Merge pull request ReactiveX#1893 from akarnokd/MergeDelayErrorFix

Fixed incorrect error merging.

Author: benjchristensen

src/main/java/rx/internal/operators/OperatorMerge.java

@@ -307,7 +307,9 @@ private boolean drainQueuesIfNeeded() {
                     } finally {
                         boolean moreToDrain = releaseEmitLock();
                         // request outside of lock
-                        request(emitted);
+                        if (emitted > 0) {
+                            request(emitted);
+                        }
                         if (!moreToDrain) {
                             return true;
                         }
@@ -397,11 +399,13 @@ public Boolean call(InnerSubscriber<T> s) {
 
         @Override
         public void onError(Throwable e) {
-            completed = true;
-            innerError(e);
+            if (!completed) {
+                completed = true;
+                innerError(e, true);
+            }
         }
 
-        private void innerError(Throwable e) {
+        private void innerError(Throwable e, boolean parent) {
             if (delayErrors) {
                 synchronized (this) {
                     if (exceptions == null) {
@@ -411,7 +415,9 @@ private void innerError(Throwable e) {
                 exceptions.add(e);
                 boolean sendOnComplete = false;
                 synchronized (this) {
-                    wip--;
+                    if (!parent) {
+                        wip--;
+                    }
                     if ((wip == 0 && completed) || (wip < 0)) {
                         sendOnComplete = true;
                     }
@@ -520,6 +526,7 @@ private static final class InnerSubscriber<T> extends Subscriber<T> {
         final MergeSubscriber<T> parentSubscriber;
         final MergeProducer<T> producer;
         /** Make sure the inner termination events are delivered only once. */
+        @SuppressWarnings("unused")
         volatile int terminated;
         @SuppressWarnings("rawtypes")
         static final AtomicIntegerFieldUpdater<InnerSubscriber> ONCE_TERMINATED = AtomicIntegerFieldUpdater.newUpdater(InnerSubscriber.class, "terminated");
@@ -545,7 +552,7 @@ public void onNext(T t) {
         public void onError(Throwable e) {
             // it doesn't go through queues, it immediately onErrors and tears everything down
             if (ONCE_TERMINATED.compareAndSet(this, 0, 1)) {
-                parentSubscriber.innerError(e);
+                parentSubscriber.innerError(e, false);
             }
         }
 

src/test/java/rx/internal/operators/OperatorMergeDelayErrorTest.java

@@ -496,26 +496,32 @@ public void testErrorInParentObservable() {
 
     @Test
     public void testErrorInParentObservableDelayed() throws Exception {
-        final TestASynchronous1sDelayedObservable o1 = new TestASynchronous1sDelayedObservable();
-        final TestASynchronous1sDelayedObservable o2 = new TestASynchronous1sDelayedObservable();
-        Observable<Observable<String>> parentObservable = Observable.create(new Observable.OnSubscribe<Observable<String>>() {
-            @Override
-            public void call(Subscriber<? super Observable<String>> op) {
-                op.onNext(Observable.create(o1));
-                op.onNext(Observable.create(o2));
-                op.onError(new NullPointerException("throwing exception in parent"));
-            }
-        });
-
-        TestSubscriber<String> ts = new TestSubscriber<String>(stringObserver);
-        Observable<String> m = Observable.mergeDelayError(parentObservable);
-        m.subscribe(ts);
-        ts.awaitTerminalEvent(2000, TimeUnit.MILLISECONDS);
-        ts.assertTerminalEvent();
-
-        verify(stringObserver, times(2)).onNext("hello");
-        verify(stringObserver, times(1)).onError(any(NullPointerException.class));
-        verify(stringObserver, never()).onCompleted();
+        for (int i = 0; i < 50; i++) {
+            final TestASynchronous1sDelayedObservable o1 = new TestASynchronous1sDelayedObservable();
+            final TestASynchronous1sDelayedObservable o2 = new TestASynchronous1sDelayedObservable();
+            Observable<Observable<String>> parentObservable = Observable.create(new Observable.OnSubscribe<Observable<String>>() {
+                @Override
+                public void call(Subscriber<? super Observable<String>> op) {
+                    op.onNext(Observable.create(o1));
+                    op.onNext(Observable.create(o2));
+                    op.onError(new NullPointerException("throwing exception in parent"));
+                }
+            });
+    
+            @SuppressWarnings("unchecked")
+            Observer<String> stringObserver = mock(Observer.class);
+            
+            TestSubscriber<String> ts = new TestSubscriber<String>(stringObserver);
+            Observable<String> m = Observable.mergeDelayError(parentObservable);
+            m.subscribe(ts);
+            System.out.println("testErrorInParentObservableDelayed | " + i);
+            ts.awaitTerminalEvent(2000, TimeUnit.MILLISECONDS);
+            ts.assertTerminalEvent();
+    
+            verify(stringObserver, times(2)).onNext("hello");
+            verify(stringObserver, times(1)).onError(any(NullPointerException.class));
+            verify(stringObserver, never()).onCompleted();
+        }
     }
 
     private static class TestASynchronous1sDelayedObservable implements Observable.OnSubscribe<String> {

src/test/java/rx/internal/operators/OperatorObserveOnTest.java

@@ -609,47 +609,50 @@ public void testAsyncChild() {
 
     @Test
     public void testOnErrorCutsAheadOfOnNext() {
-        final PublishSubject<Long> subject = PublishSubject.create();
-
-        final AtomicLong counter = new AtomicLong();
-        TestSubscriber<Long> ts = new TestSubscriber<Long>(new Observer<Long>() {
-
-            @Override
-            public void onCompleted() {
-
-            }
-
-            @Override
-            public void onError(Throwable e) {
-
-            }
-
-            @Override
-            public void onNext(Long t) {
-                // simulate slow consumer to force backpressure failure
-                try {
-                    Thread.sleep(1);
-                } catch (InterruptedException e) {
+        for (int i = 0; i < 50; i++) {
+            final PublishSubject<Long> subject = PublishSubject.create();
+    
+            final AtomicLong counter = new AtomicLong();
+            TestSubscriber<Long> ts = new TestSubscriber<Long>(new Observer<Long>() {
+    
+                @Override
+                public void onCompleted() {
+    
+                }
+    
+                @Override
+                public void onError(Throwable e) {
+    
+                }
+    
+                @Override
+                public void onNext(Long t) {
+                    // simulate slow consumer to force backpressure failure
+                    try {
+                        Thread.sleep(1);
+                    } catch (InterruptedException e) {
+                    }
                 }
+    
+            });
+            subject.observeOn(Schedulers.computation()).subscribe(ts);
+    
+            // this will blow up with backpressure
+            while (counter.get() < 102400) {
+                subject.onNext(counter.get());
+                counter.incrementAndGet();
             }
-
-        });
-        subject.observeOn(Schedulers.computation()).subscribe(ts);
-
-        // this will blow up with backpressure
-        while (counter.get() < 102400) {
-            subject.onNext(counter.get());
-            counter.incrementAndGet();
+    
+            ts.awaitTerminalEvent();
+            assertEquals(1, ts.getOnErrorEvents().size());
+            assertTrue(ts.getOnErrorEvents().get(0) instanceof MissingBackpressureException);
+            // assert that the values are sequential, that cutting in didn't allow skipping some but emitting others.
+            // example [0, 1, 2] not [0, 1, 4]
+            List<Long> onNextEvents = ts.getOnNextEvents();
+            assertTrue(onNextEvents.isEmpty() || onNextEvents.size() == onNextEvents.get(onNextEvents.size() - 1) + 1);
+            // we should emit the error without emitting the full buffer size
+            assertTrue(onNextEvents.size() < RxRingBuffer.SIZE);
         }
-
-        ts.awaitTerminalEvent();
-        assertEquals(1, ts.getOnErrorEvents().size());
-        assertTrue(ts.getOnErrorEvents().get(0) instanceof MissingBackpressureException);
-        // assert that the values are sequential, that cutting in didn't allow skipping some but emitting others.
-        // example [0, 1, 2] not [0, 1, 4]
-        assertTrue(ts.getOnNextEvents().size() == ts.getOnNextEvents().get(ts.getOnNextEvents().size() - 1) + 1);
-        // we should emit the error without emitting the full buffer size
-        assertTrue(ts.getOnNextEvents().size() < RxRingBuffer.SIZE);
     }
 
     /**