Refining adds error to "" instead of "root"

[mhuggins]

I'm using zod in conjunction with react-hook-form. (I don't think the use of react-hook-form is relevant, but I'm mentioning it just in case.) I have a simple schema defined as follows:

const schema = z
  .object({
    email: z.boolean(),
    slack: z.boolean(),
  })
  .refine(
    (input) => input.email || input.slack,
    { message: "At least one target is required" },
  );

When validation runs, the refinement error "At least one target is required" gets added to a key of "" instead of "root". If I log my errors object to the console, I see:

{
    "": {
        "message": "At least one integration target is required",
        "type": "custom"
    }
}

I'm expecting to see:

{
    "root": {
        "message": "At least one integration target is required",
        "type": "custom"
    }
}

I've tried specifying options for path: [] and path: ["root"] to refine, but neither seems to help. (The former results in the same thing, the latter results in an empty errors object.)