What causes "cron schedules must consist of 5 values only" in argoproj/argo-workflows?

Enter a standard 5-field cron expression (minute hour day-of-month month day-of-week).

cron schedules must consist of 5 values only

Error message

cron schedules must consist of 5 values only

What it means

ScheduleValidator checks user-entered cron schedules and throws the same error as PrettySchedule when the input has 6 or more space-separated values. The component only validates 5-field crons and shows a success icon via cronstrue otherwise; 6+ fields are rejected up front.

Source

Thrown at ui/src/cron-workflows/schedule-validator.tsx:9

import x from 'cronstrue';
import * as React from 'react';

import {SuccessIcon, WarningIcon} from '../shared/components/fa-icons';

export function ScheduleValidator({schedule}: {schedule: string}) {
    try {
        if (schedule.split(' ').length >= 6) {
            throw new Error('cron schedules must consist of 5 values only');
        }
        return (
            <span>
                <SuccessIcon /> {x.toString(schedule)}
            </span>
        );
    } catch (e) {
        return (
            <span>
                <WarningIcon /> Schedule maybe invalid: {e.toString()}
            </span>
        );
    }
}

View on GitHub (pinned to 35bff19146)

Solutions

Enter a standard 5-field cron expression (minute hour day-of-month month day-of-week).
Remove the seconds/year fields from a Quartz expression.
Catch the error in the validator and show a helpful message telling the user only 5-field crons are supported.

Example fix

// before
schedule: '0 30 9 * * ?'
// after
schedule: '30 9 * * *'

Defensive patterns

Strategy: validation

Validate before calling

const isValidCron = (s: string) => s.trim().split(/\s+/).length === 5;
if (!isValidCron(schedule)) showWarning('Use a 5-field cron expression');

Type guard

const isFiveFieldCron = (s: string): boolean =>
  s.trim().split(/\s+/).length === 5;

Try / catch

try {
  <ScheduleValidator schedule={schedule} />
} catch {
  <WarningIcon /> Only 5-field cron expressions are supported;
}

Prevention

Validate schedules on input in the cron-workflow form.
Strip seconds/year fields when importing Quartz crons.
Show inline validation before submission.

When it happens

Trigger: Typing a schedule in the cron-workflow form with 6+ fields, e.g. Quartz '0 30 9 * * ?' or '30 9 * * * 2026'.

Common situations: Copying Quartz/6-field crons from Java schedulers or crontab variants that include seconds or year fields; pasting with trailing whitespace.

Related errors

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/19f43ecd44aece9e. Report an issue: GitHub.