In middleware.js nextUrl.locale is always default for client-side routing if skipMiddlewareUrlNormalize is true

[matthewcc]

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
      Platform: darwin
      Arch: x64
      Version: Darwin Kernel Version 22.5.0: Mon Apr 24 20:51:50 PDT 2023; root:xnu-8796.121.2~5/RELEASE_X86_64
    Binaries:
      Node: 18.16.0
      npm: 9.5.1
      Yarn: 1.22.17
      pnpm: 8.1.0
    Relevant Packages:
      next: 13.4.13-canary.17
      eslint-config-next: 13.4.12
      react: 18.2.0
      react-dom: 18.2.0
      typescript: 5.1.6
    Next.js Config:
      output: N/A

Which area(s) of Next.js are affected? (leave empty if unsure)

Internationalization (i18n), Middleware / Edge (API routes, runtime), Routing (next/router, next/navigation, next/link)

Link to the code that reproduces this issue or a replay of the bug

https://github.com/matthewcc/middlware-test

To Reproduce

Clone the attached repo, or

• make a new project with create-nextjs-app.
• Add skipMiddlewareUrlNormalize: true to next.config.js
• add support for locales in the navigation and in next.config.js
• add middleware.js and log out req.nextUrl.locale

After cloning the attached repo or following the steps above, when doing client-side routing (NextLink or browser buttons) the value logged out for req.nextUrl.locale is always the default (in this case, "en-US").

This is using the classic Next.js setup, I do not know if the behavior is the same for app router or not.

Describe the Bug

If skipMiddlewareUrlNormalize: true is in next.config.js, then during client-side routing middleware.js's req.nextUrl.locale is always the default value even if the page is on another locale,

The string in req.nextUrl.pathname does contain the correct locale during client side routing, if skipMiddlewareUrlNormalize is set to true.

Expected Behavior

req.nextUrl.locale in middleware.js should always be accurate.

Which browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

Vercel

[github-actions]

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