sentry-javascript: Next.js Class extends value undefined is not a constructor or null on v7.89.0

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

7.89.0

Framework Version

7.89.0

Link to Sentry event

https://the-key.sentry.io/issues/4917806857/?project=4506501905252352&query=is%3Aunresolved&referrer=issue-stream&statsPeriod=14d&stream_index=0

SDK Setup

if (process.env.NODE_ENV === 'production') {
  nextConfig = withSentryConfig(
    nextConfig,
    {
      // For all available options, see:
      // https://github.com/getsentry/sentry-webpack-plugin#options

      // Suppresses source map uploading logs during build
      silent: true,
      org: 'my-org',
      project: 'my-app-nextjs',
    },
    {
      // For all available options, see:
      // https://docs.sentry.io/platforms/javascript/guides/nextjs/manual-setup/

      // Upload a larger set of source maps for prettier stack traces (increases build time)
      widenClientFileUpload: true,

      // Transpiles SDK to be compatible with IE11 (increases bundle size)
      transpileClientSDK: false,

      // Routes browser requests to Sentry through a Next.js rewrite to circumvent ad-blockers (increases server load)
      tunnelRoute: '/monitoring',

      // Hides source maps from generated client bundles
      hideSourceMaps: true,

      // Automatically tree-shake Sentry logger statements to reduce bundle size
      disableLogger: true,

      // Enables automatic instrumentation of Vercel Cron Monitors.
      // See the following for more information:
      // https://docs.sentry.io/product/crons/
      // https://vercel.com/docs/cron-jobs
      automaticVercelMonitors: false,
    }
  );
}

Steps to Reproduce

In my Next v14.1.0 app, I loaded a page, when a component seems to change inside the page, it caused an error from Sentry:

Class extends value undefined is not a constructor or null
This might be caused by a React Class Component being rendered in a Server Component, React Class Components only works in Client Components. Read more: https://nextjs.org/docs/messages/class-component-in-server-component

I have worked out the code that is the problem is within a server-only function which is loaded on every page to fetch user data from my API, this function is also where I am setting the user for Sentry.

import 'server-only';

import { cache } from 'react';
import { cookies } from 'next/headers';
import * as Sentry from '@sentry/nextjs';

/**
 * Fetch user's data
 * @returns {User | null}
 */
export const fetchUser = cache(async (): Promise<User | null> => {
  const res = await fetch(`${API_ENDPOINT}/keyusers/?current=True`, {
    headers: {
      Cookie: `sessionid=${cookies().get('sessionid')?.value}`,
      'Content-Type': 'application/json',
    },
  });
  
  if (!res.ok) {
    return null;
  }
  
  const data = await res.json();
  Sentry.setUser({ id: data.results[0].id });

  return data.results[0];
});

If I comment the Sentry parts out, everything works as expected.

This error doesn’t occur on v7.88.0 of @sentry/nextjs, so am stuck on this version for now. I use this function in several places within my monorepo, so am unable to upgrade Sentry until I can find a solution here.

Expected Result

No errors in the console to occur

Actual Result