Sum All Story Points of Child Issues and Paste in Epic.groovy

// Get Story Points field ID
def storyPointsField = get("/rest/api/3/field")
    .asObject(List)
    .body
    .find { it.name == "Story Points" }
    .id

logger.info("Story Point ID : ${storyPointsField}")

// Cast issue.key to String
def eventIssue = Issues.getByKey(issue.key as String)
def issueType = eventIssue.issueType.name

if (issueType in ["Task", "Story", "Design Task"]) {
    def parentId = eventIssue.parentId
    if (!parentId) return

    // Fetch parent issue key
    def parentKey = get("/rest/api/3/issue/${parentId}")
        .queryString("fields", "key")
        .asObject(Map)
        .body
        .key

    // Initialize sum
def childTaskSum = 0.0  // use Double

Issues.search("parent = ${parentKey}").each { child ->
    // Avoid using the field ID that you retrived; use the field name directly
    def spValue = child.getCustomFieldValue('Story Points')
    def sp = spValue ? spValue.toString().toDouble() : 0
    childTaskSum += sp
}


  logger.info("Updating parent ${parentKey} with summed Story Points = ${childTaskSum}")
// Update the parent issue in one operation
put("/rest/api/3/issue/${parentKey}")
    .header("Content-Type", "application/json")
    .body([fields: [(storyPointsField): childTaskSum]])
    .asString()
}