Unexpected behavior when a path parameter value matches the path parameter name

[klarstrup]

What version of Next.js are you using?

12.0.8-canary.6

What version of Node.js are you using?

whatever vercel.com is on

What browser are you using?

Chrome 97

What operating system are you using?

Windows

How are you deploying your application?

Vercel

Describe the Bug

For a URL like https://vercel.com/changelog/[item] to a page /changelog/[item].tsx, useRouter().query returns an empty object {}.

Expected Behavior

For a URL like https://vercel.com/changelog/[item] to a page /changelog/[item].tsx, one would expect useRouter().query to return { item: "[item]" }

To Reproduce

Request a path parameter's name as its value: https://vercel.com/changelog/[item]

[klarstrup]

https://vercel.com/support/articles/[slug] has also crashed on me

[balazsorban44]

Thanks, I could reproduce this locally with the following:

1. create page pages/[slug].js:

import { useRouter } from "next/router"

export default function Page() {
  const router = useRouter()
  return <pre>{JSON.stringify(router.query, null, 2)}</pre>
}

2. Visit http://localhost:3000/[slug]
3. Observe error in development
   

Just to investigate further, do you have a valid use case for this? 🤔

[klarstrup]

Just to investigate further, do you have a valid use case for this? 🤔

Not in particular, but errors from this behavior popped up in my production logs for access to a similar URL (may have come from bad internal URL building)

I decided to raise this issue since it's a case of unfortunate interpolation/escaping similar to the one I addressed in #31523

[klarstrup]

The main thing here is that it feels like a breach of API contract that there is a scenario where useRouter().query for a page /[param] will not have a string param property

I don't want to have to check for that in all of my dynamic routes :(

[balazsorban44]

I actually found this is a duplicate of #23824, so I'm going to close this issue in favor of the one that was reported earlier. Thank you for the investigation anyway, I'll backlink to this issue as well.

[github-actions]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.