Triggering notFound in generateMetadata results in Error: NEXT_NOT_FOUND when the delayed notFound call is used (e.g. fetch) about next.js HOT 1 CLOSED

Hi @fax1ty --

This doesn't appear to be related to where you call it -- ie, I see the same problem when I do the setTimeout + notFound() inside the Page component itself.

Can you clarify the real-world use-case a bit more? If you're trying to trigger notFound() after some async work, you should await that async work and call notFound() afterwards. For example:

const asyncWork = new Promise((resolve) => {
  setTimeout(() => {
    resolve();
  }, 500);
});

await asyncWork;
notFound();

When you call it inside of a setTimeout callback, Next.js won't be able to catch & handle the error, because it will happen asynchronously outside the main execution flow of your component. The notFound() function needs to be called within the lifecycle of a request in a way that Next.js can properly handle and render the appropriate error page.

In your original code, the notFound() function is being executed inside the setTimeout callback, which detaches it from the main request lifecycle. Next.js is designed to handle such errors synchronously within the request lifecycle. To fix this, ensure any asynchronous operations are properly awaited and errors like notFound() are called synchronously after those operations complete.

I'm going to close this as I don't think there's a bug, but please let me know if I'm misunderstanding a use-case that makes the above recommendation not possible.

from next.js.