Super class annotated with ITestNGListenerFactory makes derived test class throw TestNGException on execution

[RiJo]

TestNG Version

7.9.0

Expected behavior

No problems running test method in derived test class where ITestNGListenerFactory annotation is present on super class.

Actual behavior

TestNG crashes during load:

org.testng.TestNGException: Found more than one class implementing ITestNGListenerFactory:class com.test.MyTestNgFactory and class com.test.MyTestNgFactory
	at org.testng.internal.TestListenerHelper.lambda$findAllListeners$0(TestListenerHelper.java:149)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.testng.internal.TestListenerHelper.findAllListeners(TestListenerHelper.java:139)
	at org.testng.TestRunner.initListeners(TestRunner.java:374)
	at org.testng.TestRunner.init(TestRunner.java:357)
	at org.testng.TestRunner.init(TestRunner.java:307)
	at org.testng.TestRunner.<init>(TestRunner.java:182)
	at org.testng.SuiteRunner$DefaultTestRunnerFactory.newTestRunner(SuiteRunner.java:652)
	at org.testng.SuiteRunner.init(SuiteRunner.java:224)
	at org.testng.SuiteRunner.<init>(SuiteRunner.java:116)
	at org.testng.TestNG.createSuiteRunner(TestNG.java:1396)
	at org.testng.TestNG.createSuiteRunners(TestNG.java:1370)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1219)
	at org.testng.TestNG.runSuites(TestNG.java:1134)
	at org.testng.TestNG.run(TestNG.java:1101)
	at com.intellij.rt.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:66)
	at com.intellij.rt.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:105)

This is a regression in 7.9.0 as it was never seen in 7.8.0 or prior versions.

Is the issue reproducible on runner?

• Shell
• Maven
• Gradle
• Ant
• Eclipse
• IntelliJ
• NetBeans

Test case sample

Running ChildClass#test() throws exception above.

@Listeners(MyTestNgFactory.class)
public static class SuperClass {
}

public static class ChildClass extends SuperClass {
    @Test
    public void child() {
    }
}

public static class MyTestNgFactory implements ITestNGListener, ITestNGListenerFactory {
    @Override
    public ITestNGListener createListener(Class<? extends ITestNGListener> listenerClass) {
        return null;
    }
}

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[krmahadevan]

@RiJo - Thanks for logging this issue. The root cause of this problem was because of this #3002