[alibaba/arthas]stack命令可能会在 StackAdviceListener 抛出 NullPointerException

2021-01-21 18:54:39 [http-nio-7001-exec-33] WARN  c.t.a.c.c.m.StackAdviceListener -stack failed.
java.lang.NullPointerException: null
  at com.taobao.arthas.core.command.monitor200.StackAdviceListener.finishing(StackAdviceListener.java:67)
  at com.taobao.arthas.core.command.monitor200.StackAdviceListener.afterReturning(StackAdviceListener.java:52)
  at com.taobao.arthas.core.advisor.AdviceListenerAdapter.afterReturning(AdviceListenerAdapter.java:57)
  at com.taobao.arthas.core.advisor.SpyImpl.atExit(SpyImpl.java:67)
  at java.arthas.SpyAPI.atExit(SpyAPI.java:64)

原因是 com.taobao.arthas.core.command.monitor200.StackAdviceListener#stackThreadLocal

    private final ThreadLocal<StackModel> stackThreadLocal = new ThreadLocal<StackModel>();

    private void finishing(Advice advice) {
        // 本次调用的耗时
        try {
            double cost = threadLocalWatch.costInMillis();
            boolean conditionResult = isConditionMet(command.getConditionExpress(), advice, cost);
            if (this.isVerbose()) {
                process.write("Condition express: " + command.getConditionExpress() + " , result: " + conditionResult + "\n");
            }
            if (conditionResult) {
                // TODO: concurrency issues for process.write
                // TODO: should clear stackThreadLocal?
                StackModel stackModel = stackThreadLocal.get();
                stackModel.setTs(new Date());
                process.appendResult(stackModel);
                process.times().incrementAndGet();
                if (isLimitExceeded(command.getNumberOfLimit(), process.times().get())) {
                    abortProcess(process, command.getNumberOfLimit());
                }
            }