NextJS 15's next/font breaks alternate header injection.

[zenzen-sol]

Description

I notice that in the NextJS 15 release candidate, the "alternate" links that should appear in the response header are missing if next/font is used to optimize fonts. I'm not sure whether this issue belongs to NextJS or next-intl.

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://github.com/zenzen-sol/next-reproduction-template/tree/sol/repro-001-next-15-broken

Reproduction description

Steps to reproduce:

1. Open reproduction
2. Run pnpm run dev
3. Reload http://localhost:3000 in a browser.
4. Check the response header links in dev tools.

✅ OK(Next 14): https://github.com/zenzen-sol/next-reproduction-template/tree/sol/repro-001-Next-14-working

---

🙅🏻Broken (Next 15rc + next/font): https://github.com/zenzen-sol/next-reproduction-template/tree/sol/repro-001-next-15-broken

---

✅ OK (Next 15rc without next/font): https://github.com/zenzen-sol/next-reproduction-template/tree/sol/repro-001-next-15-working

Expected behaviour

Both the next-intl and next/font links should be present in the response header.

[amannn]

Many thanks for the thoughtful bug report and reproduction! Do you think you could report this upstream in the Next.js repo? Seems like this is something to be addressed there. If you do, can you leave a link here so we can track the upstream issue?

[zenzen-sol]

@amannn Thanks. The upstream issue is here.

[amannn]

Thanks a lot, I'll keep an eye on the issue!

[A13k2]

Had a similar problem with nextjs 14. next/fonts would overwrite the first call to the document with the fonts.

This did not show up on local testing, just when deployed to vercel.

Our solution was to stop using next/fonts

[jefer94]

I was reporting this issue. you could reproduce this error with

1. Go to https://www.capyschool.com/en/reader the link header will be set by Next Font
2. Click in CapySchool, Link was set by Next Intl
3. Click on Learn, IPA Reader, the header will be set by Next Intl
4. Reload and the link header will be set by Next Font

What I am using? Next Font and Next Intl, I am not sure what library is doing the overwriting

localFont localFont

Mmmm it seems like a Next Font issue, I think that you set this header on Middleware and Next is overwriting it on page execution

[amannn]

There are currently two issues open for the same topic, I'll close this in favor of #1442. I noticed also next/image with priority causes the same error.