Exception in onCompleted() not propagate to onError()

[ronanM]

When an exception occurred in onCompleted() the exception is not propagate to onError().

Code of rx.operators.SafeObserver

    @Override
    public void onCompleted() {
        if (isFinished.compareAndSet(false, true)) {
            try {
                actual.onCompleted();
            } catch (Throwable e) {
                // handle errors if the onCompleted implementation fails, not just if the Observable fails
                onError(e);
            }
            // auto-unsubscribe
            subscription.unsubscribe();
        }
    }

In our case isFinished is already TRUE, so onError does nothing.

 @Override
    public void onError(Throwable e) {
        if (isFinished.compareAndSet(false, true)) {
           ...
        }
    }

[zsxwing]

That's intentional. According to Rx Contract, A observer should not receive both onCompleted and onError. You need to handle the exception in onCompleted by yourself.

[ronanM]

Ok the contract is clear.

So, I don't understand why in SafeObserver there is this code

catch (Throwable e) {
    // handle errors if the onCompleted implementation fails, not just if the Observable fails
    onError(e);
}

It's in contradiction with the grammar and because isFinished is set to true so this call is useless.

Why not call a global errorHandler or something like that in the catch ?

I don't understand.

Regards,
Ronan.

[benjchristensen]

Ha, yep that code is pretty useless. Kind of funny ... I'll submit a fix shortly.