`MockController` is not concurrency-friendly and leads to a deadlock

[boris-petrov]

Describe the bug

I've been debugging a random failure in one of my tests. It led me to the following stack-trace of a blocked thread:

      org.spockframework.mock.runtime.MockController.handle(MockController.java)
      org.spockframework.mock.runtime.JavaMockInterceptor.intercept(JavaMockInterceptor.java:86)
      org.spockframework.mock.runtime.ByteBuddyInterceptorAdapter.interceptNonAbstract(ByteBuddyInterceptorAdapter.java:35)
      ...

In my test basically I have a mock:

def latch = new CountDownLatch(1)
Mock(Foo) {
  get(1) >> {
    assert latch.await(5, TimeUnit.SECONDS)
  }
  get(2) >> {
    latch.countDown()
  }
}

And then I concurrently call get with 1 and with 2. If the thread that calls 1 gets to the await - the test fails. MockController.handle is a synchronized method and hence the second thread can't get in it (as the first one is in that method). Not sure if that's a known issue? If so, what's the workaround?

To Reproduce

See above.

Expected behavior

No deadlock.

Actual behavior

Deadlock.

Java version

21.0.2

Buildtool version

Gradle 8.6.

What operating system are you using

Linux

Dependencies

Just Spock.

Additional context

No response

[leonard84]

Duplicates #583

[boris-petrov]

Thanks. The other one is closed however? Not sure what that means - is it a "wontfix"?

[boris-petrov]

I'm in the process of converting our application to use virtual threads. Therefore I changed a bunch of places to use new threads. That now causes a lot of deadlocks in Spock in cases like the above or like a mocked object's method calling something else which in another thread calls back in the mocked object (but waiting for that thread to finish). I'm not really sure how to fix those unfortunately.

[AndreasTu]

The PR #1885 will fix both of the Tickets. See comment in the PR. I have corrected the state of #583.

[boris-petrov]

Awesome! Thank you very much for the great support as usual!

[boris-petrov]

Great, thanks for merging the fix! Do you have an ETA on a new release (even a beta)?

[leonard84]

@boris-petrov https://github.com/spockframework/spock/releases/tag/spock-2.4-M2 was released today