Custom routes and 404 on client side getServerSideProps access

Bug report

Describe the bug

I’m using custom routes to make translated paths (/hello, /hola, /ni-hao) for my server-side rendered pages (/hi/[lang].js). I then link to them like this:

<Link href="/hi/[lang]?lang=zh" as="/ni-hao">...</Link>

Unexpectedly though, a click on that link tries to load the data from getServerSideProps by requesting _next/data/.../ni-hao.json instead of _next/data/.../hi/[lang].json

To Reproduce

Repo: https://github.com/davidknezic/now-nextjs-issues/tree/now-nextjs-rewrites Live: https://now-nextjs-issues-git-now-nextjs-rewrites.davidknezic.vercel.app

next.config.js

module.exports = {
  target: 'serverless',
  experimental: {
    async rewrites () {
      return [
        { source: '/hello', destination: '/hi/en' },
        { source: '/hola', destination: '/hi/es' },
        { source: '/ni-hao', destination: '/hi/zh' }
      ]
    }
  }
}

pages/index.js

<Link href="/hi/[lang]?lang=zh" as="/ni-hao">
  <a>ni hao</a>
</Link>

pages/hi/[lang].js

export default function Index () {
  return (
    <h1>hi</h1>
  )
}

export async function getServerSideProps () {
  return {
    props: {}
  }
}

Expected behavior

I’d expect Next.js to fetch server side data based on the links href instead of the as param.

System information

• OS: any
• Browser: any
• Version of Next.js: 9.3.1

Additional context

I host all of this with Now, which currently doesn’t seem to understand Next.js rewrites, both in dev and productively. Is it planned to introduce this?

[davidknezic]

I was able to make it work by changing this._getServerData(as) to this._getServerData(pathname) in my local next.js repo:

https://github.com/zeit/next.js/blob/cadc950e2d2eea969ddabf135e9223b2c21108d6/packages/next/next-server/lib/router/router.ts#L618-L624

this._getStaticData(as) also uses the as param. However, there it might be on purpose.

[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.