What causes "Chain checkpoint hash must be nonzero" in nautechsystems/nautilus_trader?

Set `anchor.checkpoint_hash` to the real 32-byte keccak digest of the checkpoint block or state root.

Chain checkpoint hash must be nonzero

Error message

Chain checkpoint hash must be nonzero

What it means

During chain anchor validation in the RPC verification layer, the anchor's checkpoint_hash is parsed into a 32-byte B256 and rejected if it equals B256::ZERO. A zero hash is never a valid checkpoint root, so the library treats it as a placeholder or uninitialized value. This guard prevents anchoring chain verification to a meaningless digest.

Source

Thrown at crates/adapters/blockchain/src/rpc/verification.rs:1220

        }
    }

    let endpoints = [
        normalize_endpoint(authoritative_url)?,
        normalize_endpoint(config.verifiers[0].http_rpc_url.expose_secret())?,
        normalize_endpoint(config.verifiers[1].http_rpc_url.expose_secret())?,
    ];
    ensure_distinct(endpoints.iter().map(String::as_str), "provider endpoints")?;

    let anchor = &config.chain_anchor;
    anyhow::ensure!(anchor.chain_id != 0, "Chain anchor ID must be nonzero");
    anyhow::ensure!(
        !anchor.chain_name.trim().is_empty(),
        "Chain anchor name is required"
    );
    let checkpoint_hash = B256::from_str(&anchor.checkpoint_hash)
        .map_err(|_| anyhow::anyhow!("Chain checkpoint hash must contain 32 hexadecimal bytes"))?;
    anyhow::ensure!(
        checkpoint_hash != B256::ZERO,
        "Chain checkpoint hash must be nonzero"
    );
    anyhow::ensure!(
        anchor.max_head_skew_blocks != 0
            && anchor.max_head_age_secs != 0
            && anchor.max_future_drift_secs != 0,
        "Chain head skew, age, and future-drift limits must be nonzero"
    );
    anyhow::ensure!(
        !config.manifest_version.trim().is_empty(),
        "Deployment manifest version is required"
    );
    let manifest_digest = B256::from_str(&config.manifest_digest).map_err(|_| {
        anyhow::anyhow!("Deployment manifest digest must contain 32 hexadecimal bytes")
    })?;
    anyhow::ensure!(
        manifest_digest != B256::ZERO,

View on GitHub (pinned to 18893faf8b)

Solutions

Set `anchor.checkpoint_hash` to the real 32-byte keccak digest of the checkpoint block or state root.
Copy the checkpoint hash exactly as published by the chain operator (0x-prefixed 64 hex chars).
If the hash is unknown, fetch it from the deployment's canonical manifest or the chain's finalized checkpoint rather than guessing.

Example fix

// before
let anchor = ChainAnchor { chain_name: "base".into(), checkpoint_hash: "0x0000000000000000000000000000000000000000000000000000000000000000".into(), ..Default::default() };
// after
let anchor = ChainAnchor { chain_name: "base".into(), checkpoint_hash: "0x9f2c...ab01".into(), ..Default::default() }; // real 32-byte hash

Defensive patterns

Strategy: validation

Validate before calling

fn checkpoint_hash_ok(anchor: &ChainAnchor) -> bool {
    B256::from_str(&anchor.checkpoint_hash)
        .map(|h| h != B256::ZERO)
        .unwrap_or(false)
}
assert!(checkpoint_hash_ok(&anchor), "checkpoint_hash must be a nonzero 32-byte hex value");

Type guard

fn is_nonzero_b256(s: &str) -> Option<B256> {
    B256::from_str(s).ok().filter(|h| *h != B256::ZERO)
}

Prevention

Load checkpoint hashes from the chain operator's published deployment file, never hand-typed.
Add a unit test asserting every bundled anchor has a nonzero checkpoint hash.
Reject all-zero hex literals in config linting before deployment.

When it happens

Trigger: Calling the verification setup that validates a ChainAnchor whose `checkpoint_hash` field parses to valid hex but is exactly 32 zero bytes (0x0000...0000).

Common situations: A stub or template config where the hash was never filled in; an operator zeroing the field to 'disable' checkpoint checks; generated configs defaulting the hash to all zeros.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/29b004bb94dd11f4. Report an issue: GitHub.