KAFKA-8062: Do not remore StateListener when shutting down stream thread (#6468)

In a previous commit #6091, we've fixed a couple of edge cases and hence do not need to remove state listener anymore (before that we removed the state listener intentionally to avoid some race conditions, which has been gone for now).

Reviewers: Matthias J. Sax <mjsax@apache.org>,   Bill Bejeck <bbejeck@gmail.com>

streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java

@@ -191,7 +191,7 @@ public class KafkaStreams implements AutoCloseable {
      *   the instance will be in the ERROR state. The user will need to close it.
      */
     public enum State {
-        CREATED(1, 3), REBALANCING(2, 3, 5), RUNNING(1, 3, 5), PENDING_SHUTDOWN(4), NOT_RUNNING, ERROR(3, 5);
+        CREATED(1, 3), REBALANCING(2, 3, 5), RUNNING(1, 3, 5), PENDING_SHUTDOWN(4), NOT_RUNNING, ERROR(3);
 
         private final Set<Integer> validTransitions = new HashSet<>();
 
@@ -857,7 +857,6 @@ public class KafkaStreams implements AutoCloseable {
                 // notify all the threads to stop; avoid deadlocks by stopping any
                 // further state reports from the thread since we're shutting down
                 for (final StreamThread thread : threads) {
-                    thread.setStateListener(null);
                     thread.shutdown();
                 }
 
@@ -872,7 +871,6 @@ public class KafkaStreams implements AutoCloseable {
                 }
 
                 if (globalStreamThread != null) {
-                    globalStreamThread.setStateListener(null);
                     globalStreamThread.shutdown();
                 }
 

streams/src/main/java/org/apache/kafka/streams/processor/internals/StreamThread.java

@@ -269,7 +269,6 @@ public class StreamThread extends Thread {
             if (streamThread.assignmentErrorCode.get() == StreamsPartitionAssignor.Error.INCOMPLETE_SOURCE_TOPIC_METADATA.code()) {
                 log.error("Received error code {} - shutdown", streamThread.assignmentErrorCode.get());
                 streamThread.shutdown();
-                streamThread.setStateListener(null);
                 return;
             }
             final long start = time.milliseconds();

streams/src/test/java/org/apache/kafka/streams/KafkaStreamsTest.java

@@ -140,14 +140,14 @@ public class KafkaStreamsTest {
     }
 
     @Test
-    public void testStateCloseAfterCreate() {
+    public void stateShouldTransitToNotRunningIfCloseRightAfterCreated() {
         globalStreams.close();
 
         Assert.assertEquals(KafkaStreams.State.NOT_RUNNING, globalStreams.state());
     }
 
     @Test
-    public void testStateOneThreadDeadButRebalanceFinish() throws InterruptedException {
+    public void stateShouldTransitToRunningIfNonDeadThreadsBackToRunning() throws InterruptedException {
         final StateListenerStub stateListener = new StateListenerStub();
         globalStreams.setStateListener(stateListener);
 
@@ -171,7 +171,7 @@ public class KafkaStreamsTest {
         Assert.assertEquals(3, stateListener.numChanges);
         Assert.assertEquals(KafkaStreams.State.REBALANCING, globalStreams.state());
 
-        for (final StreamThread thread: globalStreams.threads) {
+        for (final StreamThread thread : globalStreams.threads) {
             thread.stateListener().onChange(
                 thread,
                 StreamThread.State.PARTITIONS_ASSIGNED,
@@ -194,7 +194,7 @@ public class KafkaStreamsTest {
         Assert.assertEquals(3, stateListener.numChanges);
         Assert.assertEquals(KafkaStreams.State.REBALANCING, globalStreams.state());
 
-        for (final StreamThread thread: globalStreams.threads) {
+        for (final StreamThread thread : globalStreams.threads) {
             if (thread != globalStreams.threads[NUM_THREADS - 1]) {
                 thread.stateListener().onChange(
                     thread,
@@ -214,6 +214,70 @@ public class KafkaStreamsTest {
         Assert.assertEquals(KafkaStreams.State.NOT_RUNNING, globalStreams.state());
     }
 
+    @Test
+    public void stateShouldTransitToErrorIfAllThreadsDead() throws InterruptedException {
+        final StateListenerStub stateListener = new StateListenerStub();
+        globalStreams.setStateListener(stateListener);
+
+        Assert.assertEquals(0, stateListener.numChanges);
+        Assert.assertEquals(KafkaStreams.State.CREATED, globalStreams.state());
+
+        globalStreams.start();
+
+        TestUtils.waitForCondition(
+            () -> stateListener.numChanges == 2,
+            "Streams never started.");
+        Assert.assertEquals(KafkaStreams.State.RUNNING, globalStreams.state());
+
+        for (final StreamThread thread : globalStreams.threads) {
+            thread.stateListener().onChange(
+                thread,
+                StreamThread.State.PARTITIONS_REVOKED,
+                StreamThread.State.RUNNING);
+        }
+
+        Assert.assertEquals(3, stateListener.numChanges);
+        Assert.assertEquals(KafkaStreams.State.REBALANCING, globalStreams.state());
+
+        globalStreams.threads[NUM_THREADS - 1].stateListener().onChange(
+            globalStreams.threads[NUM_THREADS - 1],
+            StreamThread.State.PENDING_SHUTDOWN,
+            StreamThread.State.PARTITIONS_REVOKED);
+
+        globalStreams.threads[NUM_THREADS - 1].stateListener().onChange(
+            globalStreams.threads[NUM_THREADS - 1],
+            StreamThread.State.DEAD,
+            StreamThread.State.PENDING_SHUTDOWN);
+
+        Assert.assertEquals(3, stateListener.numChanges);
+        Assert.assertEquals(KafkaStreams.State.REBALANCING, globalStreams.state());
+
+        for (final StreamThread thread : globalStreams.threads) {
+            if (thread != globalStreams.threads[NUM_THREADS - 1]) {
+                thread.stateListener().onChange(
+                    thread,
+                    StreamThread.State.PENDING_SHUTDOWN,
+                    StreamThread.State.PARTITIONS_REVOKED);
+
+                thread.stateListener().onChange(
+                    thread,
+                    StreamThread.State.DEAD,
+                    StreamThread.State.PENDING_SHUTDOWN);
+            }
+        }
+
+        Assert.assertEquals(4, stateListener.numChanges);
+        Assert.assertEquals(KafkaStreams.State.ERROR, globalStreams.state());
+
+        globalStreams.close();
+
+        // the state should not stuck with ERROR, but transit to NOT_RUNNING in the end
+        TestUtils.waitForCondition(
+            () -> stateListener.numChanges == 6,
+            "Streams never closed.");
+        Assert.assertEquals(KafkaStreams.State.NOT_RUNNING, globalStreams.state());
+    }
+
     @Test
     public void shouldCleanupResourcesOnCloseWithoutPreviousStart() throws Exception {
         builder.globalTable("anyTopic");