NextConfig is not correctly implemented

[sovetski]

Description

Hi,

I previously created a discussion for this, all related informations are there: #1683

On this issue I added the reproduction URL

Verifications

• I've verified that the problem I'm experiencing isn't covered in the docs.
• I've searched for similar, existing issues on GitHub and Stack Overflow.
• I've compared my app to a working example to look for differences.

Mandatory reproduction URL

https://codesandbox.io/p/github/sovetski/next-intl-bug-repro-app-router/main?import=true

Reproduction description

Steps to reproduce:

1. Go the URL that I provided (or clone from here: https://github.com/sovetski/next-intl-bug-repro-app-router)
2. The next-intl is disabled by default (commented), so go on yourlocaldomain/en/only-dev you will see that:

3. Now put back all next-intl code which are commented:

in next.config.ts:

comment export default nextConfig;

uncomment export default withNextIntl(nextConfig);

in layout.tsx:

uncomment all next-intl related part (there is 4-5 lines to uncomment not many)

uncomment next-intl related codes in page.tsx and only-dev/page.dev.tsx

4. Restart the dev environment

5. Try to go again yourlocaldomain/en/only-dev, now you will have 404 error

Expected behaviour

Nextjs config must work with or without next-intl. Next-intl should not impact inital Nextjs config

[amannn]

Hey, maybe we had a misunderstanding—this is not a bug. You need to pass a NextConfig to withNextIntl. In your example, nextConfig is not a NextConfig but a function that returns one.

You can fix it like this:

export default (phase: string) => {
  const nextConfig = {};
  return withNextIntl(nextConfig);
};

[sovetski]

Thank you @amannn you are right, it worked better with your suggestion, just before closing this issue let me try to reproduce it on the real project this evening, it will probably work too but who knows, I will come back to close it. Thank you again

[sovetski]

I confirm that it works as expected