Fix Take Early Unsubscription Causing Interrupts

Fixes ReactiveX#1804

Author: benjchristensen

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

@@ -63,13 +63,11 @@ public void onNext(T i) {
                 if (!isUnsubscribed()) {
                     if (++count >= limit) {
                         completed = true;
-                        // unsubscribe before emitting onNext so shutdown happens before possible effects
-                        // of onNext such as product.request(n) calls be sent upstream. 
-                        unsubscribe();
                     }
                     child.onNext(i);
                     if (completed) {
                         child.onCompleted();
+                        unsubscribe();
                     }
                 }
             }
@@ -83,11 +81,13 @@ public void setProducer(final Producer producer) {
 
                     @Override
                     public void request(long n) {
-                        long c = limit - count;
-                        if (n < c) {
-                            producer.request(n);
-                        } else {
-                            producer.request(c);
+                        if (!completed) {
+                            long c = limit - count;
+                            if (n < c) {
+                                producer.request(n);
+                            } else {
+                                producer.request(c);
+                            }
                         }
                     }
                 });

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

@@ -15,9 +15,7 @@
  */
 package rx.internal.operators;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.*;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Mockito.inOrder;
@@ -28,9 +26,11 @@
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import java.util.Arrays;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.junit.Test;
 import org.mockito.InOrder;
@@ -43,7 +43,6 @@
 import rx.Subscription;
 import rx.functions.Action1;
 import rx.functions.Func1;
-import rx.internal.operators.OperatorTake;
 import rx.observers.Subscribers;
 import rx.observers.TestSubscriber;
 import rx.schedulers.Schedulers;
@@ -365,4 +364,28 @@ public void request(long n) {
         }).take(1).subscribe(ts);
         assertEquals(1, requested.get());
     }
+    
+    @Test
+    public void testInterrupt() throws InterruptedException {
+        final AtomicReference<Object> exception = new AtomicReference<Object>();
+        final CountDownLatch latch = new CountDownLatch(1);
+        Observable.just(1).subscribeOn(Schedulers.computation()).take(1).subscribe(new Action1<Integer>() {
+
+            @Override
+            public void call(Integer t1) {
+                try {
+                    Thread.sleep(100);
+                } catch (Exception e) {
+                    exception.set(e);
+                    e.printStackTrace();
+                } finally {
+                    latch.countDown();
+                }
+            }
+
+        });
+
+        latch.await();
+        assertNull(exception.get());
+    }
 }