router API and DropdownMenu/MenuAnchor — neither alone is sufficient.

Relationship to #186582 / #187167

This produces the same end state as #186582 (the iOS accessibility bridge is torn down), but I want to flag a distinction rather than assume it:

It is not addressed by [iOS] Rebind accessibility bridge after view controller changes #187167. That PR fixes the bridge teardown that happens through a new FlutterViewController reattach. I instrumented the VC lifecycle during a reproduced collapse and saw zero lifecycle transitions and a single, constant owner-VC instance — the reattach path the PR patches never fires in this scenario.
It may still share a root cause with [iOS] Accessibility tree is lost after reusing a FlutterEngine with a new FlutterViewController #186582. I could not distinguish, with app/VC-level instrumentation alone, between SetOwnerViewController(self) being re-invoked with the same instance (which still runs accessibility_bridge_.reset()) and a genuinely separate reset path. Confirming that would need engine-level logging in platform_view_ios.mm.

So this is filed as a distinct, minimal repro with a reliable trigger that the in-flight fix won't cover. If maintainers determine it's the same underlying cause as #186582, please treat this as that issue's iOS-Router reproduction (and an indication that #187167's scope may need to expand).

Workaround

Replacing the DropdownMenu with a showModalBottomSheet list picker keeps the accessibility tree intact under the same test.

Note for anyone reproducing app-side

You can't observe this from app code by reading view.accessibilityElements: without an attached assistive-technology consumer, iOS only exposes a shallow placeholder (count ~2) and materializes the full tree lazily for VoiceOver / Accessibility Inspector / XCUITest. Observe the tree with the Accessibility Inspector or an XCUITest assertion, not in-app element counting.

Expected results

Selecting a dropdown entry updates the selection and leaves the accessibility tree
intact — exactly what happens when useGoRouter = false (plain MaterialApp).

Actual results

With useGoRouter = true, selecting any entry wipes the entire iOS accessibility
tree and it is never rebuilt. This breaks VoiceOver and any UIKit-level automation
(XCUITest, Accessibility Inspector, etc.).

Code sample

Requires go_router as a dependency. This is available as a repro project here: https://github.com/elitree/dropdown_gorouter_repro

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

/// true  -> MaterialApp.router + go_router  (a11y tree COLLAPSES after a selection)
/// false -> plain MaterialApp              (tree survives)
const bool useGoRouter = true;

void main() => runApp(const MyApp());

final _router = GoRouter(
  routes: [GoRoute(path: '/', builder: (context, state) => const DropdownPage())],
);

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    if (useGoRouter) {
      return MaterialApp.router(title: 'repro', routerConfig: _router);
    }
    return const MaterialApp(title: 'repro', home: DropdownPage());
  }
}

class DropdownPage extends StatefulWidget {
  const DropdownPage({super.key});
  @override
  State<DropdownPage> createState() => _DropdownPageState();
}

class _DropdownPageState extends State<DropdownPage> {
  String _selected = 'Owner';
  static const _entries = <String>['Owner', 'Owner Last', 'Parcel ID', 'None'];
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('repro')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('MARKER ELEMENT ONE'),
            const SizedBox(height: 24),
            ElevatedButton(onPressed: () {}, child: const Text('MARKER BUTTON TWO')),
            const SizedBox(height: 48),
            DropdownMenu<String>(
              requestFocusOnTap: false,
              initialSelection: _selected,
              onSelected: (v) { if (v != null) setState(() => _selected = v); },
              dropdownMenuEntries: _entries
                  .map((e) => DropdownMenuEntry<String>(value: e, label: e))
                  .toList(),
            ),
            const SizedBox(height: 24),
            Text('Selected: $_selected'),
          ],
        ),
      ),
    );
  }
}

Screenshots or Video

Screenshots / Video demonstration

dropdown_bug.mp4

Logs

fvm flutter run -d 3B4AC0E0-9B84-47D2-969B-0F010184BF4E
Resolving dependencies... 
Downloading packages... 
  matcher 0.12.19 (0.12.20 available)
  meta 1.17.0 (1.18.3 available)
  test_api 0.7.10 (0.7.12 available)
  vector_math 2.2.0 (2.4.0 available)
Got dependencies!
4 packages have newer versions incompatible with dependency constraints.
Try `flutter pub outdated` for more information.
Launching lib/main.dart on iPhone 16e in debug mode...
Running Xcode build...                                                  
Xcode build done.                                           13.0s
Syncing files to device iPhone 16e...                               35ms

Flutter run key commands.
r Hot reload. 🔥🔥🔥
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).

A Dart VM Service on iPhone 16e is available at: http://127.0.0.1:51576/Lt6rZAFG35A=/
The Flutter DevTools debugger and profiler on iPhone 16e is available at:
http://127.0.0.1:51576/Lt6rZAFG35A=/devtools/?uri=ws://127.0.0.1:51576/Lt6rZAFG35A=/ws

Application finished.

Flutter Doctor output

Doctor output

fvm flutter doctor -v
[✓] Flutter (Channel stable, 3.41.9, on macOS 26.5.1 25F80 darwin-arm64, locale en-US) [392ms]
    • Flutter version 3.41.9 on channel stable at /Users/eligeller/fvm/versions/3.41.9
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 00b0c91f06 (5 weeks ago), 2026-04-29 10:03:19 -0700
    • Engine revision 42d3d75a56
    • Dart version 3.11.5
    • DevTools version 2.54.2
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios,
      cli-animations, enable-native-assets, enable-swift-package-manager, omit-legacy-version-file, enable-lldb-debugging,
      enable-uiscene-migration

[✓] Android toolchain - develop for Android devices (Android SDK version 36.1.0) [1,752ms]
    • Android SDK at /Users/eligeller/Library/Android/sdk
    • Emulator version 36.5.10.0 (build_id 15081367) (CL:N/A)
    • Platform android-37.0, build-tools 36.1.0
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
      This is the JDK bundled with the latest Android Studio installation on this machine.
      To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.10+-117844308-b1163.108)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 26.3) [981ms]
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 17C519
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web [4ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Connected device (6 available) [6.1s]
    • Eli iPhone 16 Pro (wireless) (mobile)  • 00008140-000603510193001C            • ios            • iOS 26.5 23F77
    • Eli iPhone 11 (wireless) (mobile)      • 00008030-000E10513A38802E            • ios            • iOS 26.5 23F77
    • Ashley’s iPhone 17 (wireless) (mobile) • 00008150-001571412186401C            • ios            • iOS 26.5.1 23F81
    • iPhone 16e (mobile)                    • 3B4AC0E0-9B84-47D2-969B-0F010184BF4E • ios            •
      com.apple.CoreSimulator.SimRuntime.iOS-26-2 (simulator)
    • macOS (desktop)                        • macos                                • darwin-arm64   • macOS 26.5.1 25F80
      darwin-arm64
    • Chrome (web)                           • chrome                               • web-javascript • Google Chrome
      148.0.7778.216
    ! Error: Browsing on the local area network for Eli’s iPad Pro. Ensure the device is unlocked and attached with a cable or
      associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)

[✓] Network resources [302ms]
    • All expected network resources are available.

• No issues found!

Thanks for the isolation here and for digging into why #187167 won't cover this one.

Sending to the iOS team to match #186582 — they decided that whole accessibility-bridge teardown problem lives in the iOS embedding side rather than framework accessibility, so this fits there too.

I'll leave it open instead of closing it as a duplicate. You've shown the VC-reattach path that #187167 fixes doesn't even fire in your case, so this is worth tracking as its own repro.
Linking #186582 and #187167 for context. Thanks again!

Note upstream issue flutter/flutter#187611 in README

@chunhtai

@chunhtai Do you have any insights into this?

Potentially related: #187198

The triaged-accessibility label is irrelevant if there is no team-accessibility label or fyi-accessibility label.

@QuncCccccc

@QuncCccccc we see your PR - are you working on this? can we assign it to you?

Sure. I assigned myself.

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[iOS] DropdownMenu selection tears down the entire iOS accessibility tree when the app uses the Router API (go_router / MaterialApp.router) #187611

Steps to reproduce

Isolation

Relationship to #186582 / #187167

Workaround

Note for anyone reproducing app-side

Expected results

Actual results

Code sample

Screenshots or Video

Logs

Flutter Doctor output

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[iOS] DropdownMenu selection tears down the entire iOS accessibility tree when the app uses the Router API (go_router / MaterialApp.router) #187611

Description

Steps to reproduce

Isolation

Relationship to #186582 / #187167

Workaround

Note for anyone reproducing app-side

Expected results

Actual results

Code sample

Screenshots or Video

Logs

Flutter Doctor output

Activity

mbcorona commented on Jun 5, 2026

LouiseHsu commented on Jun 11, 2026

LongCatIsLooong commented on Jun 11, 2026

flutter-triage-bot commented on Jul 1, 2026

hellohuanlin commented on Jul 9, 2026

QuncCccccc commented on Jul 9, 2026

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