nautechsystems/nautilus_trader · error

Failed to serialize the deployment manifest

Error message

Failed to serialize the deployment manifest

What it means

The validator serializes the deployment manifest to canonical JSON bytes with serde_json::to_vec in order to hash them with keccak256. If serialization fails (e.g. a map key type that cannot serialize, or a poisoned/invalid value), the library cannot form the canonical commitment and raises this error. In practice this indicates a corrupted or improperly typed manifest value rather than a network issue.

Source

Thrown at crates/adapters/blockchain/src/rpc/verification.rs:1251

    );
    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,
        "Deployment manifest digest must be nonzero"
    );
    let manifest = &config.deployment_manifest;
    anyhow::ensure!(
        manifest.version == config.manifest_version,
        "Deployment manifest version does not match its configured identity"
    );
    anyhow::ensure!(
        manifest.chain_id == anchor.chain_id && manifest.chain_name == anchor.chain_name,
        "Deployment manifest chain identity does not match the chain anchor"
    );
    let canonical_manifest = serde_json::to_vec(manifest)
        .map_err(|_| anyhow::anyhow!("Failed to serialize the deployment manifest"))?;
    anyhow::ensure!(
        keccak256(canonical_manifest) == manifest_digest,
        "Deployment manifest digest does not match its canonical content"
    );
    anyhow::ensure!(
        !manifest.contracts.is_empty() && !manifest.tokens.is_empty() && !manifest.pools.is_empty(),
        "Deployment manifest contracts, tokens, and pools are required"
    );
    let mut contract_addresses = HashSet::new();
    let mut roles = HashSet::new();

    for contract in &manifest.contracts {
        let address = Address::from_str(&contract.address)
            .map_err(|_| anyhow::anyhow!("Deployment manifest contains an invalid address"))?;
        anyhow::ensure!(
            contract_addresses.insert(address),
            "Deployment manifest contains a duplicate contract address"
        );

View on GitHub (pinned to 18893faf8b)

Solutions

1. Ensure all manifest fields use JSON-serializable types (string-keyed maps, Decimal/bytes represented as hex strings).
2. Round-trip the manifest through serde_json locally to reproduce and locate the failing field.
3. Pin the serde/serde_json versions used to build the manifest to those used by this crate.

Example fix

// before
contracts: HashMap<B256, ContractEntry>,   // non-string keys break serde_json
// after
contracts: BTreeMap<String, ContractEntry>, // hex-string keys, deterministic order

let bytes = serde_json::to_vec(&config.deployment_manifest)
    .expect("manifest must serialize canonically; check for non-string map keys or unsupported types");
let digest = keccak256(&bytes);
assert_eq!(digest.to_string(), config.manifest_digest);

match serde_json::to_vec(&config.deployment_manifest) {
    Ok(bytes) => { /* proceed with keccak256(&bytes) */ }
    Err(e) => eprintln!("manifest serialization failed: {e}; fix manifest field types"),
}

When it happens

Trigger: serde_json::to_vec(manifest) returning Err while validating `config.deployment_manifest` — typically a non-string map key (e.g. HashMap with B256/address keys) or a custom serializer failure.

Common situations: A manifest struct field changed to a type serde_json cannot serialize canonically; deserialized input carrying values that fail round-trip serialization; feature-flagged serde attributes altering serialization support.

Understand the failure class

Background: "JSON serialization failed", "not JSON serializable", "Failed to serialize": why JSON marshaling errors happen and how to fix them — this error's family across 46 libraries.

Related errors

• Python object has no to_json() method or __dict__ attribute
• Failed to parse hex quantity '{s}': {e}
• serialized position adjustment was not an object
• serialized enum variant was not an object
• Failed to serialize json `payload`: {e}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/43d2a1e7b5563459. Report an issue: GitHub.