nautechsystems/nautilus_trader · error

Cannot process partial quote for {instrument_id}: missing bi

Error message

Cannot process partial quote for {instrument_id}: missing bid_price and no cached value

What it means

QuoteCache::process merges partial quote updates with the previously cached quote for the instrument. This error means bid_price was None and there is no cached quote for the instrument, so bid_price cannot be resolved and no complete QuoteTick can be built.

Source

Thrown at crates/common/src/cache/quote.rs:128

    /// Returns an error if:
    /// - Any required field is `None` and there is no cached quote.
    /// - The first quote received is incomplete (no cached values to merge with).
    #[expect(clippy::too_many_arguments)]
    pub fn process(
        &mut self,
        instrument_id: InstrumentId,
        bid_price: Option<Price>,
        ask_price: Option<Price>,
        bid_size: Option<Quantity>,
        ask_size: Option<Quantity>,
        ts_event: UnixNanos,
        ts_init: UnixNanos,
    ) -> anyhow::Result<QuoteTick> {
        let cached = self.quotes.get(&instrument_id);

        // Resolve each field: use provided value or fall back to cache
        let Some(bid_price) = bid_price.or_else(|| cached.map(|quote| quote.bid_price)) else {
            anyhow::bail!(
                "Cannot process partial quote for {instrument_id}: missing bid_price and no cached value"
            );
        };

        let Some(ask_price) = ask_price.or_else(|| cached.map(|quote| quote.ask_price)) else {
            anyhow::bail!(
                "Cannot process partial quote for {instrument_id}: missing ask_price and no cached value"
            );
        };

        let Some(bid_size) = bid_size.or_else(|| cached.map(|quote| quote.bid_size)) else {
            anyhow::bail!(
                "Cannot process partial quote for {instrument_id}: missing bid_size and no cached value"
            );
        };

        let Some(ask_size) = ask_size.or_else(|| cached.map(|quote| quote.ask_size)) else {
            anyhow::bail!(

View on GitHub (pinned to 18893faf8b)

Solutions

1. Wait for (or request) a full quote snapshot before forwarding partial updates to process
2. Skip partial updates until the first complete quote for that instrument has been cached
3. Provide an explicit bid_price instead of None when no cache entry exists
4. Seed the cache with a full quote before applying deltas

Example fix

// before
quote_cache.process(instrument_id, None, ask, bid_size, ask_size, ts_event, ts_init)?;
// after
if quote_cache.contains(&instrument_id) {
    quote_cache.process(instrument_id, None, ask, bid_size, ask_size, ts_event, ts_init)?;
} // else wait for a complete quote

fn can_process(cache: &QuoteCache, id: &InstrumentId, bid_price: Option<Price>) -> bool {
    bid_price.is_some() || cache.contains(id)
}

match quote_cache.process(instrument_id, bid_price, ask_price, bid_size, ask_size, ts_event, ts_init) {
    Ok(quote) => /* forward quote */,
    Err(e) if e.to_string().contains("missing bid_price") => {
        // no cached quote yet: skip this partial update until a full quote arrives
    }
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Calling process(instrument_id, None, ask_price, bid_size, ask_size, ...) as the first update for an instrument (nothing cached yet), or after cache.clear() (e.g. post-reconnect) when the next update is still partial.

Common situations: Feeding top-of-book delta-style feeds into a freshly started/restarted process; a reconnect that cleared the cache followed by partial updates; subscribing mid-session where the first tick omits the bid side.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Cannot process partial quote for {instrument_id}: missing as
• Cannot process partial quote for {instrument_id}: missing bi
• Cannot process partial quote for {instrument_id}: missing as
• Missing ask quote for pair {pair}
• DataActor {} must be registered before calling `cache()` - t

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/be1ab0c8604f0a15. Report an issue: GitHub.