OperatorAny needs to handle backpressure

rxjava-core/src/main/java/rx/internal/operators/OperatorAny.java

@@ -39,6 +39,7 @@ public Subscriber<? super T> call(final Subscriber<? super Boolean> child) {
         return new Subscriber<T>(child) {
             boolean hasElements;
             boolean done;
+
             @Override
             public void onNext(T t) {
                 hasElements = true;
@@ -48,6 +49,9 @@ public void onNext(T t) {
                     child.onNext(!returnOnEmpty);
                     child.onCompleted();
                     unsubscribe();
+                } else {
+                    // if we drop values we must replace them upstream as downstream won't receive and request more
+                    request(1);
                 }
             }
 
@@ -68,7 +72,7 @@ public void onCompleted() {
                     child.onCompleted();
                 }
             }
-            
+
         };
     }
 }

rxjava-core/src/test/java/rx/internal/operators/OperatorAnyTest.java

@@ -15,6 +15,7 @@
  */
 package rx.internal.operators;
 
+import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
@@ -27,6 +28,8 @@
 import rx.functions.Func1;
 import rx.functions.Functions;
 
+import java.util.Arrays;
+
 public class OperatorAnyTest {
 
     @Test
@@ -197,4 +200,16 @@ public Boolean call(Integer t1) {
         verify(observer, never()).onError(org.mockito.Matchers.any(Throwable.class));
         verify(observer, times(1)).onCompleted();
     }
+
+    @Test
+    public void testWithFollowingFirst() {
+        Observable<Integer> o = Observable.from(Arrays.asList(1, 3, 5, 6));
+        Observable<Boolean> anyEven = o.exists(new Func1<Integer, Boolean>() {
+            @Override
+            public Boolean call(Integer i) {
+                return i % 2 == 0;
+            }
+        });
+        assertTrue(anyEven.toBlocking().first());
+    }
 }