mockito-inline: verify with timeout on synchronized method is causing deadlock

[brenuart]

The problem arises only when "inline mocking" is enabled (enabled as described in Mocking Final Types.)

Consider the following test case:

public static class MyService {
    public synchronized void execute() {
        System.out.println("Do something");
    }
}

@Test
public void test() {
    MyService service = spy(new MyService());

    Thread t = new Thread() {
        public void run() {
            try {
                // wait such that verify(service).execute() enters the method before us then invoke the service
                Thread.sleep(1000);
                service.execute();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    };
    t.start();

    verify(service, timeout(2000)).execute();
}

This test fails saying the execute() method has not been invoked before the timeout. After some investigations it appears that verify(service).execute() already holds a lock on the MyService instance preventing the async thread to access it.

On the other hand, everything works as expected when "inline mocking" is not enabled (test succeeds).
Is this scenario not supported ?
Can this be related to #2001 ?

Tested with Mockito 4.1.0 and OpenJDK 11.

[zhong2peng]

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[spmason]

Note that this seems to happen by default since the move to use mockito-inline in 5.0.0 (see #2001 (comment))