Enum exclude don't work properly from enum generated from protobuf

[jfrag]

Zod returned me this error message for an Enum with excluded params:

newStatus: Invalid option: expected one of "COMPLETED"|"CANCELLED"|0|1|2|3|4
The returned message normally was: newStatus: Invalid option: expected one of 0|1|2|3|4

The enum was generated from protobuf schema.

export enum SessionStatus {
    /**
     * @generated from protobuf enum value: SESSION_STATUS_UNSPECIFIED = 0;
     */
    UNSPECIFIED = 0,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_DRAFT = 1;
     */
    DRAFT = 1,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_OPEN = 2;
     */
    OPEN = 2,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_CONFIRMED = 3;
     */
    CONFIRMED = 3,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_IN_PROGRESS = 4;
     */
    IN_PROGRESS = 4,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_COMPLETED = 5;
     */
    COMPLETED = 5,
    /**
     * @generated from protobuf enum value: SESSION_STATUS_CANCELLED = 6;
     */
    CANCELLED = 6
}
export const SessionStatusSchema = z.enum(SessionStatus);
export const UpdateSessionStatusRequestSchema = z.object({
  sessionId: UUIDSchema,
  newStatus: SessionStatusSchema.exclude(['COMPLETED', 'CANCELLED'])
});

[pullfrog]

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[dosubot]

Hi @jfrag! I'm Dosu and I’m helping the zod team.

This happens because protobuf-generated TypeScript enums have both string keys (like "COMPLETED") and numeric values (like 5). When you pass the enum object directly to z.enum(), Zod tries to treat all the string keys as valid enum values, but the actual values are numbers. The .exclude() method only removes the named keys, not the numeric values, so both show up in error messages and validation logic. That's why you see both "COMPLETED", "CANCELLED" and the numbers in the error message, even after exclusion—Zod's enum handling is designed for string enums, not numeric ones like those from protobuf source.

In Zod v4, numeric enums are not directly supported by z.enum() anymore. The recommended approach is to use either a union of literals or a number schema with a refinement. For your case, you can do:

import { z } from "zod";
export enum SessionStatus {
  UNSPECIFIED = 0,
  DRAFT = 1,
  OPEN = 2,
  CONFIRMED = 3,
  IN_PROGRESS = 4,
  COMPLETED = 5,
  CANCELLED = 6
}

// Exclude COMPLETED (5) and CANCELLED (6)
const allowedStatuses = [
  SessionStatus.UNSPECIFIED,
  SessionStatus.DRAFT,
  SessionStatus.OPEN,
  SessionStatus.CONFIRMED,
  SessionStatus.IN_PROGRESS,
] as const;

const SessionStatusSchema = z.union(allowedStatuses.map(z.literal));

Or, using a refinement:

const allowedSet = new Set(allowedStatuses);
const SessionStatusSchema = z.number().refine(val => allowedSet.has(val), {
  message: "Invalid session status",
});

This will ensure only the numeric values you want are accepted, and error messages will only mention those numbers source.

If you need more help or a runnable reproduction, let me know your Zod version. If this solves your problem, please close the issue!

To reply, just mention @dosu.

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