vavr-io/vavr

Hi @dfee,

Hi,

by looking at the implementation I don't see a problem with the internal use of the Exector at the moment (which does not necessarily mean there is none ;):

// Future.java

@Override
default <U> Future<U> map(Function<? super T, ? extends U> mapper) {
    Objects.requireNonNull(mapper, "mapper is null");
    return transformValue(t -> t.map(mapper));
}

default <U> Future<U> transformValue(Function<? super Try<T>, ? extends Try<? extends U>> f) {
    Objects.requireNonNull(f, "f is null");
    return run(executor(), complete ->
        onComplete(t -> Try.run(() -> complete.with(f.apply(t)))
                .onFailure(x -> complete.with(Try.failure(x)))
        )
    );
}

static <T> Future<T> run(Executor executor, Task<? extends T> task) {
    return FutureImpl.sync(executor, task);
}

// FutureImpl.java

static <T> FutureImpl<T> sync(Executor executor, Task<? extends T> task) {
    return new FutureImpl<>(executor, Option.none(), Queue.empty(), Queue.empty(), (complete, updateThread) ->
        task.run(complete::with)
    );
}

// constructor
private FutureImpl(Executor executor, Option<Try<T>> value, Queue<Consumer<Try<T>>> actions, Queue<Thread> waiters, Computation<T> computation) {
    this.executor = executor;
    synchronized (lock) {
        this.cancelled = false;
        this.value = value;
        this.actions = actions;
        this.waiters = waiters;
        try {
            computation.execute(this::tryComplete, this::updateThread);
        } catch (Throwable x) {
            tryComplete(Try.failure(x));
        }
    }
}

However, the Executor isn't respected when creating the CompletableFuture:

@Override
default CompletableFuture<T> toCompletableFuture() {
    final CompletableFuture<T> future = new CompletableFuture<>();
    onSuccess(future::complete);
    onFailure(future::completeExceptionally);
    return future;
}

That might be one problem. However, you also see problems during mapping a Future, right? Could you provide a minimal working example that does not use any 3rd library code?

Please create an issue if you think it is a bug. I could translate your example to Scala (which we align to) and see, how it behaves.