nautechsystems/nautilus_trader · error

Missing parent hash

Error message

Missing parent hash

What it means

transform_hypersync_block requires parent_hash to link the new Block into the chain. The HyperSync block type carries parent_hash as optional; when absent the transform fails with this error instead of producing an orphaned Block with an empty parent reference.

Source

Thrown at crates/adapters/blockchain/src/hypersync/transform.rs:63

            .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(),
    )?;

    let mut block = Block::new(
        received_block
            .hash
            .ok_or_else(|| anyhow::anyhow!("Missing hash"))?
            .to_string(),
        received_block
            .parent_hash
            .ok_or_else(|| anyhow::anyhow!("Missing parent hash"))?
            .to_string(),
        number,
        Ustr::from(
            received_block
                .miner
                .ok_or_else(|| anyhow::anyhow!("Missing miner"))?
                .to_string()
                .as_str(),
        ),
        gas_limit,
        gas_used,
        UnixNanos::new(timestamp * NANOSECONDS_IN_SECOND),
        Some(chain),
    );

    if let Some(base_fee_hex) = received_block.base_fee_per_gas {
        let s = base_fee_hex.encode_hex();
        let val = U256::from_str_radix(s.trim_start_matches("0x"), 16)?;

View on GitHub (pinned to 18893faf8b)

Solutions

1. Include parent_hash in the HyperSync query field selection.
2. Skip or special-case the genesis block (hash of all zeros) before calling transform_hypersync_block.
3. If chain linkage is not needed, pass a zeroed parent hash (0x000...0) as a default.
4. Verify the block range is finalized so HyperSync returns complete parent references.

Example fix

// before
let parent_hash = received_block.parent_hash.ok_or_else(|| anyhow::anyhow!("Missing parent hash"))?.to_string();
// after (genesis-safe default)
let parent_hash = received_block
    .parent_hash
    .map(|h| h.to_string())
    .unwrap_or_else(|| "0x0000000000000000000000000000000000000000000000000000000000000000".to_string());

const ZERO_HASH: &str = "0x0000000000000000000000000000000000000000000000000000000000000000";
fn is_genesis(b: &hypersync_client::simple_types::Block) -> bool {
    b.parent_hash.is_none()
        || b.parent_hash.as_ref().map(|h| h.to_string()).as_deref() == Some(ZERO_HASH)
}
// special-case genesis before transforming

fn has_parent_hash(b: &hypersync_client::simple_types::Block) -> bool {
    matches!(b.parent_hash, Some(_))
}

match transform_hypersync_block(chain, block) {
    Ok(b) => process(b),
    Err(e) if e.to_string().contains("Missing parent hash") => {
        tracing::warn!(block = ?block.number, "genesis or incomplete block; skipping");
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: pool_events_from_response encountering a HyperSync block whose parent_hash is None — e.g. the query projection omitted parent_hash, or the genesis/pending block record lacks a parent reference.

Common situations: Processing the genesis block (which has no parent) through this transform; selective HyperSync queries excluding parent_hash; fixtures or cached responses missing the field.

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

• Missing hash
• Missing transaction hash in log
• Missing transaction index in the log
• Missing log index in the log
• Missing block number in the log

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/2335787fccd7cdc4. Report an issue: GitHub.