Jira Post Functions Groovy Script Error

[Chan Young Jeong]

hi, All

If I select the "Select List (Multiple Choice)" field value
I want to automatically enter the USER ID in the "User Picker (Multiple Choice)" field.

ex)

Product (Multiple Select Field) - Smart FA  (Value)

                                                   TBD (Value)

                                                   Venus (Value)

People (Multiple User Choice Field)

If "Product" -> "Smart FA" is selected, I want to have UserID automatically input in the People Field.

So I wrote the following script.

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.CustomFieldManager
import com.atlassian.jira.ComponentManager
import com.atlassian.jira.issue.fields.CustomField
import com.atlassian.jira.issue.customfields.option.Option
import com.atlassian.jira.issue.ModifiedValue
import com.atlassian.jira.issue.util.DefaultIssueChangeHolder
import com.atlassian.jira.issue.util.IssueChangeHolder
import com.atlassian.jira.user.util.UserUtil

def componentManager = ComponentAccessor.getUserManager()
def customFieldManager = ComponentAccessor.getCustomFieldManager()

CustomField multi = customFieldManager.getCustomFieldObject("customfield_id" -> Product Field)
def options = issue.getCustomFieldValue(multi) as List<Option>

if (!options){
// No element is selected
}

if(options*.value.containsAll("Smart FA")) { 

CustomField person = customFieldManager.getCustomFieldObject("customfield_id" -> People Field)
IssueChangeHolder changeHolder = new DefaultIssueChangeHolder();
person.updateValue(null, issue, new ModifiedValue(issue.getCustomFieldValue(person), ["USER_ID"]), changeHolder)
}

However, the following error occurs.

java.lang.ClassCastException: java.lang.String cannot be cast to com.atlassian.jira.user.ApplicationUser
	at com.burningcode.jira.issue.customfields.impl.WatcherFieldType.getChangelogValue(WatcherFieldType.java:235)
	at com.burningcode.jira.issue.customfields.impl.WatcherFieldType.getChangelogValue(WatcherFieldType.java:80)
	at com.atlassian.jira.issue.fields.CustomFieldImpl.getChangelogValue(CustomFieldImpl.java:432)
	at com.atlassian.jira.issue.fields.CustomFieldImpl.updateValue(CustomFieldImpl.java:494)
	at com.atlassian.jira.issue.fields.CustomFieldImpl.updateValue(CustomFieldImpl.java:454)
	at com.atlassian.jira.issue.fields.OrderableField$updateValue.call(Unknown Source)
	at Script394.run(Script394.groovy:35)

What's wrong with Script?
Please help me.

thanks.

[Vasiliy Zverev · Accepted solution]

Here should be an Application user but not a String:

person.updateValue(null, issue, new ModifiedValue(issue.getCustomFieldValue(person),/*Here Application user is requred*/ ["USER_ID"]), changeHolder)

[Chan Young Jeong]

Thank you for answer.
It was helpful.