workers-sdk: 🐛 BUG: wrangler2 can not decode `[` and `]`

What version of Wrangler are you using?

2.0.16

What operating system are you using?

Mac

Describe the Bug

Description

When I serve my next app statically with wrangler pages dev out, I believe wrangler is failing to decode [id] and throwing me a 404 error. When I examine the network tab of the developer console, I see that the failing request is to %5Bid%5D. However the same request results with a 200 response on Cloudflare Pages. Also if I edit the failing GET request by replacing the %5B and %5D with [ and ], I get a 200 response. I believe there is something wrong with the decoding of [ and ].

Steps to Reproduce

• Create a next app with yarn create next app pages-example
• Add "export": "next export" to package.json
• create a directory under /pages named p and create an empty [id].js file.
• fill the file with the following content

  import React  from 'react';
  import { useRouter } from 'next/router';
  
  const Page = () => {
      const router = useRouter();
  
      const { id } = router.query;
  
      console.log(id, router);
      return (
    	  <div>
    		  id from url: { id } 
    	  </div>
      );
  };
  
  export default Page;
  

• create a /functions/p/[id].js with the following content

  export function onRequestGet({ env, request, params }) {
    console.log("entering the function")
    console.log("env", env)
    console.log("request", request)
    return env.ASSETS.fetch(new Request(new URL('/p/[id]', request.url).toString(), request));
  }
  
  

• run yarn build && yarn export
• run wrangler pages dev out
• type http://localhost:8788/p/12 to the address bar.