nautechsystems/nautilus_trader · error · anyhow::Error

Invalid value for `update_action`: {update_action}

Error message

Invalid value for `update_action`: {update_action}

What it means

decode_statistics_msg converts a Databento statistics record into a DatabentoStatistics event. The record's update_action byte must map to a known DatabentoStatisticUpdateAction; any unmapped value aborts the decode with this anyhow error instead of producing an event.

Source

Thrown at crates/adapters/databento/src/decode/custom.rs:87

pub fn decode_statistics_msg(
    msg: &dbn::StatMsg,
    instrument_id: InstrumentId,
    price_precision: u8,
    ts_init: Option<UnixNanos>,
) -> anyhow::Result<Option<DatabentoStatistics>> {
    let Some(stat_type) = u8::try_from(msg.stat_type)
        .ok()
        .and_then(DatabentoStatisticType::from_u8)
    else {
        log::warn!(
            "Skipping unsupported `stat_type` {} for {instrument_id}",
            msg.stat_type,
        );
        return Ok(None);
    };
    let update_action =
        DatabentoStatisticUpdateAction::from_u8(msg.update_action).ok_or_else(|| {
            anyhow::anyhow!("Invalid value for `update_action`: {}", msg.update_action)
        })?;
    let ts_event = msg.ts_recv.into();
    let ts_init = ts_init.unwrap_or(ts_event);

    Ok(Some(DatabentoStatistics::new(
        instrument_id,
        stat_type,
        update_action,
        decode_optional_price(msg.price, price_precision),
        decode_optional_quantity(msg.quantity)?,
        msg.channel_id,
        msg.stat_flags,
        msg.sequence,
        msg.ts_ref.into(),
        msg.ts_in_delta,
        msg.hd.ts_event.into(),
        ts_event,
        ts_init,

View on GitHub (pinned to 18893faf8b)

Solutions

  1. Upgrade nautilus-trader / the databento adapter to a version supporting the newer DBN schema
  2. Log and skip unknown update_action values instead of hard-failing (mirroring the unknown stat_type handling)
  3. Check the record's DBN version and the update_action value to confirm whether the schema is newer
  4. Report/patch DatabentoStatisticUpdateAction::from_u8 to map the new value

Example fix

// before
let update_action = DatabentoStatisticUpdateAction::from_u8(msg.update_action)
    .ok_or_else(|| anyhow!("Invalid value for `update_action`: {}", msg.update_action))?;
// after
let Some(update_action) = DatabentoStatisticUpdateAction::from_u8(msg.update_action) else {
    log::warn("Skipping statistics with unknown update_action {}", msg.update_action);
    return Ok(None);
};
Defensive patterns

Strategy: validation

Validate before calling

// Rust
let ok = DatabentoStatisticUpdateAction::from_u8(msg.update_action).is_some();

Try / catch

// Rust
Err(e) => log::warn("skip: {e:#}"),

Prevention

When it happens

Trigger: Feeding a Statistics record whose msg.update_action raw u8 is not recognized by DatabentoStatisticUpdateAction::from_u8 — typically a DBN schema revision introducing a new update action the decoder does not know.

Common situations: Replaying historical data recorded with a newer databento DBN version than the adapter supports; unexpected exchange-side statistics update actions in live streams; corrupted records.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/ae84822ef635584a. Report an issue: GitHub.