A StopActionException is be thrown by a task Action or task action closure to stop its own execution and to start execution of the task's next action. An action can usually be stopped by just calling return inside the action closure. But if the action works with helper methods that can lead to redundant code. For example:

     List existentSourceDirs = HelperUtil.getExistentSourceDirs()
     if (!existentSourceDirs) {return}
 

If the getExistentSourceDirs() throws a StopActionException instead, the tasks does not need the if statement.

Note that throwing this exception does not fail the execution of the task or the build.