[brandur]

It was called to my attention last week that it turns out that what's
been traditionally the main date/time library in Rust, chrono, is
actually soft deprecated [1]. The chrono maintainer recommends jiff [2]
as a replacement.

I figure that since River Rust is still quite new and River Pro for Rust
is still unreleased, it's the best time ever to make this jump. Although
annoying, jiff does seem to be very thoughtfully designed, with heavy
inspiration from Temporal in JavaScript.

[1] chronotope/chrono#1768
[2] https://crates.io/crates/jiff

[brandur]

@bgentry This really sucks, but chrono's never going to get less deprecated, so the best time to switch is still probably now.

Jiff does seem a little better designed, and there was some nice simplification opportunities. For example, previously River had to do some pretty gnarly stuff to get specific RFC3339 formatting:

pub(crate) fn format_rfc3339_nano(timestamp: DateTime<Utc>) -> String {
    let mut formatted = timestamp.to_rfc3339_opts(SecondsFormat::Secs, true);
    let nanos = timestamp.nanosecond() % 1_000_000_000;
    if nanos > 0 {
        let fraction = format!("{nanos:09}");
        formatted.insert(formatted.len() - 1, '.');
        formatted.insert_str(formatted.len() - 1, fraction.trim_end_matches('0'));
    }
    formatted
}

Now it's just timestamp.to_string() because jiff's accepted that RFC3339 is the canonical format for timestamp strings.

Codex had some ideas about potentially putting in a date/time indirection layer to River, but that's definitely got some tradeoffs. I think the BurntSushi crates (which jiff is) have a pretty good maintenance track record, so it might be worth being a bit more optimistic about this one.