Error when using .optional() with .refine() with Zod

[Ennoriel]

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Description
On a zod schema, when using .optional() with .refine(), the method superValidate(zod(schema) fails with error:

Async refinement encountered during synchronous parse operation. Use .parseAsync instead.

If applicable, a MRE

// file: +page.server.ts
import { superValidate } from "sveltekit-superforms/server";
import { zod } from "sveltekit-superforms/adapters";
import { z } from "zod";

const schema = z.object({
  name: z.string().min(1),
  email: z
    .string()
    .optional()
    .refine(async () => Promise.resolve(true)),
});

export const load = async () => {
  return { form: await superValidate(zod(schema)) };
};

// file: +page.svelte
// empty, not even implemented

[ciscoheat]

That is strange, since safeParseAsync is used in the adapter. Does it work when you remove optional?

[Ennoriel]

Thank you for your message :)

Yes, it works when removing .optional()

[ciscoheat]

It looks like a problem with Zod and the JSON Schema generator: colinhacks/zod#1460