2.x Flowable.onErrorResumeNext() call is ambiguous when used with lambdas

[mostroverkhov]

Consider example

 Flowable.just(1).onErrorResumeNext(err -> Flowable.just(42));

In contrast to Observable 1.x and 2.x., this does not compile because both onErrorResumeNext(Function<Throwable, Publisher<T>> f) and onErrorResumeNext(Publisher<T> p) overloads fit, and has to be worked around with cast or introduction of method instead of lambda.

[akarnokd]

Hi. Unfortunately we can't rename either of the overloads at this point but can deprecate these and introduce two separate methods with distinct suffixes.

[JakeWharton]

You can also use `err -> { return Observable.just(42); }` which provides an indicator to the type inference of which overload you're using. Also I recently uninstalled Java 9, but it might be smart enough to infer this properly now.

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On Thu, Apr 20, 2017, 3:20 PM David Karnok ***@***.***> wrote: Hi. Unfortunately we can't rename either of the overloads at this point but can deprecate these and introduce two separate methods with distinct suffixes. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#5303 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAEEEbbAPFyMvxUwLC9v22414i0HSxPYks5rx74UgaJpZM4NDg1I> .

[mostroverkhov]

@JakeWharton That is helpful, simpler solution I have missed, thanks.
Regarding rename, how about introducing one onErrorResume(Function<Throwable, Publisher>), and deprecating both overloads - variant with Publisher alone appears less useful (one usually does not resume stream blindly w/o checking exception first)

[akarnokd]

Tried with 9b166 with IntelliJ 2017.1.2RC and javac is unable to disambiguate the expression form but works with the statement form:

Flowable.just(1)
        .onErrorResumeNext(v -> { return Flowable.just(2); });

Flowable.just(2)
        .onErrorResumeNext(o -> { o.onSubscribe(EmptySubscription.INSTANCE); });

This way, nothing has to change in RxJava 2 and we will re-evaluate naming in RxJava 3.

[mostroverkhov]

Anyway, proposed solution is good enough for me, closing

[rosasjose96]

You can also use err -> { return Observable.just(42); } which provides an indicator to the type inference of which overload you're using. Also I recently uninstalled Java 9, but it might be smart enough to infer this properly now.
…
On Thu, Apr 20, 2017, 3:20 PM David Karnok @.***> wrote: Hi. Unfortunately we can't rename either of the overloads at this point but can deprecate these and introduce two separate methods with distinct suffixes. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#5303 (comment)>, or mute the thread https://github.com/notifications/unsubscribe-auth/AAEEEbbAPFyMvxUwLC9v22414i0HSxPYks5rx74UgaJpZM4NDg1I .

The best solution, thnk!