When clone operation on subtask by parent issue fails at create transition, there is no reaction to user

Summary

When trying to clone a subtask by cloning its parent issue fails at some validation step, then a cloned issue gets created but without any subtask. In addition to it, there is no message shown up to notify user about that failure at all.

There are two possible solutions for this bug as you can see in Expected Results section as below. The purpose of reporting this bug are to keep tracking in bug list and wait for feedback from ohernandez@atlassian.com to decide which way to go.

Steps to reproduce

1. Create a validator such as Required Fields (*Affects Version/s* for instance) by using JIRA Test Suites
2. Create an issue and then a subtask for that newly created issue.
3. Edit the subtask to remove *Affects Version/s*.
4. Try to clone above issue with checking Clone subtasks.

Expected Results

The issue as well as its subtasks do not create a clone at all and notifies user the reason.

Actual Results

The issue gets cloned without any subtask as well as notification.

Solution

We first check whether the issue including its all subtasks are able to be cloned, if not, we cancel the clone operation and explain user the problem.
Involved classes: CloneIssueDetails.java, CreateIssue.java, and CreateIssueDetails.java