Replay subject with asMaybes and take

[thenikso]

I'm having trouble with a scenario like this:

RACReplaySubject *subject = [RACReplaySubject subject];
[subject sendError:[[NSError alloc] init]];

[[[subject asMaybes] take:1] subscribeNext:^(id x) {
  // I loop 4evar
} completed:^{
  // I never complete
}];

And this is because asMaybes actually is "asMaybesAndRepeatOnError" and take:1 valuesTaken goes past count.
This makes me think to the Materialize as discussed in #90

To be more specific, I'm trying to make something like this (pseudocode):

RACAble(property) 
select:^id(id x) {
    return [[<a replay subject> asMaybe] take:1]; }
switch
subscribeNext:...

The goal is to keep the outer rac alive even if the inner one fails.
If I move asMaybe after switch the replay subject builded by the RACAble macro, immediately fires the subscribable again, which is not desired.

Wouldn't be this a use case for a subscribable that convert to maybes but completes upon error?

[joshaber]

-asMaybes is poorly defined. We should probably just get rid of it.

The better approach depends on what you want to do when that inner replay subject errors. You probably want to use -catch: or -catchTo: instead of -asMaybes.

For example, if you just want it to complete instead of erroring:

RACAble(property) 
select:^id(id x) {
    return [[<a replay subject> catchTo:[RACSubscribable empty]] take:1]; }
switch
subscribeNext:...

Or just yield nil:

RACAble(property) 
select:^id(id x) {
    return [[<a replay subject> catchTo:[RACSubscribable return:nil]] take:1]; }
switch
subscribeNext:...

[thenikso]

Using catch solves my issue, thanks.

As a side note, this also loops indefinitely:

RACReplaySubject *subject = [RACReplaySubject subject];
[subject sendNext:@(1)];
[subject sendCompleted];
[[[subject repeat] take:1] subscribeNext:^(id x) { ... }];

[joshaber]

Nice catch. I created #94 for that issue.