What it does
Issue Subtask Types add-on enables you to define a mapping between parent issue type and it's subtask types and enforce user to select the type of subtask from the configured options only.
How I built it
It is classic JIRA Server add-on
Challenges I ran into
The trickiest part was to filter out "Issue Type" field of sub-task with the values from the mapping scheme
Accomplishments that I'm proud of
It took just one day to create this add-on due to previous experience with Issue Type Resolutions and Project Priorities add-ons.
What I learned
Different select type issue fields like "Issue Type", "Resolution" and "Priority" have completely different rendering logic )
What's next for Issue Subtask Types for JIRA
Currently the mapping between parent issue type and subtask types are global for all projects. I'm planning to enable mapping on a project basis.