Variable to collect assignees from sub-tasks, using lookupIssues not working

[isabel_p_cardoso_hotmail_com]

Could someone help me with variables and this lookup formula, please? I am new to advanced automation in Jira. I am trying to trigger this automation, everytime a sub-task changes assignee. The ideia is to have a variable that will store all assignees from the sub-tasks and then apply that to the story that is linked to those sub-tasks, but the variable does not seem to be collecting anything. 
Is it probably a sintaxt issue, but I have no idea what could be. Also, if possible, can someone advise me how I collect those names so that it does not repeat same assignees? Something like a distinct function? Thank you so much.

[Marc - Devoteam · Accepted solution]

Hi @isabel_p_cardoso_hotmail_com 

Try the following:

If an  issues is "Unassigned" no value will be shown in the log.

[isabel_p_cardoso_hotmail_com]

Thank you Marc. I was able to create a variable called {{resp}} and save the assignee names there but now I can't update the user story field Developers Assignee with the information in the variable {{resp}}.
I am stuck on the sub-task that triggered the action, which is the IP-16, and the error is that this issue does not have the field developers Assignee... which is right. Only the User story has this field.

Any ideas of what I am doing wrong?

[Marc - Devoteam]

Hi @isabel_p_cardoso_hotmail_com 

The rule I presented you triggers on a sub-task, then it finds the parent of the sub-task and the lookup finds all sub-tasks, based on the found parent.

[isabel_p_cardoso_hotmail_com]

Yeah.. I noticed that after not being able to add the variable into de parent issue (User story)... so I believe I need to start the branch with the branch : For Parent, but then the whole structure of lookups changes. I managed to do a lookup but got all the issues of my project (epics, user stories, sub-tasks)... I just can't seem to get a lookup formula that would get me only the sub-task of the parent issue.

[Duc Thang TRAN]

Hello @isabel_p_cardoso_hotmail_com 

I think using a lookup to check if the task has more than one subtask can display an error.

I suggest using this approach 

Best,