Using `wrapApiHandlerWithSentry` after upgrading to @sentry/nextjs 8.x results in API routes failing with TypeError

[AaronFriel]

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

8.15.0

Framework Version

Next 14.2.1

Link to Sentry event

n/a

SDK Setup/Reproduction Example

Install Sentry using @sentry/nextjs, and wrap an API route:

export const POST = wrapApiHandlerWithSentry(async (req: NextRequest): Promise<Response> => {
  // ...
}, "/my/route");

Steps to Reproduce

1. Call API route via fetch in the browser.

2. Observe:

   POST /my/route 500 in 17012ms
   ⨯ TypeError: Cannot create proxy with a non-object as target or handler
      at eval (webpack-internal:///(rsc)/../../node_modules/@sentry/nextjs/build/cjs/common/wrapApiHandlerWithSentry.js:78:29)
      at eval (webpack-internal:///(instrument)/../../node_modules/@sentry/node/node_modules/@sentry/opentelemetry/build/cjs/index.js:885:15)
      at Object.handleCallbackErrors (webpack-internal:///(instrument)/../../node_modules/@sentry/core/build/cjs/utils/handleCallbackErrors.js:26:26)
      at eval (webpack-internal:///(instrument)/../../node_modules/@sentry/node/node_modules/@sentry/opentelemetry/build/cjs/index.js:884:19)
   

Expected Result

Upgrading to @sentry/nextjs from 7.x to 8.x should not have resulted in 500 errors, especially after following the migration guide.

We previously used wrapApiHandlerWithSentry as Next.js 13 and 14 App Router route handlers were not automatically instrumented. The commit we added this call in linked to the tracking issue for App Router support, #6726. It looks like in upgrading our version of the Sentry SDK, this was fixed.

Actual Result

All API routes wrapped with wrapApiHandlerWithSentry return 500s and the type error above is thrown. It appears that this wrapping function and/or auto-instrumentation conflict.

This code appears relevant, but I'm not familiar with Sentry internals to say for sure:

sentry-javascript/packages/utils/src/object.ts

Lines 29 to 33 in 3549777

	// Make sure it's a function first, as we need to attach an empty prototype for `defineProperties` to work
	// otherwise it'll throw "TypeError: Object.defineProperties called on non-object"
	if (typeof wrapped === 'function') {
	markFunctionWrapped(wrapped, original);
	}

The error called out here is similar to the error we saw.

[lforst]

Hi, since you are using an App Router API route, you probably want to use wrapRouteHandlerWithSentry instead.

I opened a PR to make this more clear in the JSDoc.

[AaronFriel]

@lforst should the migration guide call this out? It was surprising to see it go from working in 7.x to causing 500 errors on those routes in 8.x.