captureException during `next build` prerender fails cacheComponents routes (safe-random runner never registered in build workers)

[pnodet]

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/nextjs

SDK Version

10.57.0

Framework Version

Next.js 16.2.9 (cacheComponents: true)

Link to Sentry event

No response

Reproduction Example/SDK Setup

https://github.com/pnodet/next-prerender-random-repro — pnpm build fails on app/capture-metadata/page.tsx:

export const generateMetadata = (): Metadata => {
  // real-world pattern: report a recoverable data problem, return fallback metadata
  captureException(new Error('diagnostic: data missing for this page'));
  return { title: 'capture-metadata' };
};

Steps to Reproduce

1. pnpm install && pnpm build

Expected Result

The route prerenders; the event is dropped (no client at build) or buffered — either way the build succeeds. This is the same class as #21333, which was fixed for Date.now()/new Date() in v10.57.0 (#21351), but the crypto.randomUUID() path still fails at build time.

Root cause: uuid4() is correctly wrapped in withRandomSafeContext, but the runner under Symbol.for('__SENTRY_SAFE_RANDOM_ID_WRAPPER__') is only registered by prepareSafeIdGeneratorContext() inside init() — and next build prerender workers never load instrumentation.ts, so no runner exists there and crypto.randomUUID() runs unwrapped inside the prerender scope. (Observable in the repro: a tracer stashed on globalThis by register() is undefined during build prerendering.)

A possible fix: resolve the runner lazily per call instead of caching RESOLVED_RUNNER forever, and/or fall back to a fresh AsyncLocalStorage.snapshot() taken at @sentry/core module scope when no runner was registered.

Actual Result

Error: Route "/capture-metadata" used `crypto.randomUUID()` before accessing either uncached data (e.g. `fetch()`) or Request data (...). See more info here: https://nextjs.org/docs/messages/next-prerender-crypto
Error occurred prerendering page "/capture-metadata".
> Build error occurred

Also related (runtime side, filed against Next.js since the bug is in their tracer patch, but the trigger is @sentry/node's integrations): vercel/next.js#94753 — integration tracers are acquired in instrumentation constructors before initOpenTelemetry() registers the provider, so they are ProxyTracers whose getDelegateTracer() resolution bypasses Next's #82350 patch; OTel RandomIdGenerator Math.random() then fails every ISR revalidation of PPR routes that touch an instrumented resource (pg, undici, …). Sentry reports those as message-less Error: null (StaticGenBailoutError). You may want to track it, since it hits every @sentry/nextjs + cacheComponents app with a DB query in a prerendered shell — a defensive option on the SDK side would be re-acquiring instrumentation tracers after provider registration, or routing OTel id generation through the safe-random context.

[linear-code]

JS-2767

[logaretm]

Thanks for reporting this, we will take a look at it.

[chargome]

@pnodet as an immediate measure can you just guard your call like this:

if (Sentry.getClient()) {
  Sentry.captureException(ex)
}