How to block the system not to create sub tasks if the subtasks are already existing

This article explains how to block the system not to create sub-tasks if the subtasks are already exists using the Create on Transition app.

Instructions

1. Add a post-function to the intended transition, to create a sub-task.
   To add a post-function, navigate to Cogwheel > Issues > Workflows > select the workflow of the project and edit the same.
2. Select Create Sub-task post function as shown below:
   
3. Select the Conditions & Configuration and add %jql_result_count% in Condition 1 and Regular expression pattern value as "0" by marking the Exact field under Conditions section:
   
   By using the %jql_result_count% and Regular expression pattern value as "0", it checks for the JQL query available under the Configuration section.
4. Add the value parent = %original_key% under the Configuration section in the JQL query.
   
   It checks whether the parent issue has sub-task(s) for the specific transition and creates a new sub-task(s) accordingly.
5. Click Update to save the settings. Verify the condition:
   
   
6. Publish the workflow draft.
7. Perform In Progress transition as shown. You will notice that issues are created based on the condition. If the transition repeats, it will not create any duplicate sub-tasks.