Months in cron expression are rejected by validation

[k3rnL]

Pre-requisites

• I have double-checked my configuration
• I have tested with the :latest image tag (i.e. quay.io/argoproj/workflow-controller:latest) and can confirm the issue still exists on :latest. If not, I have explained why, in detail, in my description below.
• I have searched existing issues and could not find a match for this bug
• I'd like to contribute the fix myself (see contributing guide)

What happened? What did you expect to happen?

Hello,

I've just updated to the latest version, coming from v3, and I see a regression in the expression allowed in the cron scheduling.
Before I was using this expression : 00 8 3 Jan,Apr,Jul,Oct *
Which is valid and were working on the v3, this is a screenshot from the v3:

The validation of the workflow is rejected with this error:
Error: UPGRADE FAILED: cannot patch "density-map-quarterly" with kind CronWorkflow: CronWorkflow.argoproj.io "density-map-quarterly" is invalid: spec.schedules[0]: Invalid value: "00 8 3 Jan,Apr,Jul,Oct ": spec.schedules[0] in body should match '^(@(yearly|annually|monthly|weekly|daily|midnight|hourly)|@every\s+([0-9]+(ns|us|µs|ms|s|m|h))+|([0-9,/?-]+\s+){4}[0-9*,/?-]+)$'

Version(s)

v4.0.5

Paste a minimal workflow that reproduces the issue. We must be able to run the workflow; don't enter a workflow that uses private images.

apiVersion: argoproj.io/v1alpha1
kind: CronWorkflow
metadata:
  name: test
spec:
  schedules:
   - 00 8 3 Jan,Apr,Jul,Oct *
  timezone: UTC
  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 7
  failedJobsHistoryLimit: 7
  startingDeadlineSeconds: 0
  workflowSpec:
    entrypoint: date
    templates:
    - name: date
      container:
        image: alpine:3.23
        command: [sh, -c]
        args: ["date; sleep 90"]

Logs from the workflow controller

N/A

Logs from in your workflow's wait container

N/A

[partomatl]

Same with weekdays, had to switch to 0-6 (and 7) format 🙂