{"record":{"id":"8e4a8e983c5c1249","repo":"nautechsystems/nautilus_trader","slug":"failed-converting-gas-cost-to-u128","errorCode":null,"errorMessage":"Failed converting gas cost to u128","messagePattern":"Failed converting gas cost to u128","errorType":"exception","errorClass":"anyhow::Error","httpStatus":null,"severity":"error","filePath":"crates/adapters/dydx/src/grpc/builder.rs","lineNumber":100,"sourceCode":"        }\n    }\n\n    /// Calculate fee from gas usage.\n    fn calculate_fee_from_gas(&self, gas_used: u64) -> Result<Fee, anyhow::Error> {\n        let gas_multiplier = Decimal::try_from(GAS_MULTIPLIER)?;\n        let gas_limit = Decimal::from(gas_used) * gas_multiplier;\n\n        // Gas price for dYdX (typically 0.025 adydx per gas)\n        let gas_price = Decimal::new(25, 3); // 0.025\n        let amount = (gas_price * gas_limit).ceil();\n\n        let gas_limit_u64 = gas_limit\n            .to_u64()\n            .ok_or_else(|| anyhow::anyhow!(\"Failed converting gas limit to u64\"))?;\n\n        let amount_u128 = amount\n            .to_u128()\n            .ok_or_else(|| anyhow::anyhow!(\"Failed converting gas cost to u128\"))?;\n\n        Ok(Fee::from_amount_and_gas(\n            Coin {\n                amount: amount_u128,\n                denom: self\n                    .fee_denom\n                    .parse()\n                    .map_err(|e| anyhow::anyhow!(\"Invalid fee denom: {e}\"))?,\n            },\n            gas_limit_u64,\n        ))\n    }\n\n    /// Get default fee (zero fee).\n    fn default_fee() -> Fee {\n        Fee {\n            amount: vec![],\n            gas_limit: 0,","sourceCodeStart":82,"sourceCodeEnd":118,"githubUrl":"https://github.com/nautechsystems/nautilus_trader/blob/18893faf8b356be3320add8de2f861b0b647cf06/crates/adapters/dydx/src/grpc/builder.rs#L82-L118","documentation":"After computing amount = ceil(gas_price * gas_limit) as a Decimal, calculate_fee_from_gas converts it to u128 for the cosmrs Coin amount. If the computed fee amount exceeds u128::MAX (or is otherwise non-convertible), this error is returned.","triggerScenarios":"Calling calculate_fee with a gas_limit so large that 0.025 * gas_limit, ceiled, overflows u128 (~3.4e38) — i.e. gas_limit above roughly 1.36e40; or a negative/NaN-like Decimal result that cannot convert.","commonSituations":"Passing an unvalidated gas limit taken from a malformed upstream response; a bug in gas estimation producing enormous values; unit confusion (e.g. passing wei-scaled values where raw gas was expected).","solutions":["Validate/clamp the gas limit before calling calculate_fee so gas_price * gas_limit stays far below u128::MAX.","Trace the gas value's source and fix any unit scaling that inflated it.","Use a realistic gas ceiling (dYdX block gas limits are millions of gas) and reject estimates above it upstream.","Log the offending gas_limit and amount when the error occurs to identify the estimation bug."],"exampleFix":"// before\nlet gas_limit = Decimal::from_i128_with_scale(2, 40); // absurd -> amount overflows u128\n// after\nlet gas_limit = Decimal::from(2_500_000u64); // typical tx gas","handlingStrategy":"validation","validationCode":"fn fee_fits_u128(gas_limit: Decimal) -> bool {\n    let amount = Decimal::new(25, 3) * gas_limit;\n    amount.is_sign_positive() && amount <= Decimal::from(u128::MAX)\n}","typeGuard":null,"tryCatchPattern":"let fee = client.calculate_fee(instrument_id, gas_limit)\n    .map_err(|e| {\n        if e.to_string().contains(\"gas cost to u128\") {\n            // reject/repair the oversized gas estimate upstream\n        }\n        e\n    })?;","preventionTips":["Reject gas estimates above realistic block gas limits before fee computation","Check unit scaling of values taken from upstream APIs","Log gas_limit when fee conversion fails to find the estimation bug"],"tags":["dydx","fee","decimal-conversion","overflow","gas"],"backgroundTag":"value-out-of-range","analyzedSha":"18893faf8b356be3320add8de2f861b0b647cf06","analyzedAt":"2026-09-08T20:49:34.690Z","contentChangedAt":"2026-09-08T20:49:34.690Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}