Flutter test throws on Failed host lookup when debugging

[thumbert]

Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Steps to reproduce

Unfortunately I can only describe the problem verbally. It is very much similar to https://github.com/dart-lang/sdk/issues/53334

import 'package:http/http.dart' as http;
import 'package:flutter_test/flutter_test.dart';

Future<void> main() async {
   final uri = 'xxxx';  // internal server name
   var response = await http.get(Uri.parse(uri));
   print(response.statusCode);  // prints 200
 
  test('throws in debug mode!', () async {
    var response = await http.get(Uri.parse(uri));  // this line throws!
    expect(response.statusCode, 200);   // put a break point on this line and start debug
  });
}

If I run this file with flutter it runs OK. But if I start a debugging session, it throws inside the test.

If I run the same file with dart (using package test), it runs OK and it stops on the break point too (no issue!).

I don't understand what is flutter test doing that is different than a dart test in this regard.

The server name is a load balancer. If I run the flutter test with the underlying IP address of one of the servers behind the balancer, it does not throw. Because I can use the IP address directly, I have a workaround, but it would be nice if flutter test will do the same thing as dart test and not throw in debug mode.

Thanks,
T

Expected results

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Actual results

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Flutter Doctor output

Doctor output

$ flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[!] Flutter (Channel stable, 3.13.9, on Microsoft Windows [Version 10.0.19044.3570], locale en-US)
    ! Warning: `dart` on your path resolves to C:\...\dart.exe, which is not inside your current Flutter SDK checkout at C:\...\flutter. Consider adding C:\...\flutter\bin to the front of your path.
[√] Windows Version (Installed version of Windows is version 10 or higher)
[X] Android toolchain - develop for Android devices
    X Unable to locate Android SDK.
      Install Android Studio from: https://developer.android.com/studio/index.html
      On first launch it will assist you in installing the Android SDK components.
      (or visit https://flutter.dev/docs/get-started/install/windows#android-setup for detailed instructions).
      If the Android SDK has been installed to a custom location, please use
      `flutter config --android-sdk` to update to that location.

[√] Chrome - develop for the web
[√] Visual Studio - develop Windows apps (Visual Studio Build Tools 2022 17.6.4)
[!] Android Studio (not installed)
[√] IntelliJ IDEA Ultimate Edition (version 2019.3)
[√] IntelliJ IDEA Community Edition (version 2023.2)
[√] VS Code (version 1.42.0)
[√] Connected device (3 available)
[√] Network resources

! Doctor found issues in 3 categories.

[darshankawar]

Thanks for the report @thumbert
Can you provide the error log that shows while debugging the said test ?

I tried below code sample but with debug, I was able to get the test passed with 200 as status code.

200
00:04 +1: All tests passed!

[mraleph]

@thumbert this should be fixed on beta (upcoming stable).

So either try switching to beta or as an alternative workaround you can try the following:

1. In your Flutter SDK checkout in packages/flutter_tools/lib/src/test/runner.dart remove --chain-stack-traces line
2. Remove flutter tool snapshots (rm $(dirname $(which flutter))/cache/*.snapshot)

Then debugger should no longer stop inside http/IO internals.

[cpuell]

Same on my side.. was working in previous version and i updated recently to 3.13.9 and it appeared, as far as i can remember it was fixed in previous version already..

[thumbert]

@mraleph Confirming that your suggested "alternative workaround" fixes the issue. Thank you very much. Very useful.

[github-actions]

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 -v and a minimal reproduction of the issue.