Use the 'Fields Required' workflow validator that is packaged in the JIRA Suite Utilities.
Please note the following caveats regarding validation of data by the 'Fields Required' workflow validator at the time of issue creation:
- fields that you set up as "required fields" are not flagged as such in the form to the end-user
- such fields can be cleared at a later time, which is not what you may have intended
- plugins such as GreenHopper will not detect the requirement as implemented by the workflow validator, so may fail later during usage
The reason 3rd party tools are needed is because JIRA's interpretation of "required" from a project's Field Configuration on some custom field means that the field is now required across all screens available to that project, regardless if the screen doesn't actually display that particular field. 3rd party tools, like the JIRA Suite Utilities' 'Fields Required' validator, are effectively a more granular means to control fields at the step or screen level at a project, instead of at the project level by the Project's Field Configuration.