defer / asynchronousFirstOrDefault in unit test seems to completely swallow exception output

[fatuhoku]

I've run up against some nasty behaviour. I've got an async operation here:

-(RACSignal *)foobar {
    return [RACSignal defer:^RACSignal * {
        RACSignal *resultSignal = [RACSignal empty];

        @try{

            @[][3];               // exceptions' log outputs are silenced if I don't use @try block

            resultSignal = [RACSignal createSignal:...];
        } @catch(NSException *exc) {
            NSLog(@"%@", exc);    // the exception can be caught here, though.
        } @finally {
            return resultSignal
        }
    }];
}

... which I test against in unit tests in the following way:

NSArray *values = [[[AsyncOperation foobar] collect] asynchronousFirstOrDefault:@[] success:nil error:&error];  // HANGS here

My tests hangs on that line and errors out, but nothing informative is printed. This is terrible for debugging.

The only way I can find out what happened is to catch the exception and PRINT the information from the exception manually using a @Try block. This shouldn't need to be the case.

Why is this happening?

[jlawton]

I get the exception in the console as normal when I run this on the main thread without the @try. The stack trace has 50-odd frames of RAC in it, but it seems fine.

[jspahrsummers]

Exceptions are not supposed to be recoverable in Objective-C, so we don't make any attempt to support it.

[fatuhoku]

Hmmm. It must be something else in my code. @jlawton you're right, the snippet I posted as it is works okay. But some almost identical code elsewhere in my codebase has its exceptions swallowed. Mysterious.

Thanks for now.