Nextjs integration breaks module load completely in Web Worker, with "document is not defined"

[gthb]

• Review the documentation: https://docs.sentry.io/
• Search for existing issues: https://github.com/getsentry/sentry-javascript/issues
• Use the latest release: https://github.com/getsentry/sentry-javascript/releases
• Provide a link to the affected event from your Sentry account

Package + Version

• @sentry/browser
• @sentry/node
• raven-js
• raven-node (raven for node)
• other: @sentry/next

Version:

6.11.0

Description

Introducing a web worker into my app (which already has a @sentry/next integration), my worker module fails to load, saying document is not defined (because document does not exist in a Web Worker). I get this in the browser console, showing that the failure occurs in Sentry code which accesses document:

getVisibilityWatcher.js?84da:19 Uncaught ReferenceError: document is not defined
    at initHiddenTime (getVisibilityWatcher.js?84da:19)
    at getVisibilityWatcher (getVisibilityWatcher.js?84da:34)
    at getLCP (getLCP.js?00a4:23)
    at MetricsInstrumentation._trackLCP (metrics.js?b67e:235)
    at new MetricsInstrumentation (metrics.js?b67e:20)
    at new BrowserTracing (browsertracing.js?cc79:26)
    at eval (index.client.js?f3e4:25)
    at Module../node_modules/@sentry/nextjs/esm/index.client.js (src_engine_worker_js.js:972)
    at Module.options.factory (src_engine_worker_js.js:2562)
    at __webpack_require__ (src_engine_worker_js.js:2051)

Probably that LCP code (and I'm guessing some more of BrowserTracing) should not be called into at all, when executing in a web worker.

[gthb]

Seems like this hinges on MetricsInstrumentation neglecting to disable itself in a worker:

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

Lines 26 to 34 in 949f1b6

	if (!isNodeEnv() && global?.performance) {
	if (global.performance.mark) {
	global.performance.mark('sentry-tracing-init');
	}
	this._trackCLS();
	this._trackLCP();
	this._trackFID();
	}

... in a worker, global will be self, which does have the performance attribute, so this will try to instrument the worker for CLS and LCP and FID, which makes no sense (and fails, because that code reasonably assumes there's a document)

[AbhiPrasad]

Will be included with the next release, thanks for your help with the fix!