throw SkipException in SuiteListener:onStart will hang start from 7.9.0

[sonwan2020]

We have lots of suites, and we use a centralized testng.xml with

Sometimes we want to skip some suites conditionally, so I add some logic in SuiteListener:onStart, and throw SkipException on some conditions.

Before release 7.8.0, this works.

But start from 7.9.0, there is a NPE error on thread, and the main job just hang there:

Exception in thread "TestNG-suites--1" java.lang.NullPointerException: Cannot invoke "org.testng.thread.IWorker.getTasks()" because "worker" is null
        at org.testng.internal.thread.graph.GraphOrchestrator.setStatus(GraphOrchestrator.java:119)
        at org.testng.internal.thread.graph.GraphOrchestrator.afterExecute(GraphOrchestrator.java:78)
        at org.testng.internal.thread.graph.TestNGFutureTask.done(TestNGFutureTask.java:34)
        at java.base/java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:381)
        at java.base/java.util.concurrent.FutureTask.setException(FutureTask.java:250)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:269)
        at org.testng.internal.thread.graph.TestNGFutureTask.run(TestNGFutureTask.java:22)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
        at java.base/java.lang.Thread.run(Thread.java:833)

What is the suggested way to skip a suite conditionally?

I have append a simple project to reproduce the failures.
just run mvn test in the project.

• if I set the testng version to 7.8.0, the behavior is expected: suite 2 run and finished, suite 1 skipped.
• If I set the testng version to 7.9.0, suite 2 run and finished, NPE on suite 1 and the command just hang there.
• same NPE and hang behavior with the latest 7.10.1

test.zip

[sonwan2020]

I implemented the interface IAlterSuiteListener, and clear the tests conditionally.
And the result is expected.