Empty URL search params are swallowed when rewriting via middleware on Vercel

### Link to the code that reproduces this issue https://github.com/migueloller/vercel-middleware-search-params-bug-repro ### To Reproduce Deploy the application to Vercel. The easiest way is using the Vercel CLI. I have a deployed version that can be used to test [here](https://search-params-drab.vercel.app/?foo=bar). Visit the path `/?foo=` and then visit `/?foo=bar`. Note that while the search params are there for `/?foo=bar`, they are not there for `/?foo=`. ### Current vs. Expected behavior The expectation is that URL search params are there even if the value is an empty string. Note, this is only happening because of the rewrite in the middleware. If the `middleware.ts` file is deleted, then the expected behavior occurs. ### Provide environment information ```bash Operating System: Platform: darwin Arch: arm64 Version: Darwin Kernel Version 23.6.0: Mon Jul 29 21:13:04 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T6020 Available memory (MB): 16384 Available CPU cores: 10 Binaries: Node: 18.19.0 npm: 10.2.3 Yarn: 1.22.21 pnpm: 8.15.6 Relevant Packages: next: 15.0.3 // There is a newer version (15.0.4) available, upgrade recommended! eslint-config-next: 15.0.3 react: 19.0.0-rc-66855b96-20241106 react-dom: 19.0.0-rc-66855b96-20241106 typescript: 5.7.2 Next.js Config: output: N/A ⚠ There is a newer version (15.0.4) available, upgrade recommended! Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue. Read more - https://nextjs.org/docs/messages/opening-an-issue ``` ### Which area(s) are affected? (Select all that apply) Middleware ### Which stage(s) are affected? (Select all that apply) Vercel (Deployed) ### Additional context The issue only happens when deploying to Vercel, it does not reproduce during local development. This is likely due to differences in the runtime middleware runs on in Vercel vs local dev.