nautechsystems/nautilus_trader · error · anyhow::Error

Failed to apply IBOrderTags because IB order JSON is not an

Error message

Failed to apply IBOrderTags because IB order JSON is not an object

What it means

apply_order_field_update maintains a parallel serde_json::Value view of the IBOrder so it can insert-then-restore on failure. If that Value is not a JSON object (an internal invariant — it is initialized from the serialized IBOrder), the update cannot proceed and the function bails.

Source

Thrown at crates/adapters/interactive_brokers/src/execution/transform/tags.rs:102

            anyhow::bail!("Invalid IBOrderTags field {field}: {value}");
        };

        for (field, value) in updates.drain(..) {
            apply_order_field_update(ib_order, &mut order_value, &field, value)?;
        }
    }

    Ok(())
}

fn apply_order_field_update(
    ib_order: &mut IBOrder,
    order_value: &mut Value,
    field: &str,
    value: Value,
) -> anyhow::Result<()> {
    let Some(order_obj) = order_value.as_object_mut() else {
        anyhow::bail!("Failed to apply IBOrderTags because IB order JSON is not an object");
    };

    if !order_obj.contains_key(field) {
        anyhow::bail!("Unsupported IBOrderTags field: {field}");
    }

    let previous = order_obj.insert(field.to_string(), value);

    match serde_json::from_value::<IBOrder>(order_value.clone()) {
        Ok(updated_order) => {
            *ib_order = updated_order;
            Ok(())
        }
        Err(e) => {
            let Some(order_obj) = order_value.as_object_mut() else {
                anyhow::bail!(
                    "Failed to restore IB order JSON after invalid IBOrderTags field: {field}"
                );

View on GitHub (pinned to 18893faf8b)

Solutions

  1. Verify the IBOrder serializes to a JSON object (custom Serialize impls or newtype wrappers break this) Update the adapter: if IBOrder's serialization changed, the tag-applier's assumption must be fixed in the crate Report as a bug if stock IBOrder triggers it — this is an internal invariant violation
Defensive patterns

Strategy: try-catch

Try / catch

match nautilus_order_to_ib_order(...) {
    Err(e) if e.to_string().contains("IB order JSON is not an object") => {
        // internal invariant broken; log full order context and report a bug
        tracing::error!("adapter invariant violated: {e:#}");
    }
    r => r?,
}

Prevention

When it happens

Trigger: apply_ib_order_tag_overlay -> apply_order_field_update when order_value.as_object_mut() returns None. Should only occur if the serialized IBOrder is not an object, e.g. a corrupted or non-struct serialization of IBOrder.

Common situations: Rare; points to an internal inconsistency such as IBOrder serializing to a non-object (custom Serialize impl, version drift between serializer and tag-applier).

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/d6dacae266680e7d. Report an issue: GitHub.