Transition Linked issue via Postfunction.groovy

def eventIssue = Issues.getByKey(issue.key as String)

// Construct JQL query
def jqlQuery = "issue in linkedIssues(\"${eventIssue.key}\") AND project = \"MTP\""

// Run search using the latest API
def searchResult = get("/rest/api/3/search/jql")
    .queryString("jql", jqlQuery)
    .queryString("fields", "summary,key,status")
    .queryString("maxResults", "50") // adjust as needed
    .asObject(Map)

if (searchResult.status == 200) {
    def issues = searchResult.body.issues

    issues.each { i ->
        def issueKey = i.key
        def statusName = i.fields.status.name

        logger.info("Issue ${issueKey} has status: ${statusName}")

        if (statusName == "Backlog") {
            // Direct transition using known ID 21
            def transitionResult = post("/rest/api/3/issue/${issueKey}/transitions")
                .header("Content-Type", "application/json")
                .body([
                    transition: [id: 21]
                ])
                .asString()

            if (transitionResult.status == 204) {
                logger.info("Successfully moved ${issueKey} to 'In Progress'.")
            } else {
                logger.error("Failed to transition ${issueKey}: HTTP ${transitionResult.status}")
            }
        }
    }
} else {
    logger.error("Failed to run JQL: ${searchResult.status} - ${searchResult.body}")
}