[BUG] [Next 15] Dev/build error: Server Actions must be async functions

[monstajoe2002]

Are you using the latest version of this library?

• [X] I verified that the issue exists in the latest next-safe-action release

Is there an existing issue for this?

• [X] I have searched the existing issues and found nothing that matches

Describe the bug

I just upgraded to Next.js 15 and I got this at handleValidationErrorsShape: async (ev) => flattenValidationErrors(ev) saying that this has to be an async function. To mitigate this issue I added the async keyword. However, there's a race condition within next that I have to click the submit button twice to actually get back any validation errors

Reproduction steps

Upgrade to next Next 15 and use handleValidationErrorsShape on a server action

Expected behavior

No error at all

Link to a minimal reproduction of the issue

https://github.com/Caramella-Corner/caramellacorner.shop/blob/master/app/admin/_actions/products.ts

Operating System

Windows 11

Library version

7

Next.js version

15.0.1

Node.js version

20.18.0

Additional context

No response

[TheEdoRan]

Yep, unfortunately that's the current behavior of Next.js 15, not sure if it's a bug or expected, I'm waiting for an official reply by the Next.js team. Check out this tweet.