Jenkins pipeline java.io.NotSerializableException:groovy.util.slurpersupport.NodeChildren

我试图从Jenkinsfile（使用Groovy代码）运行管道作业，但出现以下错误-

java.io.NotSerializableException: groovy.util.slurpersupport.NodeChildren
    at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:860)
    at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:778)
    at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
    at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
    at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
    at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
    at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
    at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)
    at org.jboss.marshalling.MarshallerObjectOutputStream.writeObjectOverride(MarshallerObjectOutputStream.java:50)
    at org.jboss.marshalling.river.RiverObjectOutputStream.writeObjectOverride(RiverObjectOutputStream.java:179)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:344)
    at java.util.HashMap.internalWriteEntries(HashMap.java:1777)
    at java.util.HashMap.writeObject(HashMap.java:1354)
    at sun.reflect.GeneratedMethodAccessor101.invoke(Unknown Source)
...

我试图执行的代码是-

def getDataVersionFromNexus() {
    def user = params.nexusUser
    def password = params.nexusPassword    
    ...

    def oldVersion = -1
    print output
    if (!output.isEmpty()) {        
        def xmlContent = new XmlSlurper().parseText(output)
        oldVersion = "${xmlContent.versioning.release}"
    }

    return oldVersion
}

---

我曾尝试将该方法注释为

@NonCPS

（正如一篇类似的SO帖子中所建议的那样），但没有得到正确的输出。

尝试将该值作为列表复制到ArrayList，然后使用。 例如，像这样：

tmp = xmlContent.versioning.release.toList()
list = new ArrayList()
for (i = 0; i != tmp.size(); i += 1) {
    list.add(tmp.get(i))
}
oldVersion = list.get(0)

---

上面的问题不清楚是哪一行代码导致了这个问题。从错误来看，似乎是使用了XmlSlurper。堆栈跟踪显示在sun.reflect.GeneratedMethodAccessor101.invoke（未知源）