How to set due date in jira issue automatically from version field release date?

Question

I have a custom field which allows selecting versions. From the selected version in the field, the release date should be extracted and that should be set as the due date for an issue created . (say newSubTask ). How to do that?

What I did was:

def versionCF = customFieldManager.getCustomFieldObjectByName("Fix Version(s)")

String valueOfversionType = parentIssue.getCustomFieldValue(versionCF)

Project project = parentIssue.getProjectObject()

Version versionn = versionManager.getVersion(project.getId(), valueOfversionType)

newSubTask.setDueDate(new Timestamp(versionn.releaseDate.time))

But I get the following error:

2016-11-23 10:18:10,909 ERROR [workflow.ScriptWorkflowFunction]: *************************************************************************************
2016-11-23 10:18:10,911 ERROR [workflow.ScriptWorkflowFunction]: Script function failed on issue: TPK-129, actionId: 1, file: <inline script>
java.lang.NullPointerException: Cannot invoke method getReleaseDate() on null object
	at Script1007.run(Script1007.groovy:61)

Vasiliy Zverev · Answer

* It is possible to make Fix version mandatory into field configuration
* Namely trouble is that versionn is null. It means that

versionManager.getVersion return null

Here is modified code

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.Issue
import com.atlassian.jira.issue.fields.CustomField
import com.atlassian.jira.project.version.Version

Issue parentIssue = null

CustomField versionCF = customFieldManager.getCustomFieldObjectByName("Fix Version(s)")

Version versionn = versionManager.getVersion(
        parentIssue.getParentObject().getProjectId()
        , parentIssue.getCustomFieldValue(versionCF))

if(versionn == null)
    return

newSubTask.setDueDate(new Timestamp(versionn.getReleaseDate().getTime()))

Shagufta Gurmuk · Answer

@Vasiliy Zverev can you help with that? with doing it through a custom field?

Shagufta Gurmuk · Answer

No, Fix Version/s is the built-in field, but i have created a custom field named Fix Version(s) since I had to make it mandatory in my project and making mandatory the built in field would have made it mandatory for all projects that use it.

So, basically, my field IS a custom field