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

[DiPSoMaNiE]

Description

Starting from [email protected] 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 [email protected] and [email protected] but everything works fine on [email protected].

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.