_addTtfbRequestTimeToMeasurements throws TypeError: undefined is not an object (evaluating 't.responseStart')

[ilmarivacklinsc]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• 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/react

SDK Version

7.108.0

Framework Version

17.0.2

Link to Sentry event

https://supercell.sentry.io/issues/5105529056/events/84972ab28bc94b619f11d795c70f2bfe/?project=4504167659208704

SDK Setup

Sentry.init({
    maxValueLength: 3000,
    environment: buildInfo.environmentName,
    release: buildInfo.buildId,
    integrations: [
        browserTracingIntegration(),
        reactRouterV6BrowserTracingIntegration({
            useEffect,
            useLocation,
            useNavigationType,
            createRoutesFromChildren,
            matchRoutes,
        }),
        extraErrorDataIntegration(),
    ],
    tracesSampleRate: 0.1,
    sampleRate: 0.1,
    ...opts,
});

(opts includes the DSN)

Steps to Reproduce

Just used the web page. Note that this is coming from an iOS WKWebView.

Expected Result

The type of getNavigationEntry says it can return undefined, but _addTtfbRequestTimeToMeasurements doesn't check for this. I think this line should be changed:

sentry-javascript/packages/tracing-internal/src/browser/metrics/index.ts

Line 544 in ad02a79

const navEntry = getNavigationEntry() as TTFBMetric['entries'][number];

Actual Result

No accessing undefined.

[AbhiPrasad]

@ilmarivacklinsc good catch - we shouldn't be casting here. Opened fix with #11311

[AbhiPrasad]

Fix released with https://github.com/getsentry/sentry-javascript/releases/tag/7.109.0