How to update subtask priority based on parent'a priority update?

[jgutierrez]

This is NOT when creating an issue. This is for editing. 

Let's say after a week after the issue was created. The parent issue's priority is changed from high to critical. Is it possible for an automation rule to update the subtask priority? 

[Bhanu]

You can build a script listener with the following code:

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.ModifiedValue
import com.atlassian.jira.issue.util.DefaultIssueChangeHolder
if(!event.issue.getSubTaskObjects()){ 
  return
}

def customFieldManager = ComponentAccessor.customFieldManager

if(event.issue.getSubTaskObjects()){ 

def subtasks = event.issue.getSubTaskObjects() 
def parentField = customFieldManager.getCustomFieldObjectByName("Your Parent Field's Name").getValue(event.issue) 

subtasks.each { 

def subtaskField = customFieldManager.getCustomFieldObjectByName("Your Subtask Field's Name") 

def changeHolder = new DefaultIssueChangeHolder() 

subtaskField.updateValue(null, it, new ModifiedValue(subtaskField.getValue(it), parentField), changeHolder) }}