Visible directory structure on vercel instead of a 404

Bug report

Describe the bug

There is an inconsistency between the dev environment and vercel with the 404 page and the directory listing

On application that have a dynamic route /[locale]/foo. And staticly generate two routes: /fr/foo & /en/foo.

As expected, all the following urls are returning a 404 pages in development:

• ✔ /it/foo
• ✔ /fr/bar
• ✔ /fr
• ✔ /baz

On vercel environment the path /fr does not show a 404 pages but list the directory content.

• ✔ https://csb-gg6n3-4laukaxm8.vercel.app/it/foo
• ✔ https://csb-gg6n3-4laukaxm8.vercel.app/fr/bar
• ❌ https://csb-gg6n3-4laukaxm8.vercel.app/fr
• ✔ https://csb-gg6n3-4laukaxm8.vercel.app/baz

I’ve created a reproduction repository: https://github.com/Spy-Seth/nextjs-directory-listing-and-404-inconsistency

To Reproduce

You can use this codesandbox: https://codesandbox.io/s/focused-snyder-gg6n3

Expected behavior

I expect a 404 pages in all these cases.

System information

Version of Next.js: 9.5.2

[vajajak]

I’ve experienced the same exact issue today. Running Next.js 10.0.0. Fix this, pleeease!

[ijjk]

Hi, this should now be updated, please re-deploy your application and give it a try!