Error when using robots.txt and sitemap.xml as route handlers in appDir

[Fredkiss3]

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
Platform: linux
Arch: x64
Version: Ubuntu 20.04.0 LTS Wed Feb 15 2023 15:52:38 GMT+0100 (Central European Standard Time)
Binaries:
Node: 16.14.2
npm: 7.17.0
Yarn: 1.22.19
pnpm: 7.13.6
Relevant packages:
next: 13.1.7-canary.15
eslint-config-next: N/A
react: 18.2.0
react-dom: 18.2.0

Which area(s) of Next.js are affected? (leave empty if unsure)

App directory (appDir: true), Middleware / Edge (API routes, runtime)

Link to the code that reproduces this issue

https://stackblitz.com/edit/github-t3cgzq

To Reproduce

Run the project, then click on one of links. When returning back you'll be met with an unknown error
You could also move the folders robots.txt and sitemap.xml and run the next build It will give this error :

TypeError: Cannot read properties of undefined (reading '')

TypeError: Cannot read properties of undefined (reading '')
    at Va (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1205:56)
    at Ma (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1335:50)
    at Array.toJSON (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1066:32)
    at stringify ()
    at Ua (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1393:53)
    at Qa (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1185:35)
    at ping (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1194:32)
TypeError: Cannot read properties of undefined (reading '')
    at Va (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1205:56)
    at Ma (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1335:50)
    at Object.toJSON (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1066:32)
    at stringify ()
    at Ua (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1393:53)
    at Qa (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1185:35)
    at ping (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1194:32)
TypeError: Cannot read properties of undefined (reading '')
    at Va (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1205:56)
    at Ma (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1335:50)
    at Array.toJSON (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1066:32)
    at stringify ()
    at Ua (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1393:53)
    at Qa (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1185:35)
    at ping (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1194:32)
TypeError: Cannot read properties of undefined (reading '')
    at Va (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1205:56)
    at Ma (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1335:50)
    at Array.toJSON (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1066:32)
    at stringify ()
    at Ua (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1393:53)
    at Qa (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1185:35)
    at ping (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1194:32)

Error occurred prerendering page "/". Read more: https://nextjs.org/docs/messages/prerender-error
TypeError: Cannot read properties of undefined (reading '')
    at Va (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1205:56)
    at Ma (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1335:50)
    at Array.toJSON (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1066:32)
    at stringify ()
    at Ua (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1393:53)
    at Qa (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1185:35)
    at ping (file:///home/projects/github-t3cgzq/.next/server/chunks/869.js:1194:32)

Describe the Bug

When using robots.txt/route.ts or sitemap.xml/route.ts next give an error in dev and in build.

One weird thing is that if we move these files into (goup)/robots.txt/route.ts and (goup)/sitemap.xml/route.ts, in dev it will give us an error but on prod, it will work fine.

It seems like there is a conflict between the metadata generation and these routes.

Expected Behavior

next should not throw an error when using robots.txt or sitemap.xml as route handlers, if this is a legit error, then. maybe throw a more descriptive error.

Which browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

[karlhorky]

This seems to be similar to the bug reported by @Josehower :

• [NEXT-588] fetch to App Route + router.refresh() causes crash #45956

[Fredkiss3]

It has been fixed in the latest canary 13.2.2-canary.2.

[github-actions]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.