Errors in generateMetadata are not handled by error.tsx

[codinginflow]

Often you need to fetch some data in generateMetadata:

export async function generateMetadata({ params: { username } }: PageProps): Promise<Metadata> {
    try {
        const user = await getUser(username);
        return {
            title: `${user.username} - Flow Blog`,
        };
    } catch (error) {
        if (error instanceof NotFoundError) {
            notFound();
        } else {
            throw error; 
        }
    }
}

The problem: The error we rethrow in the catch block doesn't lead to the error.tsx page. Instead, we get to a default full-screen error page that doesn't include any elements of our layout.tsx.

How am I supposed to make network requests in generateMetadata if errors are not handled properly?

[tom-sherman]

This really feels like a bug in Next.js.

[tom-sherman]

I feel strongly that this is a bug for dev mode so have raised it here #50863

[arjenbloemsma]

Hi @codinginflow,

To catch those errors you you need to add a 'global-error.tsx' to your app directory.

You can find more details in the nextjs docs here.

Hope this helps.

Kind regards,

Arjen

[codinginflow]

But I would like to catch the errors on the level of the page where they happen.

[tom-sherman]

I don't think that's possible, pretty sure generateMetadata runs in parallel across all route segments.

[codinginflow]

I don't think that's possible, pretty sure generateMetadata runs in parallel across all route segments.

What is the correct thing to do with errors in generateMetadata then? Should I return an empty object?

[tom-sherman]

That depends on your specific use case. Returning an empty object is probably a good first pass but in other cases you might want to return partial metadata in a best-effort manner.

[p00000001]

I have a similar issue with data fetching and calling notFound() from generateMetadata() that it skips the not-found.js page and defaults to global-error.js, I raised as an issue in #52329

I have worked around it by catching errors in generateMetadata() and returning blank metadata, and then the notFound() error throws again in the default page function.

However, I do agree that it seems more intuitive for generateMetadata() to handle errors in the same way as the default page function. This simplifies the code, and is likely a faster response because generateMetadata() typically returns first.

[hristokoev]

I'm now on Nextjs 15.0.0-canary.104 and this appears to be an ongoing issue. Errors from within the generateMetadata are not being redirected to the error.tsx that I've set up. Interestingly enough, on dev this works, but in production it doesn't.

[alvarlagerlof]

Please consider making a reproduction and open an issue. Considering #50863 was already resolved, I doubt anyone will look here unless there is a new issue opened.