`.buffered(0).next().await` hangs indefinitely

[nameexhaustion]

Reproducible example

#[test]
fn test() {
    use futures::StreamExt;
    tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .unwrap()
        .block_on(async {
            futures::stream::iter(0..10)
                .map(|x| std::future::ready(x))
                .buffered(0)
                .next()
                .await
                .unwrap();
        })
}

I don't think the current behavior (silently hanging) is ideal, but I'm also not sure of a better alternative - I can think of a few options -

• Take NonZeroUsize (or TryInto<NonZeroUsize> in the API
• Internally clamp n to be a minimum of 1
• Return None for next()
• Panic

[nakaryo716]

Hi! I was also confused by this behavior at first, so I understand the concern.

This issue is actually a duplicate of #2348.
It has already been fixed on the master branch, but the version published on crates.io is outdated, so we still encounter the problem there.

If you clone this repository and run it locally, you can confirm that the collect behavior works as expected.