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Some Dart SDK sources are missing from the Flutter SDK / sky_engine preventing debugging into them #184333
Description
Steps to reproduce
This was originally raised at Dart-Code/Dart-Code#6001 by @FMorschel. A similar issue has come up before at #151171 and #168004. The issue appears to be that Flutter maintains a list of Dart SDK source files to be copied into sky_engine but that set is not complete.
To reproduce:
- Create a new Flutter app in VS Code
- Paste the sample code included below, which calls
.map().toList()on a list - Add a breakpoint on the marked line
- Run the code as a Flutter app (I used Windows, but @FMorschel used Android) and hit the breakpoint
- Try to navigate to the implementation of
new List.of()in the call stack
Expected results
The debugger should open the array_patch.dart file and show you the source code for this frame. This happens correctly in a non-Flutter app (using either a standalone Dart SDK, or the Dart SDK embedded in the Flutter SDK):
Actual results
For a Flutter app (which uses sky_engine instead of the raw Dart SDK paths), the file is missing:
Other stack frames work fine, but there appears to be a few files missing from the sky_engine package compared to the Dart SDK:
Code sample
Code sample
import 'package:flutter/material.dart';
void main() {
runApp(const MainApp());
}
class MainApp extends StatelessWidget {
const MainApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Center(
child: ElevatedButton(
onPressed: () {
final items = [1, 2, 3];
final mapped = items.map((e) => e * 2).toList();
bool test(int e) {
return e > 4; // Breakpoint here
}
mapped.where(test).toList();
},
child: const Text('Trigger List.from'),
),
),
),
);
}
}Screenshots or Video
No response
Logs
No response
Flutter Doctor output
Doctor output
PS D:\Dev\Google\Flutter\Flutter main> flutter doctor -v
[!] Flutter (Channel master, 3.43.0-1.0.pre-353, on Microsoft Windows [Version 10.0.26200.8037], locale en-GB) [2.7s]
• Flutter version 3.43.0-1.0.pre-353 on channel master at D:\Dev\Google\Flutter\Flutter main
! Warning: `dart` on your path resolves to D:\Tools\Dart\Stable\bin\dart.exe, which is not inside your current Flutter SDK checkout at
D:\Dev\Google\Flutter\Flutter main. Consider adding D:\Dev\Google\Flutter\Flutter main\bin to the front of your path.
! Upstream repository [email protected]:DanTup/flutter.git is not a standard remote.
Set environment variable "FLUTTER_GIT_URL" to [email protected]:DanTup/flutter.git to dismiss this error.
• Framework revision 97197427ce (2 hours ago), 2026-03-30 04:55:10 -0400
• Engine revision 97197427ce
• Dart version 3.12.0 (build 3.12.0-300.0.dev)
• DevTools version 2.57.0-dev.0
• 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, enable-riscv64
• If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and
upgrades.
[✓] Windows Version (11 Pro 64-bit, 25H2, 2009) [562ms]
[!] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [1,481ms]
• Android SDK at C:\Users\danny\AppData\Local\Android\sdk
• Emulator version 36.3.10.0 (build_id 14472402) (CL:N/A)
• Platform android-36, build-tools 35.0.0
• Java binary at: C:\Program Files\Android\Android Studio\jbr\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 21.0.8+-14196175-b1038.72)
! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
[✓] Chrome - develop for the web [50ms]
• Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe
[✓] Visual Studio - develop Windows apps (Visual Studio Community 2026 18.2.0) [49ms]
• Visual Studio at C:\Program Files\Microsoft Visual Studio\18\Community
• Visual Studio Community 2026 version 18.2.11408.102
• Windows 10 SDK version 10.0.26100.0
[✓] Connected device (3 available) [91ms]
• Windows (desktop) • windows • windows-x64 • Microsoft Windows [Version 10.0.26200.8037]
• Chrome (web) • chrome • web-javascript • Google Chrome 146.0.7680.165
• Edge (web) • edge • web-javascript • Microsoft Edge 144.0.3719.92
[✓] Network resources [525ms]
• All expected network resources are available.
! Doctor found issues in 2 categories.
Activity
FMorschel commentedon Mar 30, 2026
Is there any way we could identify this automatically and send data to the Flutter team whenever this happens? So the user doesn't need to keep opening issues for these?
saurabh-mirajkar commentedon Mar 31, 2026
@DanTup Thanks for the report. Labelling for
team-engineto investigate further.[vm] Add some missing files to the vm_internal_sdk_sources list
jason-simmons commentedon Apr 6, 2026
Fixed by dart-lang/sdk@37bf6b5
DanTup commentedon Apr 6, 2026
Thanks!
DanTup commentedon Apr 6, 2026
@FMorschel I missed your comment above:
I can't think of a good way to do this, but I do wonder whether a test somewhere could compare the two. Although having test fail here in Flutter when it requires an SDK change to fix would probably be inconvenient. I'm not all that familiar with these files though, I wonder if @jason-simmons has any ideas.
github-actions commentedon Apr 20, 2026
This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of
flutter doctor -vand a minimal reproduction of the issue.