PPR: A required root parameter (locale) was not provided in generateStaticParams for /[locale]

[DiPSoMaNiE]

Description

Starting from next@15.1.1-canary.10 with experimental ppr enabled and use of setRequestLocale, I get the following error:

Error: A required root parameter (locale) was not provided in generateStaticParams for /[locale], please provide at least one value.

This error happened while generating the page. Any console logs will be displayed in the terminal window.
validateParams
node_modules/next/src/build/static-paths/app.ts (187:15)
validateParams
node_modules/next/src/build/static-paths/app.ts (512:7)

The error also occurs on next@15.1.1-canary.11 and next@15.1.1-canary.12 but everything works fine on next@15.1.1-canary.7.

Not knowing if it's a next-intl or a next issue, I'm reporting this in case it is an upcoming breaking change from next.

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/DiPSoMaNiE/next-intl-bug-repro-app-router

Reproduction description

Steps to reproduce:

1. Open reproduction
2. Run bun run dev (or install / run dev with another package manager)
3. Visit http://localhost:3000 and see error

Expected behaviour

Should not get any error.

[amannn]

Thanks for the report! I think that's related to the upcoming rootParams API, which should make setRequestLocale obsolete. I've got an experimental PR open here that explores these upcoming features: #1531. It's still a bit early with these APIs, I'm currently investigating how these can be adopted. I hopefully have more to share on this soon!

Have you tried adding generateStaticParams as mentioned in the error message?

[masterjanic]

Thanks for the report! I think that's related to the upcoming rootParams API, which should make setRequestLocale obsolete. I've got an experimental PR open here that explores these upcoming features: #1531. It's still a bit early with these APIs, I'm currently investigating how these can be adopted. I hopefully have more to share on this soon!

Have you tried adding generateStaticParams as mentioned in the error message?

I am experiencing the same issue on 15.1.1-canary.20, but I am not using setRequestLocale and I am using:

export function generateStaticParams() {
  return routing.locales.map((locale) => ({ locale }));
}

I have a nested layout like [locale]/some-path/[slug]. When trying to define generateStaticParams for the dynamic slug segment I get this error, but only if I have an empty array returned.

Should still be working IMO, so I guess it is a next bug. Let me know what you think!

[gijsbotje]

I ran into the same issue when trying PPR on my new project. Turns out I missed the static rendering section: https://next-intl.dev/docs/getting-started/app-router/with-i18n-routing#static-rendering
It explains adding the generateStaticParams and setRequestLocale that are necessary to get it working. After adding those, it works fine. @amannn hopefully the rootParams API will be released soon.

[github-actions]

This issue has been automatically closed because there was no recent activity and it was marked as unconfirmed. Note that issues are regularly checked and if they remain in unconfirmed state, they might miss information required to be actionable or are potentially out-of-scope. If you'd like to discuss this topic further, feel free to open a discussion instead.