GasFees.mul() throws BigInt error when scalar is a float

[awprojs]

Description

GasFees.mul(scalar) throws a TypeError when scalar is a non-integer (e.g. 1.5), because the result of Number(this.feePerDaGas) * scalar produces a float that cannot be converted to BigInt.

Reproduction

This is hit in normal CLI usage. Both cli-wallet/utils/options/fees.js and wallet-sdk/base-wallet/base_wallet.js call:

const maxFeesPerGas = (await node.getCurrentMinFees()).mul(1 + MIN_FEE_PADDING);

Where MIN_FEE_PADDING is 0.5, so scalar = 1.5. When the node returns fees like feePerL2Gas = 2910685593001n, the multiplication produces:

Number(2910685593001n) * 1.5 = 4366028389501.5

Which then fails:

TypeError: The number 4366028389501.5 cannot be converted to a BigInt because it is not an integer

Location

@aztec/stdlib/dest/gas/gas_fees.js, line 40:

mul(scalar) {
    if (scalar === 1 || scalar === 1n) {
        return this.clone();
    } else if (typeof scalar === 'bigint') {
        return new GasFees(this.feePerDaGas * scalar, this.feePerL2Gas * scalar);
    } else {
        // BUG: this can produce non-integer results
        return new GasFees(Number(this.feePerDaGas) * scalar, Number(this.feePerL2Gas) * scalar);
    }
}

Suggested Fix

Wrap in Math.ceil() (or Math.round()):

return new GasFees(
    Math.ceil(Number(this.feePerDaGas) * scalar),
    Math.ceil(Number(this.feePerL2Gas) * scalar)
);

Math.ceil makes sense here since this is used for fee estimation — rounding up is safer than rounding down.

Environment

• @aztec/stdlib versions: 4.1.2, 4.1.3 (both affected)
• Hit on Aztec Alpha mainnet where real gas prices produce large values