Is there a way to block subtasks from being create under an Epic?

[Matthew Oehler]

For hierarchical and other reasons we want Epic --> Issue (Task, Story, Bug) --> Sub-Task.  Unfortunetly new people always create Sub-tasks under an Epic, so I am looking for a way to block thar or even remove sub-tasks under Epic.

[Andy Heinzer]

There is an open feature request for this in https://jira.atlassian.com/browse/JRASERVER-7990

There is another post about this in https://community.atlassian.com/t5/Answers-Developer-Questions/How-to-Restrict-Creation-of-Subtask-based-on-IssueType-in-JIRA/qaq-p/525797

Some users have taken to generating a separate workflow for the subtask issue type to start with.  This isn't enough to limit their creation, but it does separate the changes to only effect those subtasks, and not all issue types.  From that point, there is a script that could be added to prevent this, but this would require the use of the scriptrunner plugin in JIRA.  In JIRA 7 the script needed would be something like

["Task", "Bug"].contains(issue.parentObject?.issueType.name)

You could then edit the create transition of that workflow and add a script validator (provided by scriptrunner), and enter this script.  That way you could limit which issue types can be used to create subtasks. 

[Matthew Oehler]

Thanks, I am now following the issue.  And will look into the script.