Need message to assign the defect on view issue details screen

[Garden16]

I am currently using a sub task (defect subtask) to manage defects.  Upon creating the create subtask link to create Sub task , a new a defect is created , I would like to assign the defect  to the developer using the Assign defect  button on the View issue detail screen.

I would like a  a warning message to be displayed  indicating the defect  needs to assigned on the  Issue view details page .

How Do I achieve this using script runner . Alternatively I would like to stop the open defect transition to be opened unless the defect  is assigned. I would like to display an error message if the developer clicks  on Open defect transition . 

I want to make sure that the defect  is not opened unless the defect  is assigned .Do not want it to be Un assigned .

Please suggest script runner solution for these issue .

[Tim Perrault]

Reread your question. I will need to think about the first part, but to stop the transition:

I think you will want to use a simple scripted validator on the transition in the workflow.

issue.assignee != null

Then you can put in the error message that you want.

[Tim Perrault]

For displaying a message you could create a custom script field and have that displayed on the view issue screen. The message would always be there, but I guess you could add a behaviour to hide it when someone has been assigned. Seems like overkill though.

I adapted something from this link https://scriptrunner.adaptavist.com/6.20.0/jira/recipes/scriptfields/informationMessage.html 

package com.onresolve.jira.groovy.test.scriptfields.scripts

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.Issue
import groovy.xml.MarkupBuilder
import com.atlassian.jira.config.properties.APKeys
StringWriter writer = new StringWriter()
MarkupBuilder builder = new MarkupBuilder(writer)

builder.div(class: "aui-message aui-message-error shadowed") {
p(class: "title") {
strong("Please make sure this issue has been assigned")
} 
}
return writer

[Garden16]

[Garden16]

Here is the screen shot of the view details screen