Next 13 beta RCC fetch with useEffect not working with public directory

[TomasHubelbauer]

Verify canary release

• [X] 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 22.1.0: Sun Oct  9 20:14:54 PDT 2022; root:xnu-8792.41.9~2/RELEASE_X86_64
Binaries:
  Node: 19.0.0
  npm: 8.19.2
  Yarn: N/A
  pnpm: N/A
Relevant packages:
  next: 13.0.3-canary.3
  eslint-config-next: 13.0.2
  react: 18.2.0
  react-dom: 18.2.0

What browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

next export

Describe the Bug

I am using Next 13 beta with the app API (no pages routes) and I am hoping to build a component which pulls text from a TXT file in the public directory into its children. Here's the code:

'use client';

import Link from 'next/link';
import { useEffect, useState } from 'react';

export default function About() {
  const [text, setText] = useState('');
  useEffect(() => {
    void async function () {
      const response = await fetch('/rcc-useEffect-test.txt');
      const text = await response.text();
      setText(text);
    }()
  }, []);

  return (
    <>
      <header>
        <Link href="">« Home</Link>
      </header>
      {text}
    </>
  );
}

Unfortunately I am getting this error when I run next build && next export:

PageNotFoundError: Cannot find module for page: /rcc-useEffect-test

I am guessing next export is not fully upgraded to handle the app Next API yet?

Expected Behavior

I would expect Next to build and bundle the application for static file server (such as GitHub Pages) deployment.

Link to reproduction - Issues with a link to complete (but minimal) reproduction code will be addressed faster

https://github.com/TomasHubelbauer/next-13-ssg

To Reproduce

npm install
npm run build

Note that build is patched to be next build && next export so the error should come up.

[TomasHubelbauer]

Note, this issue is also happening when SSGing RSC route. See #42760 for details. In that case, the issue behaves a bit differently in that instead of the route path being reported as the issue, the main route / landing page path is actually being reported as problematic.