NPE in OnSubscribeFromIterable

[benjchristensen]

A report from RxJava 0.19.x:

Caused by: java.lang.NullPointerException
        at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:39)
        at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:29)
        at rx.Observable$2.call(Observable.java:159)

[benjchristensen]

In 0.19 an NPE could happen if the Iterable was null: https://github.com/ReactiveX/RxJava/blob/0.19.x/rxjava-core/src/main/java/rx/internal/operators/OnSubscribeFromIterable.java#L39

This is fixed in 1.0: https://github.com/ReactiveX/RxJava/blob/v1.0.0-rc.5/src/main/java/rx/internal/operators/OnSubscribeFromIterable.java#L43

[zsxwing]

I feel a null Iterable is usually a programming error.I think throwing an NullPointerException in the constructor of OnSubscribeFromIterable is better. RxJava should not hide such error, so that people can find their mistake quickly.