Clone Issues or Parts of Issues in Jira

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.fields.CustomField

// the issue key of the issue to clone
final String originalIssueKey = "JRA-1"

// the summary of the new issue
final String newSummary = "A summary for the cloned issue"

// the empty map will clone all the custom fields from the original issue
final Map<CustomField, Optional<Boolean>> customFieldsToClone = [:]

final boolean cloneAttachments = true
final boolean cloneSubTasks = true
final boolean cloneLinks = true

def loggedInUser = ComponentAccessor.jiraAuthenticationContext.loggedInUser
def issueManager = ComponentAccessor.issueManager
def issueService = ComponentAccessor.issueService

def originalIssue = issueManager.getIssueByCurrentKey(originalIssueKey)

def validationResult = issueService.validateClone(loggedInUser, originalIssue, newSummary, cloneAttachments, cloneSubTasks, cloneLinks, customFieldsToClone)
assert validationResult.valid : validationResult.errorCollection

def result = issueService.clone(loggedInUser, validationResult)
assert result.valid : result.errorCollection