1.x: fix Spsc queues reporting not empty but then poll() returns null

src/main/java/rx/internal/util/atomic/SpscAtomicArrayQueue.java

@@ -64,8 +64,8 @@ else if (null != lvElement(buffer, offset)){
                 return false;
             }
         }
-        soProducerIndex(index + 1); // ordered store -> atomic and ordered for size()
         soElement(buffer, offset, e); // StoreStore
+        soProducerIndex(index + 1); // ordered store -> atomic and ordered for size()
         return true;
     }
 
@@ -79,8 +79,8 @@ public E poll() {
         if (null == e) {
             return null;
         }
-        soConsumerIndex(index + 1); // ordered store -> atomic and ordered for size()
         soElement(lElementBuffer, offset, null);// StoreStore
+        soConsumerIndex(index + 1); // ordered store -> atomic and ordered for size()
         return e;
     }
 

src/main/java/rx/internal/util/atomic/SpscLinkedArrayQueue.java

@@ -90,8 +90,8 @@ public final boolean offer(final T e) {
     }
 
     private boolean writeToQueue(final AtomicReferenceArray<Object> buffer, final T e, final long index, final int offset) {
-        soProducerIndex(index + 1);// this ensures atomic write of long on 32bit platforms
         soElement(buffer, offset, e);// StoreStore
+        soProducerIndex(index + 1);// this ensures atomic write of long on 32bit platforms
         return true;
     }
 
@@ -101,11 +101,11 @@ private void resize(final AtomicReferenceArray<Object> oldBuffer, final long cur
         final AtomicReferenceArray<Object> newBuffer = new AtomicReferenceArray<Object>(capacity);
         producerBuffer = newBuffer;
         producerLookAhead = currIndex + mask - 1;
-        soProducerIndex(currIndex + 1);// this ensures correctness on 32bit platforms
         soElement(newBuffer, offset, e);// StoreStore
         soNext(oldBuffer, newBuffer);
         soElement(oldBuffer, offset, HAS_NEXT); // new buffer is visible after element is
                                                                  // inserted
+        soProducerIndex(currIndex + 1);// this ensures correctness on 32bit platforms
     }
 
     private void soNext(AtomicReferenceArray<Object> curr, AtomicReferenceArray<Object> next) {
@@ -131,8 +131,8 @@ public final T poll() {
         final Object e = lvElement(buffer, offset);// LoadLoad
         boolean isNextBuffer = e == HAS_NEXT;
         if (null != e && !isNextBuffer) {
-            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             soElement(buffer, offset, null);// StoreStore
+            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             return (T) e;
         } else if (isNextBuffer) {
             return newBufferPoll(lvNext(buffer), index, mask);
@@ -149,8 +149,8 @@ private T newBufferPoll(AtomicReferenceArray<Object> nextBuffer, final long inde
         if (null == n) {
             return null;
         } else {
-            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             soElement(nextBuffer, offsetInNew, null);// StoreStore
+            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             return n;
         }
     }
@@ -330,8 +330,8 @@ public boolean offer(T first, T second) {
         if (null == lvElement(buffer, pi)) {
             pi = calcWrappedOffset(p, m);
             soElement(buffer, pi + 1, second);
-            soProducerIndex(p + 2);
             soElement(buffer, pi, first);
+            soProducerIndex(p + 2);
         } else {
             final int capacity = buffer.length();
             final AtomicReferenceArray<Object> newBuffer = new AtomicReferenceArray<Object>(capacity);
@@ -342,9 +342,9 @@ public boolean offer(T first, T second) {
             soElement(newBuffer, pi, first);
             soNext(buffer, newBuffer);
 
-            soProducerIndex(p + 2);// this ensures correctness on 32bit platforms
-
             soElement(buffer, pi, HAS_NEXT); // new buffer is visible after element is
+
+            soProducerIndex(p + 2);// this ensures correctness on 32bit platforms
         }
 
         return true;

src/main/java/rx/internal/util/unsafe/SpscArrayQueue.java

@@ -110,8 +110,8 @@ public boolean offer(final E e) {
         if (null != lvElement(lElementBuffer, offset)){
             return false;
         }
-        soProducerIndex(index + 1); // ordered store -> atomic and ordered for size()
         soElement(lElementBuffer, offset, e); // StoreStore
+        soProducerIndex(index + 1); // ordered store -> atomic and ordered for size()
         return true;
     }
 
@@ -130,8 +130,8 @@ public E poll() {
         if (null == e) {
             return null;
         }
-        soConsumerIndex(index + 1); // ordered store -> atomic and ordered for size()
         soElement(lElementBuffer, offset, null);// StoreStore
+        soConsumerIndex(index + 1); // ordered store -> atomic and ordered for size()
         return e;
     }
 

src/main/java/rx/internal/util/unsafe/SpscUnboundedArrayQueue.java

@@ -132,8 +132,8 @@ public final boolean offer(final E e) {
     }
 
     private boolean writeToQueue(final E[] buffer, final E e, final long index, final long offset) {
-        soProducerIndex(index + 1);// this ensures atomic write of long on 32bit platforms
         soElement(buffer, offset, e);// StoreStore
+        soProducerIndex(index + 1);// this ensures atomic write of long on 32bit platforms
         return true;
     }
 
@@ -144,11 +144,11 @@ private void resize(final E[] oldBuffer, final long currIndex, final long offset
         final E[] newBuffer = (E[]) new Object[capacity];
         producerBuffer = newBuffer;
         producerLookAhead = currIndex + mask - 1;
-        soProducerIndex(currIndex + 1);// this ensures correctness on 32bit platforms
         soElement(newBuffer, offset, e);// StoreStore
         soNext(oldBuffer, newBuffer);
         soElement(oldBuffer, offset, HAS_NEXT); // new buffer is visible after element is
                                                                  // inserted
+        soProducerIndex(currIndex + 1);// this ensures correctness on 32bit platforms
     }
 
     private void soNext(E[] curr, E[] next) {
@@ -174,8 +174,8 @@ public final E poll() {
         final Object e = lvElement(buffer, offset);// LoadLoad
         boolean isNextBuffer = e == HAS_NEXT;
         if (null != e && !isNextBuffer) {
-            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             soElement(buffer, offset, null);// StoreStore
+            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             return (E) e;
         } else if (isNextBuffer) {
             return newBufferPoll(lvNext(buffer), index, mask);
@@ -192,8 +192,8 @@ private E newBufferPoll(E[] nextBuffer, final long index, final long mask) {
         if (null == n) {
             return null;
         } else {
-            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             soElement(nextBuffer, offsetInNew, null);// StoreStore
+            soConsumerIndex(index + 1);// this ensures correctness on 32bit platforms
             return n;
         }
     }

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

@@ -22,7 +22,7 @@
 import java.lang.ref.WeakReference;
 import java.util.*;
 import java.util.concurrent.*;
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.*;
 
 import org.junit.*;
 import org.mockito.InOrder;
@@ -32,6 +32,7 @@
 import rx.Observer;
 import rx.exceptions.*;
 import rx.functions.*;
+import rx.internal.util.UtilityFunctions;
 import rx.observers.TestSubscriber;
 import rx.schedulers.*;
 import rx.subjects.PublishSubject;
@@ -880,4 +881,30 @@ public void call(Throwable e) {
             }
         }
     }
+
+    @Test
+    public void asyncInner() throws Throwable {
+        for (int i = 0; i < 100; i++) {
+
+            final AtomicReference<Throwable> error = new AtomicReference<Throwable>();
+
+            Observable.just(Observable.range(1, 1000 * 1000).subscribeOn(Schedulers.computation()))
+            .switchMap(UtilityFunctions.<Observable<Integer>>identity())
+            .observeOn(Schedulers.computation())
+            .ignoreElements()
+            .timeout(5, TimeUnit.SECONDS)
+            .toBlocking()
+            .subscribe(Actions.empty(), new Action1<Throwable>() {
+                @Override
+                public void call(Throwable e) {
+                    error.set(e);
+                }
+            });
+
+            Throwable ex = error.get();
+            if (ex != null) {
+                throw ex;
+            }
+        }
+    }
 }