Bug report

Describe the bug

AsPath is incorrect on Server if you use rewrites and getInitialProps. On the server, asPath is the rewritten asPath while on the client asPath ist as given in the request URL.

To Reproduce

Start with a new next typescript project. And add:

Next.config.js

module.exports = {
  async rewrites() {
    return [
      {
        source: "/:sector(s1|s2)/product/:pid",
        destination: "/product/:pid",
      },
    ];
  },
};

/pages/product/[pid].tsx

import { NextPage } from 'next';
import { useRouter } from 'next/router';

const Product: NextPage = () => {
  const { asPath } = useRouter();
  console.log({ asPath });
  return <h1>Product</h1>;
};


Product.getInitialProps = ({ asPath, query }) => {
  // dataFetch
  return {};
};

export default Product;

1. Go to /s1/product/42
2. Compare logs on server and clientside.

Expected behavior

AsPath on server and client ist /s1/product/42

System information

• OS: Windows
• Version of Next.js: 10.0.3
• Version of Node.js: 12.18.3

Additional Information

If you use getServerSideProps instead of getInitialProps it works as expected. You can test this by replacing

Product.getInitialProps = ({ asPath, query }) => {
  // dataFetch
  return {};
};

with

export const getServerSideProps: GetServerSideProps = async () => {
  // datafetch
  return { props: {} };
};