nautechsystems/nautilus_trader · error · anyhow::Error

Failed to calculate price impact: {e}

Error message

Failed to calculate price impact: {e}

What it means

This public `get_price_impact_bps` wraps the inner `SwapTradeInfo::get_price_impact_bps` call and, when trade-info initialization fails (i.e. `trade_info` is None), re-raises the underlying error with the message `Failed to calculate price impact: {e}`. It is an error-context wrapper: the root cause is the uninitialized trade info reported by `check_if_trade_info_initialized`.

Source

Thrown at crates/model/src/defi/pool_analysis/quote.rs:219

            self.amount1.unsigned_abs()
        }
    }

    /// Calculates price impact in basis points (requires token references for decimal adjustment).
    ///
    /// Price impact measures the market movement caused by the swap size,
    /// excluding fees. This is the percentage change in spot price from
    /// before to after the swap.
    ///
    /// # Returns
    /// Price impact in basis points (10000 = 100%)
    ///
    /// # Errors
    /// Returns error if price calculations fail
    pub fn get_price_impact_bps(&mut self) -> anyhow::Result<u32> {
        match self.check_if_trade_info_initialized() {
            Ok(trade_info) => trade_info.get_price_impact_bps(),
            Err(e) => anyhow::bail!("Failed to calculate price impact: {e}"),
        }
    }

    /// Calculates slippage in basis points (requires token references for decimal adjustment).
    ///
    /// Slippage includes both price impact and fees, representing the total
    /// deviation from the spot price before the swap. This measures the total
    /// cost to the trader.
    ///
    /// # Returns
    /// Total slippage in basis points (10000 = 100%)
    ///
    /// # Errors
    /// Returns error if price calculations fail
    pub fn get_slippage_bps(&mut self) -> anyhow::Result<u32> {
        match self.check_if_trade_info_initialized() {
            Ok(trade_info) => trade_info.get_slippage_bps(),
            Err(e) => anyhow::bail!("Failed to calculate slippage: {e}"),

View on GitHub (pinned to 18893faf8b)

Solutions

1. Call `calculate_trade_info()` on the quote before requesting price impact.
2. Read the wrapped inner message to confirm the root cause is uninitialized trade info, not a math failure.
3. Guard with a helper that checks/initializes trade info once per quote.
4. If trade info can legitimately be absent, handle the Result instead of `?`-propagating into caller code.

Example fix

// before
let mut quote = Quote::new(pool, amount_in);
let impact_bps = quote.get_price_impact_bps()?;
// after
let mut quote = Quote::new(pool, amount_in);
quote.calculate_trade_info()?;
let impact_bps = quote.get_price_impact_bps()?;

quote.calculate_trade_info()?; // avoids the wrapper error entirely

let impact_bps = match quote.get_price_impact_bps() {
    Ok(v) => v,
    Err(e) if e.to_string().contains("Failed to calculate price impact") => {
        quote.calculate_trade_info()?;
        quote.get_price_impact_bps()?
    },
    Err(e) => return Err(e),
};

When it happens

Trigger: Calling `get_price_impact_bps()` on a quote whose `trade_info` was never initialized via `calculate_trade_info()`. Observed in tests as `test_metric_errors_propagate_from_trade_info`.

Common situations: Forgetting the `calculate_trade_info()` step before reading price impact; early-return paths that skip initialization; copying example code that initialized slippage but not price impact (shared init means either order fails identically).

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• Trade info is not initialized. Please call calculate_trade_i
• Failed to calculate slippage: {e}
• Cannot quote swap with zero amount
• Slippage {actual_slippage} bps exceeds tolerance {max_slippa
• Insufficient liquidity: requested {amount_out_requested}, av

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/a85ace93f8169ef3. Report an issue: GitHub.