URL Casing Middleware Repro

Reproducing the issue where Next.js middleware receives URLs with pathnames already normalized to lowercase, preventing uppercase-to-lowercase redirects.

The Issue

When accessing /en-US, the middleware should receive the original casing to redirect to/en-us. However,req.url andreq.nextUrl.pathnamealready contain the lowercase version.

Test Links

Click these links and check the browser console + terminal for middleware logs:

/en-USUppercase locale /en-usLowercase locale /de-DEGerman uppercase /fr-FR/AboutNested path

Middleware Code

const lowercaseUrl = new URL(req.url);
const path = lowercaseUrl.pathname;

if (path !== path.toLowerCase()) {
  lowercaseUrl.pathname = path.toLowerCase();
  return NextResponse.redirect(lowercaseUrl.toString(), 308);
}

Check the terminal running the dev server to see the middleware logs.