Issue Summary

This is reproducible on Data Center: yes

If you create an SLA with goals that uses a calendar which doesn't have any days selected, and you have sd.sla.improved.rendering feature flag turned on, the SLA will render in the issue view as an error:

This is because it uses the human readable version of the goal time, and this is calculated at run time, and it fails when the calendar has no days.

If you disable the sd.sla.improved.rendering feature flag, then it renders the regular goal time just fine. But in this edge case, it means the improved rendering is failing where the original isn't.

Steps to Reproduce

1. Ensure sd.sla.improved.rendering feature flag is enabled.
2. As a project admin, or Jira admin, navigate to a service project settings > SLAs > Calendars
3. Create a calendar with no days selected.
4. Create a new SLA with a variety of goals.
5. Set the goals to use the calendar created in step 1.
6. Create some customer support issues under the same project and view them.
7. SLA will render with an error.

Expected Results

• Calendars should require at least one day; or
• The non-human readable format should be used as a fallback; or
• This is a specifically identifiable edge case, where an "update calendar" recommendation could be displayed instead.

Actual Results

The improved SLA rendering fails to render the SLA as per the error image above.

Workaround

• Ensure that any calendar used on an SLA goal has at least one day selected