java.lang.IllegalMonitorStateException if thread is interrupted during NatsConnection.publish()

[davidmcote]

Observed behavior

My application uses thread interruption to signal that work should be aborted. When a thread is interrupted before making a call to anything that tries to publish a message to a NATS Connection, the call to publish throws an IllegalMonitorStateException.

Here's an example exception stack from a call to KeyValue.create().

java.lang.IllegalMonitorStateException(null)
java.lang.IllegalMonitorStateException
    at java.base/java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(ReentrantLock.java:175)
    at java.base/java.util.concurrent.locks.AbstractQueuedSynchronizer.release(AbstractQueuedSynchronizer.java:1007)
    at java.base/java.util.concurrent.locks.ReentrantLock.unlock(ReentrantLock.java:494)
    at io.nats.client.impl.MessageQueue.push(MessageQueue.java:187)
    at io.nats.client.impl.MessageQueue.push(MessageQueue.java:139)
    at io.nats.client.impl.NatsConnectionWriter.queue(NatsConnectionWriter.java:233)
    at io.nats.client.impl.NatsConnection.queueOutgoing(NatsConnection.java:1678)
    at io.nats.client.impl.NatsConnection.publishInternal(NatsConnection.java:990)
    at io.nats.client.impl.NatsConnection.requestFutureInternal(NatsConnection.java:1339)
    at io.nats.client.impl.NatsConnection.requestInternal(NatsConnection.java:1229)
    at io.nats.client.impl.NatsJetStreamImpl.makeInternalRequestResponseRequired(NatsJetStreamImpl.java:242)
    at io.nats.client.impl.NatsJetStream.publishSyncInternal(NatsJetStream.java:155)
    at io.nats.client.impl.NatsJetStream.publish(NatsJetStream.java:83)
    at io.nats.client.impl.NatsKeyValue._write(NatsKeyValue.java:238)
    at io.nats.client.impl.NatsKeyValue.update(NatsKeyValue.java:189)
    at io.nats.client.impl.NatsKeyValue.create(NatsKeyValue.java:168)

Expected behavior

Calls to NATS should either:

• (Strongly Preferred) Store the message into queueOutgoing and return successfully. Make no fuss about the calling thread being interrupted.
• Propagate a different exception out and restore the thread's interrupted flag.
• Propagate an InterruptedException out

Server and client version

Nats Server: 2.10.20
Nats Java client: 2.20.2

Host environment

Amazon Linux 2 within docker on c5a.2xlarge EC2 instance. Container limited to 2GiB RAM and 3vCPU.

Steps to reproduce

    @Test
    void testNatsIllegalStateMonitor() throws Exception {
        try (final Connection nc = Nats.connect()) {
            nc.publish("test", "test".getBytes()); // Successful

            Thread.currentThread().interrupt();

            nc.publish("test", "test".getBytes()); // throws java.lang.IllegalMonitorStateException
        }
    }