Function warn_on_singleton_overwrite

crates/openshell-driver-vm/src/lifecycle.rs:689–710

(
    extension_name: &str,
    field: &str,
    prev: Option<T>,
    next: Option<T>,
)

}

fn warn_on_singleton_overwrite<T>(
    extension_name: &str,
    field: &str,
    prev: Option<T>,
    next: Option<T>,
) where
    T: AsRef<str> + std::fmt::Display + PartialEq,
{
    let (Some(prev), Some(next)) = (prev, next) else {
        return;
    };
    if prev == next {
        return;
    }
    tracing::warn!(
        extension = extension_name,
        field,
        previous = %prev,
        next = %next,
        "vm driver: lifecycle extension overwrote a singleton launch-plan field set by an earlier extension"
    );
}

pub fn extension_state_dir(
    sandbox_state_dir: &Path,