Unhandled Promise Rejection in debugger on Node startup

[mwenko]

Is there an existing issue for this?

• [X] I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• [X] I have reviewed the documentation https://docs.sentry.io/
• [X] I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/node

SDK Version

8.7.0

Framework Version

8.7.0

Link to Sentry event

No response

SDK Setup

Sentry.init({
            dsn: dsn,
            environment: environmentWithAppInstance,
            debug: true,
            maxValueLength: maxValueLength,
            release: version,
            integrations: [nodeProfilingIntegration()],
            skipOpenTelemetrySetup: true,
            tracesSampler: (context) => {
                if (context.request?.url?.endsWith("/status")) {
                    return 0;
                }

                return defaultTraceSampleRate;
            },
            profilesSampleRate: profilesSampleRate,
            beforeBreadcrumb(breadcrumb, _) {
                if (!shouldAddBreadcrumb(breadcrumb)) {
                    return null;
                }

                return breadcrumb;
            },

            beforeSend(event: ErrorEvent, hint: Sentry.EventHint) {
                if (!shouldSend(hint)) {
                    return null;
                }

                event = removeAuthorizationHeader(event);

                return event;
            },
        });

Steps to Reproduce

1. Run nest start --debug --watch

Node: 20.9.0 NestJS: 10.3.8

Expected Result

The application should start without throwing an unhandled promise rejection.

Actual Result

It throws an unhandled promise rejection (see screenshot):

If I unmark "uncaught exception" in my editor it starts like expected.

[timfish]

This error isn't unhandled as it has a .catch(). You're likely hitting this in the debugger because you have Pause on caught exceptions enabled:

[mwenko]

This error isn't unhandled as it has a .catch(). You're likely hitting this in the debugger because you have Pause on caught exceptions enabled:

Thanks for the quick response.

If you look at the provided screenshot, you'll see that I have Uncaught Exception marked in the breakpoints section. (bottom left corner)

(I noticed that the code has a catch() applied. And it made the issue even weirder to me)

[timfish]

I think you're seeing this: https://github.com/microsoft/vscode/issues/116783

Which has a linked v8 dev tools issue which is still open: https://issues.chromium.org/issues/41161875

The argument is that debugger should not break here because the exception is later caught.

Without the debugger attached, this does not result in an unhandled promise rejection.

[timfish]

I've opened a PR in opentelemetry-instrumentation-fetch-node which should stop this from hitting the debugger issue.

[mwenko]

Hmm, I still experiencing this issue (using the latest release 8.17.0). The debugger stops because of an "unhandled promise rejection".

[AbhiPrasad]

I don't understand how this could be uncaught when there is a catch block right below it 🤔

Maybe this is because of how fetch internals work?

[mwenko]

I've opened a PR in opentelemetry-instrumentation-fetch-node which should stop this from hitting the debugger issue.

@timfish Did you test this PR if it resolves the issue?

[timfish]

@timfish Did you test this PR if it resolves the issue?

No sorry. I looked at the open Chromium debugger issues and the causes and then made assumptions based on that and what I know about how awaiting promises vs then work.

As @AbhiPrasad says above, the changes I made should have fixed this but the fact that it hasn't suggests this rejection is triggered by the fetch internals.

[mwenko]

@timfish

I opened a PR where the issue has been resolved in my project (running against 8.19 of Sentry)

https://github.com/gas-buddy/opentelemetry-instrumentation-fetch-node/pull/16

[timfish]

We're going to drop opentelemetry-instrumentation-fetch-node in favour of @opentelemetry/instrumentation-undici which should help solve this issue. I'll respond in this issue when this makes it into a release.

[mwenko]

We're going to drop opentelemetry-instrumentation-fetch-node in favour of @opentelemetry/instrumentation-undici which should help solve this issue. I'll respond in this issue when this makes it into a release.

Thank you for the update. I think it's a good decision to go with the official package.

[AbhiPrasad]

We've released https://github.com/getsentry/sentry-javascript/releases/tag/8.30.0 with using the official package.

[mwenko]

We've released https://github.com/getsentry/sentry-javascript/releases/tag/8.30.0 with using the official package.

Great work - it works!