What causes "Missing gas limit" in nautechsystems/nautilus_trader?

Include gas_limit in the HyperSync block field selection

Missing gas limit

Error message

Missing gas limit

What it means

transform_hypersync_block reads the source block's gas_limit (a hex Quantity) and converts it to u64. The error fires when the gas_limit field is None, preventing construction of a complete domain Block.

Source

Thrown at crates/adapters/blockchain/src/hypersync/transform.rs:37

use nautilus_model::defi::{Block, Blockchain, hex::from_str_hex_to_u64};
use ustr::Ustr;

/// Converts a HyperSync block format to our internal [`Block`] type.
///
/// # Errors
///
/// Returns an error if required block fields are missing or if hex parsing fails.
pub fn transform_hypersync_block(
    chain: Blockchain,
    received_block: hypersync_client::simple_types::Block,
) -> Result<Block, anyhow::Error> {
    let number = received_block
        .number
        .ok_or_else(|| anyhow::anyhow!("Missing block number"))?;
    let gas_limit = from_str_hex_to_u64(
        received_block
            .gas_limit
            .ok_or_else(|| anyhow::anyhow!("Missing gas limit"))?
            .encode_hex()
            .as_str(),
    )?;
    let gas_used = from_str_hex_to_u64(
        received_block
            .gas_used
            .ok_or_else(|| anyhow::anyhow!("Missing gas used"))?
            .encode_hex()
            .as_str(),
    )?;
    let timestamp = from_str_hex_to_u64(
        received_block
            .timestamp
            .ok_or_else(|| anyhow::anyhow!("Missing timestamp"))?
            .encode_hex()
            .as_str(),
    )?;

View on GitHub (pinned to 18893faf8b)

Solutions

Include gas_limit in the HyperSync block field selection
Skip or re-fetch blocks missing gas_limit
Update/verify the hypersync-client version populates gas_limit
Inspect the raw response payload to confirm whether the upstream API omits the field

Example fix

// before
let gas_limit = from_str_hex_to_u64(received_block.gas_limit.ok_or_else(|| anyhow::anyhow!("Missing gas limit"))?.encode_hex().as_str())?;
// after
let Some(gas_limit_raw) = received_block.gas_limit else {
    tracing::warn!("hypersync block missing gas_limit; skipping block");
    return Ok(None);
};
let gas_limit = from_str_hex_to_u64(gas_limit_raw.encode_hex().as_str())?;

Defensive patterns

Strategy: validation

Validate before calling

if received_block.gas_limit.is_none() {
    tracing::warn!("skipping hypersync block without gas_limit");
    return Ok(None);
}

Type guard

fn block_has_gas_limit(b: &hypersync_client::simple_types::Block) -> bool {
    b.gas_limit.is_some()
}

Try / catch

match transform_hypersync_block(chain, block) {
    Ok(b) => /* use b */,
    Err(e) => { tracing::warn!("block transform failed: {e}"); continue; }
}

Prevention

Select gas_limit (and gas_used) fields in HyperSync block queries
Validate all required block fields before transformation
Handle partial blocks gracefully: skip, re-fetch, and alert on repeated gaps

When it happens

Trigger: transform_hypersync_block receives a hypersync_client::simple_types::Block whose gas_limit is None, called from pool_events_from_response while transforming a HyperSync response.

Common situations: HyperSync responses omitting gas_limit (partial blocks, API field selection gaps); upstream schema changes; blocks synthesized by tests or tooling without gas_limit set.

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

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/521c678d28e239dc. Report an issue: GitHub.