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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    • 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)

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[✓] Connected device (2 available)
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    • Chrome (web)    • chrome • web-javascript • Google Chrome 122.0.6261.69

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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: https://github.com/flutter/flutter/issues/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