Panic after calling take.

[kriomant]

While trying to implement cell with expiration, I found that following code

/*
[dependencies]
async-once-cell = "*"
tokio = { version = "*", features = ["macros", "rt-multi-thread"] }
*/

#[tokio::main]
async fn main() {
    let mut cell = async_once_cell::OnceCell::new_with(Some(0u64));
    let value = cell.get();
    let _ = cell.take();
    let _ = cell.get_or_init(async { 1 }).await;
    println!("done");
}

playground

causes

thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /home/explorer/.cargo/registry/src/github.com-1ecc6299db9ec823/async-once-cell-0.4.2/src/lib.rs:455:51
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

here:

        // Safety: initialized on all paths
        Ok(unsafe { (&*self.value.get()).as_ref().unwrap() })

It seems not all paths ensures value is initialised.

[danieldg]

Please check if master fixes this; I just noticed that there's a commit to fix this issue but it wasn't included in 0.4.2. I'll release 0.4.3 with that later today.