Not all errors are caught by Sentry on Flutter Web

[daniel-v]

Platform

Flutter Web

Obfuscation

Disabled

Debug Info

Disabled

Doctor

Flutter doctor

  
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    • Flutter version 3.19.1 on channel stable at /home/dvh/Documents/ThirdParty/flutter-3.19
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision abb292a07e (6 days ago), 2024-02-20 14:35:05 -0800
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    • Android SDK at /home/dvh/Android/Sdk
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      Run `path/to/sdkmanager --install "cmdline-tools;latest"`
      See https://developer.android.com/studio/command-line for more details.
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      Run `flutter doctor --android-licenses` to accept the SDK licenses.
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    • pkg-config version 1.9.5
    ✗ GTK 3.0 development libraries are required for Linux development.
      They are likely available from your distribution (e.g.: apt install libgtk-3-dev)

[✓] Android Studio (version 2023.1)
    • Android Studio at /home/dvh/Documents/ThirdParty/android-studio
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    • Java version OpenJDK Runtime Environment (build 17.0.7+0-17.0.7b1000.6-10550314)

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    • Flutter extension version 3.82.0

[✓] Connected device (2 available)
    • Linux (desktop) • linux  • linux-x64      • Fedora Linux 39 (KDE Plasma) 6.7.5-200.fc39.x86_64
    • Chrome (web)    • chrome • web-javascript • Google Chrome 122.0.6261.69

[✓] Network resources
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! Doctor found issues in 2 categories.

Version

7.16.1

Steps to Reproduce

Follow the instructions of setting Sentry up on its

1. package page OR
2. documentation page OR
3. the onboarding wizard of a new Sentry project

Expected Result

Callback errors such as the code sample below is caught by Sentry and reported.

 ElevatedButton(
  onPressed: () {
    throw StateError(
        'Sync callback errors are caught by FlutterError');
  },
  child: const Text('Sync callback error'),
)

Actual Result

Sentry does not capture the error and never reports it.

Are you willing to submit a PR?

Yes

[daniel-v]

A bit of clarification that did not fit in the previous comment by format:

This is verified only on Flutter Web. Other platforms are not tested.

I am not sure as to WHY this is happening, only that I observed this kind of behavior. As per the Flutter documentation, Sentry does what it should at first blick.

I did, however find a relevant SDK issue: flutter/flutter#129595

The easiest workaround I found was to also provide a FlutterError callback as seen here:

  var currentOnError = FlutterError.onError;
  FlutterError.onError = (details) {
    debugPrint('**** FlutterError.onError invoked for:');
    FlutterError.presentError(details);
    if (currentOnError != null) {
      currentOnError(details);
    }
  };

A quick win could be an update to docs, README and the onboarding wizard to let Flutter web users know about this?

[kahest]

Thank you @daniel-v, highly appreciated!

[buenaflor]

@daniel-v yeah documenting it sounds good, we have a flutter troubleshooting section at sentry-docs to which we can add the workaround