Problem Definition

At this moment, there is no field dependancy in Jira. The closest we have is the "Select List (cascading)" custom field, although it is a simple solution that add only multi level optioning.

Suggested Solution

Add the ability for admins to make a field required based on the value of other field.

Why this is important

This should enhance Jira's customization capabilities.

Workaround 

There is none.