Block `Close` Transition Until All Subtasks are Closed

Problem

We want to block the task 'Close' transition if there are subtasks which are not closed. To accomplish that we need to add a new condition to the 'Close' transition.

Solution

Adding a new condition

Log in as an administrator and navigate to Administration-> Workflows and edit "Close Issue" transition on the default JIRA workflow. Press `Add` a new condition:

Now add a '(k) SIL condition':

The following screen appears:

Writing code

The following code (also shown above) does all the magic:

//blocks `Close` transition on parent task
//until all its subtasks are closed
for (string sk in subtasks(key)) {     

    //if found subtask that has not been closed, return false     
    if (%sk%.status != "Closed") {         
        return false;     
    } 
}  

//otherwise return true 
return true;

Press the 'Save' button to save it on the server side (you can also check its syntax before, use the 'Check' button in the editor's menu).