nautechsystems/nautilus_trader · error · anyhow::Error

OrderList denied: duplicate {order_list.id}

Error message

OrderList denied: duplicate {order_list.id}

What it means

When submitting an order list, the strategy checks `cache.order_list_exists(&order_list.id)`; if a list with the same ID is already in the cache the submission is rejected with `OrderList denied: duplicate {order_list.id}`. This guards against submitting the same logical order list twice (double-fire of the same request).

Source

Thrown at crates/trading/src/strategy/mod.rs:272

            core.order_factory().create_list(&mut orders, ts_init)
        };

        if let Err(e) = order_list.validate() {
            log::error!("OrderList denied: {e}");
            anyhow::bail!("OrderList denied: {e}");
        }

        {
            let cache_rc = core.cache_rc();
            let mut cache = cache_rc.try_borrow_mut().map_err(|_| {
                anyhow::anyhow!(
                    "Cannot submit order list {}: cache is currently borrowed",
                    order_list.id
                )
            })?;

            if cache.order_list_exists(&order_list.id) {
                anyhow::bail!("OrderList denied: duplicate {}", order_list.id);
            }

            for order in &orders {
                if cache.order_exists(&order.client_order_id()) {
                    anyhow::bail!(
                        "Order in list denied: duplicate {}",
                        order.client_order_id()
                    );
                }
            }

            cache.add_order_list(order_list.clone())?;
            for order in &orders {
                cache.add_order(order.clone(), position_id, client_id, true)?;
            }
        }

        for order in &orders {

View on GitHub (pinned to 18893faf8b)

Solutions

1. Check `self.cache.order_list_exists(order_list.id)` before submitting, or make the call idempotent.
2. On retry, create a fresh order list via the OrderFactory so new client_order_ids are generated.
3. Deduplicate your signal/event source so the same condition does not trigger submission twice.
4. Log the order_list.id on submission and skip if it matches the last submitted list.

Example fix

// before
self.submit_order_list(order_list)  # called again on retry -> duplicate
// after
if not self.cache.order_list_exists(order_list.id):
    self.submit_order_list(order_list)
else:
    self.log.warning(f'Order list {order_list.id} already submitted')

if self.cache.order_list_exists(order_list.id):
    self.log.warning(f'{order_list.id} already submitted — skipping')
else:
    self.submit_order_list(order_list)

def can_submit_order_list(strategy, order_list):
    return not strategy.cache.order_list_exists(order_list.id)

try:
    if not self.cache.order_list_exists(order_list.id):
        self.submit_order_list(order_list)
except Exception as e:
    self.log.error(f'Order list submission failed: {e}')

When it happens

Trigger: Calling `submit_order_list` twice with the same OrderList / same client_order_id set — e.g. retrying a submission after an error, or calling submit from both a handler and a timer for the same list object.

Common situations: Retry logic that re-submits the original list after a transient failure without creating a new one; duplicate signal processing creating identical lists; replayed events in backtests resubmitting historical orders; code path that submits on both on_data and on_bar for the same condition.

Related errors

• IDEMPOTENT_DUPLICATE
• External order claim for {instrument_id} appears more than o
• OrderList denied: duplicate {}
• Failed to reserve execution intent for signer {} on chain {}
• Failed to commit replacement transaction: {e}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/140a53447d25ea6c. Report an issue: GitHub.