doOnDispose() vs doOnUnsubscribe()

[julioromano]

While migrating some code from 1.2.x to 2.0 I've noticed a difference:

• 1.2.x : Observable.doOnUnsubscribe() is always called whenever an observable chain terminates, either because it's been explicitly terminated with Subscription.unsubscribe() or because onComplete() or onError() have been called.
  This is the way I usually used to insert side effects on chain termination.

• 2.x : there is no Observable.doOnUnsubscribe() so I've resorted using Observable.doOnDispose() instead but this one is called only when explicitly terminating an observable chain with Disposable.dispose();

I'm assuming this difference is intended (i.e. not a bug) so how can we 'insert' side effects on chain termination with RxJava 2.0?

[akarnokd]

In 1.x, the SafeSubscriber always called unsubscribe on a terminal event and that triggered doOnUnsubscribe. In 2.x, the lifecycle is now different and the upstream is considered disposed/cancelled upon receiving a terminal event. Therefore, unless you explicitly call dispose, the doOnDispose won't execute.

The general way of making sure a resource is disposed on completion, error or cancellation, you should use using, however, me may consider thinner operator that handles all 3 cases at once.

[akarnokd]

I'm closing this issue due to inactivity. If you have further input on the issue, don't hesitate to reopen this issue or post a new one.

[BrianOn99]

@akarnokd I am using Observable.doOnUnsubscribe() heavily in RxJava1 in android, for resource clean-up such as hiding a "loading dialog". I saw that you suggest

you should use using, however, me may consider thinner operator that handles all 3 cases at once.

but I cannot figure out how to make such a thinner operator. Could you please kindly give me some suggestion or some code snippets?

[akarnokd]

See doFinally that has been added since the my original comment.

[BrianOn99]

Thanks! It seems to be a good replacement. I think it would be nice to include it in the last section "doOnCancel/doOnDispose/unsubscribeOn" of documentation https://github.com/ReactiveX/RxJava/wiki/What%27s-different-in-2.0

[akarnokd]

I've updated the wiki.