getStaticPaths builds the wrong data files with [...params]

[stefanoverna]

Bug report

Describe the bug

With getStaticPaths, next build builds the wrong data files when using splat parameters [...params].

To Reproduce

Inside this route /foo/[...chunks]/index.js write the following:

export const unstable_getStaticPaths = async () => {
  return [
    { params: { chunks: ['a', 'b'] } },
  ]
}

export const unstable_getStaticProps = async ({ params: { chunks } }) => {
  // do stuff with chunks
}

// your page component

When running next build the data file created is:

_next/data/XXXX/foo/a%2Fb.json

while it should have been:

_next/data/XXXX/foo/a/b.json.

When browsing the site on ZEIT, the data file is ignored, and _next/data/XXXX/foo/a/b.json gets created instead.

System information

• Version of Next.js: 9.2.1

[ijjk]

Hi, this looks to be related to #10379 which is available in the latest canary of Next.js v9.2.3-canary.12

[stefanoverna]

Confirmed! Thanks @ijjk!

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.