Help: Subscribers behave differently depending on (...)

[Karam2B]

I have three examples of using the same subscriber here I have three examples of using the same subscriber, but for some reason the behaviour is completely different! let me know if you want me to repreduce this behavior in a repo

#[tokio::test]
async fn no_event_works_here() {
    let trace = tracing_subscriber::fmt()
        .with_max_level(tracing::Level::DEBUG)
        .finish();

    tracing::subscriber::with_default(trace, || async {
        // no_event_works_here
        tracing::debug!("only this but not");
    }).await
}

#[tokio::test]
async fn only_few_event_work_here() {
    let trace = tracing_subscriber::fmt()
        .with_max_level(tracing::Level::DEBUG)
        .finish()
        .set_default();

    // only this event work but not others
    tracing::debug!("only this but not");
    // this will not be displayed
    sqlx::query("...").fetch_one({}).await.unwrap()
    // some event that exist outside of the current crate
    // are not visible, let me know if you want a way to
    // repreduce the error
}

#[tokio::test]
async fn all_works() {
    let trace = tracing_subscriber::fmt()
        .with_max_level(tracing::Level::DEBUG)
        .finish()
        .set_global_default();

    // all event are tracked here
    // but I want to set up a subscriber for each test
    // similar to how "tracing::subscriber::with_default" looks like
    tracing::debug!("only this but not")
}

[mladedav]

In the first case, you're calling with_default but all you do in the closure that has the provided subscriber is create a future, which is returned from the function and you then await it outside, where you're back in a scope without an active subscriber.

The second example sets the subscriber for the current thread. Since tokio::test uses the current thread runtime by default, I would expect everything to be logged, but maybe sqlx is spawning a thread or something like that. So I'm not sure there.