Not working from Next.js middleware (edge runtime) when not using src folder

[pladaria]

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

1. npx create-next-app sentry-test. Create a new NextJS app with default values except the src directory (select No)

• ✔ Would you like to use src/ directory? … No

3. cd sentry-test. Enter to the directory
4. npx @sentry/wizard@latest -i nextjs. Run the sentry wizard
5. create a middleware.ts file (inside ./) that sends some traces to sentry, for example:

// ./middleware.ts
import {NextResponse} from 'next/server';
import * as Sentry from '@sentry/nextjs';

import type {NextRequest} from 'next/server';

export const middleware = (request: NextRequest): NextResponse => {
    Sentry.captureException(new Error('Sentry Example Middleware Error'));
    Sentry.captureMessage('Sentry Example Middleware Message', {
        level: 'info',
        extra: {
            method: request.method,
            path: request.nextUrl.pathname,
        },
    });
    console.log(request.method + ' ' + request.nextUrl.pathname);
    return NextResponse.next();
};

6. yarn dev. Run the dev server and open http://localhost:3000

Expected Result

Receive issues from the middleware

We can verify that the middleware gets executed by looking at the console.logs from the terminal

Actual Result

Not receiving issues from middleware

Product Area

Unknown

Link

No response

DSN

No response

Version

No response

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[getsantry]

Routing to @getsentry/product-owners-issues for triage ⏲️

[lforst]

Hi, can you try running a production build (next build && next start) instead of a dev build and try your setup? We generally design the SDK for production setups and some features (like edge runtime which middleware uses) are not available on dev for technical reasons.

[pladaria]

Hi, can you try running a production build (next build && next start) instead of a dev build and try your setup?

without src folder:

• dev build: not working
• prod build: not working

with src folder

same STR but selecting Yes when asked to use the src folder and storing the middleware.ts inside src

• dev build: working
• prod build: working

[lforst]

I unfortunately cannot reproduce this. On my Next.js 14 application without src folder and middleware.ts in the root of the project, events captured inside the middleware are successfully reported.

Can you please share a reproduction example? Either a github repo we can clone or a stackblitz or similar would be great. Thanks!

[pladaria]

Ok, I've created a repo, following the reported STR for each case:

https://github.com/pladaria/sentry-middleware-issue-reproduction-repo

There are two folders, with-src and without-src, each with a NextJS setup and a middleware.

After running both apps (dev and prod builds), I only get issues from the with-src project:

Verified that the middlewares are executed by looking at the console output logs

[lforst]

Thank you for the reproduction! You are indeed right and found a very stupid bug. We don't correctly detect the existence of the middleware.ts file if there is no pages folder. We will fix this.