2.x: Fix & prevent null checks on primitives (#6014)

Author: akarnokd

src/main/java/io/reactivex/Observable.java

@@ -1455,8 +1455,6 @@ public static <T> Observable<T> concatEager(ObservableSource<? extends Observabl
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Observable<T> concatEager(ObservableSource<? extends ObservableSource<? extends T>> sources, int maxConcurrency, int prefetch) {
-        ObjectHelper.requireNonNull(maxConcurrency, "maxConcurrency is null");
-        ObjectHelper.requireNonNull(prefetch, "prefetch is null");
         return wrap(sources).concatMapEager((Function)Functions.identity(), maxConcurrency, prefetch);
     }
 
@@ -1507,8 +1505,6 @@ public static <T> Observable<T> concatEager(Iterable<? extends ObservableSource<
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Observable<T> concatEager(Iterable<? extends ObservableSource<? extends T>> sources, int maxConcurrency, int prefetch) {
-        ObjectHelper.requireNonNull(maxConcurrency, "maxConcurrency is null");
-        ObjectHelper.requireNonNull(prefetch, "prefetch is null");
         return fromIterable(sources).concatMapEagerDelayError((Function)Functions.identity(), maxConcurrency, prefetch, false);
     }
 

src/main/java/io/reactivex/internal/functions/ObjectHelper.java

@@ -128,4 +128,17 @@ public boolean test(Object o1, Object o2) {
             return ObjectHelper.equals(o1, o2);
         }
     }
+
+    /**
+     * Trap null-check attempts on primitives.
+     * @param value the value to check
+     * @param message the message to print
+     * @return the value
+     * @deprecated this method should not be used as there is no need
+     * to check primitives for nullness.
+     */
+    @Deprecated
+    public static long requireNonNull(long value, String message) {
+        throw new InternalError("Null check on a primitive: " + message);
+    }
 }

src/test/java/io/reactivex/internal/functions/ObjectHelperTest.java

@@ -65,4 +65,10 @@ public void compareLong() {
         assertEquals(0, ObjectHelper.compare(0L, 0L));
         assertEquals(1, ObjectHelper.compare(2L, 0L));
     }
+
+    @SuppressWarnings("deprecation")
+    @Test(expected = InternalError.class)
+    public void requireNonNullPrimitive() {
+        ObjectHelper.requireNonNull(0, "value");
+    }
 }

src/test/java/io/reactivex/internal/operators/flowable/FlowableCreateTest.java

@@ -934,6 +934,7 @@ public void subscribe(FlowableEmitter<Object> e) throws Exception {
         }
     }
 
+    @SuppressWarnings("rawtypes")
     @Test
     public void emittersHasToString() {
         Map<BackpressureStrategy, Class<? extends FlowableEmitter>> emitterMap =