2.x: Improve coverage and fix small mistakes/untaken paths in operators (#5883)

Author: akarnokd

src/main/java/io/reactivex/Maybe.java

@@ -888,7 +888,7 @@ public static <T> Flowable<T> merge(Publisher<? extends MaybeSource<? extends T>
     public static <T> Flowable<T> merge(Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
         ObjectHelper.requireNonNull(sources, "source is null");
         ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
-        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, MaybeToPublisher.instance(), false, maxConcurrency, Flowable.bufferSize()));
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, MaybeToPublisher.instance(), false, maxConcurrency, 1));
     }
 
     /**
@@ -1222,12 +1222,11 @@ public static <T> Flowable<T> mergeDelayError(Iterable<? extends MaybeSource<? e
      *         {@code source} Publisher
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Flowable<T> mergeDelayError(Publisher<? extends MaybeSource<? extends T>> sources) {
-        return Flowable.fromPublisher(sources).flatMap((Function)MaybeToPublisher.instance(), true);
+        return mergeDelayError(sources, Integer.MAX_VALUE);
     }
 
 
@@ -1267,7 +1266,9 @@ public static <T> Flowable<T> mergeDelayError(Publisher<? extends MaybeSource<?
     @SchedulerSupport(SchedulerSupport.NONE)
     @Experimental
     public static <T> Flowable<T> mergeDelayError(Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
-        return Flowable.fromPublisher(sources).flatMap((Function)MaybeToPublisher.instance(), true, maxConcurrency);
+        ObjectHelper.requireNonNull(sources, "source is null");
+        ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, MaybeToPublisher.instance(), true, maxConcurrency, 1));
     }
 
     /**

src/main/java/io/reactivex/internal/operators/flowable/FlowableFlatMap.java

@@ -185,10 +185,10 @@ boolean addInner(InnerSubscriber<T, U> inner) {
         void removeInner(InnerSubscriber<T, U> inner) {
             for (;;) {
                 InnerSubscriber<?, ?>[] a = subscribers.get();
-                if (a == CANCELLED || a == EMPTY) {
+                int n = a.length;
+                if (n == 0) {
                     return;
                 }
-                int n = a.length;
                 int j = -1;
                 for (int i = 0; i < n; i++) {
                     if (a[i] == inner) {

src/main/java/io/reactivex/internal/operators/flowable/FlowableReduceSeedSingle.java

@@ -21,6 +21,7 @@
 import io.reactivex.functions.BiFunction;
 import io.reactivex.internal.functions.ObjectHelper;
 import io.reactivex.internal.subscriptions.SubscriptionHelper;
+import io.reactivex.plugins.RxJavaPlugins;
 
 /**
  * Reduce a sequence of values, starting from a seed value and by using
@@ -78,28 +79,36 @@ public void onSubscribe(Subscription s) {
         @Override
         public void onNext(T value) {
             R v = this.value;
-            try {
-                this.value = ObjectHelper.requireNonNull(reducer.apply(v, value), "The reducer returned a null value");
-            } catch (Throwable ex) {
-                Exceptions.throwIfFatal(ex);
-                s.cancel();
-                onError(ex);
+            if (v != null) {
+                try {
+                    this.value = ObjectHelper.requireNonNull(reducer.apply(v, value), "The reducer returned a null value");
+                } catch (Throwable ex) {
+                    Exceptions.throwIfFatal(ex);
+                    s.cancel();
+                    onError(ex);
+                }
             }
         }
 
         @Override
         public void onError(Throwable e) {
-            value = null;
-            s = SubscriptionHelper.CANCELLED;
-            actual.onError(e);
+            if (value != null) {
+                value = null;
+                s = SubscriptionHelper.CANCELLED;
+                actual.onError(e);
+            } else {
+                RxJavaPlugins.onError(e);
+            }
         }
 
         @Override
         public void onComplete() {
             R v = value;
-            value = null;
-            s = SubscriptionHelper.CANCELLED;
-            actual.onSuccess(v);
+            if (v != null) {
+                value = null;
+                s = SubscriptionHelper.CANCELLED;
+                actual.onSuccess(v);
+            }
         }
 
         @Override

src/main/java/io/reactivex/internal/operators/flowable/FlowableReplay.java

@@ -57,7 +57,7 @@ public final class FlowableReplay<T> extends ConnectableFlowable<T> implements H
     public static <U, R> Flowable<R> multicastSelector(
             final Callable<? extends ConnectableFlowable<U>> connectableFactory,
             final Function<? super Flowable<U>, ? extends Publisher<R>> selector) {
-        return Flowable.unsafeCreate(new MultiCastPublisher<R, U>(connectableFactory, selector));
+        return new MulticastFlowable<R, U>(connectableFactory, selector);
     }
 
     /**
@@ -1100,17 +1100,17 @@ Node getHead() {
         }
     }
 
-    static final class MultiCastPublisher<R, U> implements Publisher<R> {
+    static final class MulticastFlowable<R, U> extends Flowable<R> {
         private final Callable<? extends ConnectableFlowable<U>> connectableFactory;
         private final Function<? super Flowable<U>, ? extends Publisher<R>> selector;
 
-        MultiCastPublisher(Callable<? extends ConnectableFlowable<U>> connectableFactory, Function<? super Flowable<U>, ? extends Publisher<R>> selector) {
+        MulticastFlowable(Callable<? extends ConnectableFlowable<U>> connectableFactory, Function<? super Flowable<U>, ? extends Publisher<R>> selector) {
             this.connectableFactory = connectableFactory;
             this.selector = selector;
         }
 
         @Override
-        public void subscribe(Subscriber<? super R> child) {
+        protected void subscribeActual(Subscriber<? super R> child) {
             ConnectableFlowable<U> co;
             try {
                 co = ObjectHelper.requireNonNull(connectableFactory.call(), "The connectableFactory returned null");

src/main/java/io/reactivex/internal/operators/flowable/FlowableWindowBoundary.java

@@ -93,6 +93,7 @@ public void onSubscribe(Subscription s) {
                         produced(1);
                     }
                 } else {
+                    s.cancel();
                     a.onError(new MissingBackpressureException("Could not deliver first window due to lack of requests"));
                     return;
                 }
@@ -254,11 +255,6 @@ void next() {
             }
         }
 
-        @Override
-        public boolean accept(Subscriber<? super Flowable<T>> a, Object v) {
-            // not used by this operator
-            return false;
-        }
     }
 
     static final class WindowBoundaryInnerSubscriber<T, B> extends DisposableSubscriber<B> {

src/main/java/io/reactivex/internal/operators/flowable/FlowableWindowBoundarySelector.java

@@ -323,36 +323,22 @@ static final class WindowOperation<T, B> {
     static final class OperatorWindowBoundaryOpenSubscriber<T, B> extends DisposableSubscriber<B> {
         final WindowBoundaryMainSubscriber<T, B, ?> parent;
 
-        boolean done;
-
         OperatorWindowBoundaryOpenSubscriber(WindowBoundaryMainSubscriber<T, B, ?> parent) {
             this.parent = parent;
         }
 
         @Override
         public void onNext(B t) {
-            if (done) {
-                return;
-            }
             parent.open(t);
         }
 
         @Override
         public void onError(Throwable t) {
-            if (done) {
-                RxJavaPlugins.onError(t);
-                return;
-            }
-            done = true;
             parent.error(t);
         }
 
         @Override
         public void onComplete() {
-            if (done) {
-                return;
-            }
-            done = true;
             parent.onComplete();
         }
     }
@@ -370,12 +356,8 @@ static final class OperatorWindowBoundaryCloseSubscriber<T, V> extends Disposabl
 
         @Override
         public void onNext(V t) {
-            if (done) {
-                return;
-            }
-            done = true;
             cancel();
-            parent.close(this);
+            onComplete();
         }
 
         @Override

src/main/java/io/reactivex/internal/operators/flowable/FlowableWindowBoundarySupplier.java

@@ -326,7 +326,6 @@ public void onComplete() {
             }
             done = true;
             parent.onComplete();
-//            parent.next();
         }
     }
 }

src/main/java/io/reactivex/internal/operators/flowable/FlowableWindowTimed.java

@@ -390,9 +390,7 @@ public void onNext(T t) {
                             tm.dispose();
                             Disposable task = worker.schedulePeriodically(
                                     new ConsumerIndexHolder(producerIndex, this), timespan, timespan, unit);
-                            if (!timer.compareAndSet(tm, task)) {
-                                task.dispose();
-                            }
+                            timer.replace(task);
                         }
                     } else {
                         window = null;
@@ -549,9 +547,7 @@ void drainLoop() {
 
                                 Disposable task = worker.schedulePeriodically(
                                         new ConsumerIndexHolder(producerIndex, this), timespan, timespan, unit);
-                                if (!timer.compareAndSet(tm, task)) {
-                                    task.dispose();
-                                }
+                                timer.replace(task);
                             }
 
                         } else {

src/main/java/io/reactivex/internal/operators/observable/ObservableInternalHelper.java

@@ -199,24 +199,6 @@ public Object apply(Object t) throws Exception {
         }
     }
 
-    static final class RepeatWhenOuterHandler
-    implements Function<Observable<Notification<Object>>, ObservableSource<?>> {
-        private final Function<? super Observable<Object>, ? extends ObservableSource<?>> handler;
-
-        RepeatWhenOuterHandler(Function<? super Observable<Object>, ? extends ObservableSource<?>> handler) {
-            this.handler = handler;
-        }
-
-        @Override
-        public ObservableSource<?> apply(Observable<Notification<Object>> no) throws Exception {
-            return handler.apply(no.map(MapToInt.INSTANCE));
-        }
-    }
-
-    public static Function<Observable<Notification<Object>>, ObservableSource<?>> repeatWhenHandler(final Function<? super Observable<Object>, ? extends ObservableSource<?>> handler) {
-        return new RepeatWhenOuterHandler(handler);
-    }
-
     public static <T> Callable<ConnectableObservable<T>> replayCallable(final Observable<T> parent) {
         return new ReplayCallable<T>(parent);
     }
@@ -237,42 +219,6 @@ public static <T, R> Function<Observable<T>, ObservableSource<R>> replayFunction
         return new ReplayFunction<T, R>(selector, scheduler);
     }
 
-    enum ErrorMapperFilter implements Function<Notification<Object>, Throwable>, Predicate<Notification<Object>> {
-        INSTANCE;
-
-        @Override
-        public Throwable apply(Notification<Object> t) throws Exception {
-            return t.getError();
-        }
-
-        @Override
-        public boolean test(Notification<Object> t) throws Exception {
-            return t.isOnError();
-        }
-    }
-
-    static final class RetryWhenInner
-    implements Function<Observable<Notification<Object>>, ObservableSource<?>> {
-        private final Function<? super Observable<Throwable>, ? extends ObservableSource<?>> handler;
-
-        RetryWhenInner(
-                Function<? super Observable<Throwable>, ? extends ObservableSource<?>> handler) {
-            this.handler = handler;
-        }
-
-        @Override
-        public ObservableSource<?> apply(Observable<Notification<Object>> no) throws Exception {
-            Observable<Throwable> map = no
-                    .takeWhile(ErrorMapperFilter.INSTANCE)
-                    .map(ErrorMapperFilter.INSTANCE);
-            return handler.apply(map);
-        }
-    }
-
-    public static <T> Function<Observable<Notification<Object>>, ObservableSource<?>> retryWhenHandler(final Function<? super Observable<Throwable>, ? extends ObservableSource<?>> handler) {
-        return new RetryWhenInner(handler);
-    }
-
     static final class ZipIterableFunction<T, R>
     implements Function<List<ObservableSource<? extends T>>, ObservableSource<? extends R>> {
         private final Function<? super Object[], ? extends R> zipper;

src/main/java/io/reactivex/internal/operators/observable/ObservableReduceSeedSingle.java

@@ -89,8 +89,8 @@ public void onNext(T value) {
         @Override
         public void onError(Throwable e) {
             R v = value;
-            value = null;
             if (v != null) {
+                value = null;
                 actual.onError(e);
             } else {
                 RxJavaPlugins.onError(e);
@@ -100,8 +100,8 @@ public void onError(Throwable e) {
         @Override
         public void onComplete() {
             R v = value;
-            value = null;
             if (v != null) {
+                value = null;
                 actual.onSuccess(v);
             }
         }