Catch-All path overrides Index path on the client

[ivan-kleshnin]

Bug report

Describe the bug

During the client-side navigation to /en URL which corresponds to pages/[lang]/index.js lambda

pages/[lang]/[...slugs].js is called with empty slugs instead of pages/[lang]/index.js.

It happens only in production mode (after Zeit builds). It also concerns only getServerSideProps triggered from the client-side navigation (clicks on Link).

The same code works fine with now build && now start and now dev on the local machine.

Probably related to: #10488

Expected behavior

pages/[locale]/index.js should always override pages/[locale]/[...catchAll].js route if both are present.

Demonstration

👉 Video proof: https://youtu.be/ZVwAj-TEWSI (~2 mins)

System information

Next 9.3
I didn't have this problem with Next 9.2

For the sake of completeness tried:

import NextLink from "next/link"

function TopMenu() {
  return <>
    <NextLink href="/[lang]" as="/en">
      <a>Home</a>
    </NextLink>

    <NextLink href="/[lang]/" as="/en/">
      <a>Home</a>
    </NextLink>
  </>
}

Both work fine on the local machine and both cause 500 error related to empty slugs in pages/[lang]/[...slugs].js in production.

[lachlanjc]

More activity/related: #19270

[ijjk]

Hi, this appears to be working correctly on the latest version of Next.js v10.0.5, as can be seen on this deployment https://test-index-mas20ojrb.vercel.app/ please update to the latest version and give it a try!

[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.