Exception from ResourceManager at end of execution

[radeusgd]

Recently when running Enso I got:

Exception in thread "Thread-14" java.lang.IllegalStateException: Language environment is already disposed.
        at org.graalvm.truffle/com.oracle.truffle.api.TruffleLanguage$Env.checkDisposed(TruffleLanguage.java:1671)
        at org.graalvm.truffle/com.oracle.truffle.api.TruffleLanguage$Env.submitThreadLocalInternal(TruffleLanguage.java:3462)
        at org.graalvm.truffle/com.oracle.truffle.api.TruffleLanguage$Env.submitThreadLocal(TruffleLanguage.java:3435)
        at org.enso.interpreter.runtime.ResourceManager.scheduleFinalizationAtSafepoint(ResourceManager.java:122)
        at org.enso.interpreter.runtime.ResourceManager$Runner.run(ResourceManager.java:201)
        at java.base/java.lang.Thread.run(Thread.java:829)
        at org.graalvm.truffle/com.oracle.truffle.polyglot.SystemThread.run(SystemThread.java:65)

printed after all logs of my program.

The program exited with exit code 0, so it's not a big issue, but it may be a bit confusing.

The exception should probably be caught somewhere.

I'm not sure how I can repro it consistently but @JaroslavTulach said just the stacktrace will be sufficient for this report.

[JaroslavTulach]

Finalizers are executed asynchronously. In this situation we get a request to finalize something, but there is no longer any Context and Engine to run the finalization. I am afraid we will have to live with such a leak. We do force the finalizers that are pending, but we rely on JVM to tell us to "finalize" - such a request may arrive later, when the Context is already closed. Just like in htis case.

we could force the finalizers ignoring the fact that JVM did not 'yet' tell us

That is an option. But is it a good option? It basically implements Runtime.runFinalizersOnExit and that probably wasn't good idea: https://bugs.openjdk.org/browse/JDK-8198250. There is still Runtime.addShutdownHook - e.g. we could allow Managed_Resource register itself as "shutdown hook" and get a callback when the context is closing.

We can also invoke the "finalizers" when the context is closing too, but only if we have all the "finalizers" under control and we know that they are ready for such a premature (before things are GCed) invocation.

[JDK-8198250] Remove deprecated Runtime::runFinalizersOnExit and System::runFinalizersOnExit - Java Bug System

[JaroslavTulach]

I tried to reproduce problem in a #7302 test but it seems to be working fine. Does the exception still happen to you, @radeusgd?

I'm not sure how I can repro it consistently but @JaroslavTulach said just the stacktrace will be sufficient for this report.

I did, but I was wrong. The code in Runner & co. seem OKeyish. First of all it joins the Thread, sets isClosed = true and only then continues to GC the pending resources.

[radeusgd]

I tried to reproduce problem in a #7302 test but it seems to be working fine. Does the exception still happen to you, @radeusgd?

I haven't seen it for a while. It was very random to begin with, so it is hard to say. But I guess we can consider it non-reproducible and reopen if we encounter it again?