Dynamic route does not parse params correctly when unencoded

[kudlajz]

Run next info (available from version 12.0.8 and up)

Operating System:
  Platform: darwin
  Arch: x64
  Version: Darwin Kernel Version 20.6.0: Wed Jun 23 00:26:31 PDT 2021; root:xnu-7195.141.2~5/RELEASE_X86_64
Binaries:
  Node: 17.1.0
  npm: 8.1.2
  Yarn: N/A
  pnpm: N/A
Relevant packages:
  next: 12.0.10
  react: 17.0.2
  react-dom: 17.0.2

What version of Next.js are you using?

12.0.10

What version of Node.js are you using?

17.1.0

What browser are you using?

Chrome

What operating system are you using?

macOS 11.5.2

How are you deploying your application?

next start

Describe the Bug

When using getServerSideProps, context.params is undefined when unencoded URL path is the same as the dynamic route's name.

Consider having a route called [slug].tsx.

If you access /[slug], context.params equals undefined ✖️
If you access /%5Bslug%5D, context.params equals { slug: '[slug]' } ✔️
If you access /foo[slug], context.params equals { slug: 'foo[slug]' } ✔️
If you access /[slug]foo, context.params equals { slug: '[slug]foo' } ✔️
If you access /[uuid], context.params equals { slug: '[uuid]' } ✔️

Minimal working example: https://github.com/kudlajz/nextjs-dynamic-route

Expected Behavior

For /[slug] URL path, context.params should be correctly defined as { slug: '[slug]' }

To Reproduce

1. Create a dynamic route, e.g. pages/[slug].tsx
2. Define getServerSideProps function
3. Access /[slug] in your application (make sure the brackets are not encoded)
4. Check value of context.params inside getServerSideProps

[balazsorban44]

Hi, this has been fixed on canary already (#33808), please upgrade or wait for the next latest release.

[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.