fix: loading salt into buffer in cli

yarn-project/cli/src/index.ts

@@ -30,19 +30,14 @@ import {
   getAbiFunction,
   getContractAbi,
   getExampleContractArtifacts,
+  getSaltFromHexString,
   getTxSender,
   prepTx,
+  stripLeadingHex,
 } from './utils.js';
 
 const accountCreationSalt = Fr.ZERO;
 
-const stripLeadingHex = (hex: string) => {
-  if (hex.length > 2 && hex.startsWith('0x')) {
-    return hex.substring(2);
-  }
-  return hex;
-};
-
 const { ETHEREUM_HOST, AZTEC_RPC_HOST, PRIVATE_KEY, API_KEY } = process.env;
 
 /**
@@ -160,14 +155,18 @@ export function getProgram(log: LogFn, debugLogger: DebugLogger): Command {
       '-k, --public-key <string>',
       'Optional encryption public key for this address. Set this value only if this contract is expected to receive private notes, which will be encrypted using this public key.',
     )
-    .option('-s, --salt <string>', 'Optional deployment salt as a hex string for generating the deployment address.')
+    .option(
+      '-s, --salt <hex string>',
+      'Optional deployment salt as a hex string for generating the deployment address.',
+      getSaltFromHexString,
+    )
     .action(async (abiPath, options: any) => {
       const contractAbi = await getContractAbi(abiPath, log);
       const constructorAbi = contractAbi.functions.find(({ name }) => name === 'constructor');
 
       const client = await createCompatibleClient(options.rpcUrl, debugLogger);
       const publicKey = options.publicKey ? Point.fromString(options.publicKey) : undefined;
-      const salt = options.salt ? Fr.fromBuffer(Buffer.from(stripLeadingHex(options.salt), 'hex')) : undefined;
+
       const deployer = new ContractDeployer(contractAbi, client, publicKey);
 
       const constructor = getAbiFunction(contractAbi, 'constructor');
@@ -176,7 +175,7 @@ export function getProgram(log: LogFn, debugLogger: DebugLogger): Command {
       debugLogger(`Input arguments: ${options.args.map((x: any) => `"${x}"`).join(', ')}`);
       const args = encodeArgs(options.args, constructorAbi!.parameters);
       debugLogger(`Encoded arguments: ${args.join(', ')}`);
-      const tx = deployer.deploy(...args).send({ contractAddressSalt: salt });
+      const tx = deployer.deploy(...args).send({ contractAddressSalt: options.salt });
       debugLogger(`Deploy tx sent with hash ${await tx.getTxHash()}`);
       const deployed = await tx.wait();
       log(`\nContract deployed at ${deployed.contractAddress!.toString()}\n`);

yarn-project/cli/src/test/utils.test.ts

@@ -1,10 +1,11 @@
 import { AztecAddress, Fr } from '@aztec/aztec.js';
 import { AztecRPC, CompleteAddress } from '@aztec/types';
 
+import { InvalidArgumentError } from 'commander';
 import { MockProxy, mock } from 'jest-mock-extended';
 
 import { encodeArgs } from '../encoding.js';
-import { getTxSender } from '../utils.js';
+import { getSaltFromHexString, getTxSender, stripLeadingHex } from '../utils.js';
 import { mockContractAbi } from './mocks.js';
 
 describe('CLI Utils', () => {
@@ -128,4 +129,34 @@ describe('CLI Utils', () => {
       'Invalid value passed for integerParam. Could not parse foo as an integer.',
     );
   });
+
+  describe('stripLeadingHex', () => {
+    it.each([
+      ['0x1', '1'],
+      ['1', '1'],
+      ['0x00', '00'],
+      ['00', '00'],
+    ])('removes optional leading hex', (hex, expected) => {
+      expect(stripLeadingHex(hex)).toEqual(expected);
+    });
+  });
+
+  describe('getSaltFromHex', () => {
+    it.each([
+      ['0', Fr.ZERO],
+      ['0x0', Fr.ZERO],
+      ['00', Fr.ZERO],
+      ['1', new Fr(1)],
+      ['0x1', new Fr(1)],
+      ['0x01', new Fr(1)],
+      ['0xa', new Fr(0xa)],
+      ['fff', new Fr(0xfff)],
+    ])('correctly generates salt from a hex string', (hex, expected) => {
+      expect(getSaltFromHexString(hex)).toEqual(expected);
+    });
+
+    it.each(['foo', '', ' ', ' 0x1', '01foo', 'foo1', '0xfoo'])('throws an error for invalid hex strings', str => {
+      expect(() => getSaltFromHexString(str)).toThrow(InvalidArgumentError);
+    });
+  });
 });

yarn-project/cli/src/utils.ts

@@ -1,8 +1,9 @@
-import { AztecAddress, AztecRPC } from '@aztec/aztec.js';
+import { AztecAddress, AztecRPC, Fr } from '@aztec/aztec.js';
 import { createEthereumChain, deployL1Contracts } from '@aztec/ethereum';
 import { ContractAbi } from '@aztec/foundation/abi';
 import { DebugLogger, LogFn } from '@aztec/foundation/log';
 
+import { InvalidArgumentError } from 'commander';
 import fs from 'fs';
 import { mnemonicToAccount, privateKeyToAccount } from 'viem/accounts';
 
@@ -141,3 +142,36 @@ export async function prepTx(
 
   return { contractAddress, functionArgs, contractAbi };
 }
+
+/**
+ * Removes the leading 0x from a hex string. If no leading 0x is found the string is returned unchanged.
+ * @param hex - A hex string
+ * @returns A new string with leading 0x removed
+ */
+export const stripLeadingHex = (hex: string) => {
+  if (hex.length > 2 && hex.startsWith('0x')) {
+    return hex.substring(2);
+  }
+  return hex;
+};
+
+/**
+ * Parses a hex encoded string to an Fr integer to be used as salt
+ * @param str - Hex encoded string
+ * @returns A integer to be used as salt
+ */
+export function getSaltFromHexString(str: string): Fr {
+  const hex = stripLeadingHex(str);
+
+  // ensure it's a hex string
+  if (!hex.match(/^[0-9a-f]+$/i)) {
+    throw new InvalidArgumentError('Invalid hex string');
+  }
+
+  // pad it so that we may read it as a buffer.
+  // Buffer needs _exactly_ two hex characters per byte
+  const padded = hex.length % 2 === 1 ? '0' + hex : hex;
+
+  // finally, turn it into an integer
+  return Fr.fromBuffer(Buffer.from(padded, 'hex'));
+}