feat: native fee payment (#4543)

This PR adds a gas payment contract.

---------

Co-authored-by: Rahul Kothari <rahul.kothari.201@gmail.com>
Co-authored-by: Mitchell Tracy <mitchell@aztecprotocol.com>

.circleci/config.yml

@@ -895,6 +895,18 @@ jobs:
       - run:
           name: "Test"
           command: AVM_ENABLED=1 cond_spot_run_compose end-to-end 4 ./scripts/docker-compose.yml TEST=e2e_avm_simulator.test.ts
+
+  e2e-fees:
+    docker:
+      - image: aztecprotocol/alpine-build-image
+    resource_class: small
+    steps:
+      - *checkout
+      - *setup_env
+      - run:
+          name: "Test"
+          command: cond_spot_run_compose end-to-end 4 ./scripts/docker-compose.yml TEST=e2e_fees.test.ts
+
   pxe:
     docker:
       - image: aztecprotocol/alpine-build-image
@@ -916,7 +928,7 @@ jobs:
       - run:
           name: "Test"
           command: cond_spot_run_compose end-to-end 4 ./scripts/docker-compose.yml TEST=cli_docs_sandbox.test.ts
-   
+
   e2e-docs-examples:
     docker:
       - image: aztecprotocol/alpine-build-image
@@ -926,7 +938,7 @@ jobs:
       - *setup_env
       - run:
           name: "Test"
-          command: AVM_ENABLED=1 cond_spot_run_compose end-to-end 4 ./scripts/docker-compose.yml TEST=docs_examples_test.ts   
+          command: AVM_ENABLED=1 cond_spot_run_compose end-to-end 4 ./scripts/docker-compose.yml TEST=docs_examples_test.ts
 
   guides-writing-an-account-contract:
     docker:
@@ -1362,6 +1374,7 @@ workflows:
       - e2e-browser: *e2e_test
       - e2e-card-game: *e2e_test
       - e2e-avm-simulator: *e2e_test
+      - e2e-fees: *e2e_test
       - pxe: *e2e_test
       - cli-docs-sandbox: *e2e_test
       - e2e-docs-examples: *e2e_test
@@ -1406,6 +1419,7 @@ workflows:
             - e2e-browser
             - e2e-card-game
             - e2e-avm-simulator
+            - e2e-fees
             - pxe
             - boxes-blank
             - boxes-blank-react

noir-projects/noir-contracts/Nargo.toml

@@ -14,6 +14,7 @@ members = [
     "contracts/easy_private_voting_contract",
     "contracts/ecdsa_account_contract",
     "contracts/escrow_contract",
+    "contracts/gas_token_contract",
     "contracts/import_test_contract",
     "contracts/inclusion_proofs_contract",
     "contracts/lending_contract",

noir-projects/noir-contracts/contracts/gas_token_contract/Nargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "gas_token_contract"
+authors = [""]
+compiler_version = ">=0.18.0"
+type = "contract"
+
+[dependencies]
+aztec = { path = "../../../aztec-nr/aztec" }
+safe_math = { path = "../../../aztec-nr/safe-math" }
+authwit = { path = "../../../aztec-nr/authwit" }

noir-projects/noir-contracts/contracts/gas_token_contract/src/fee.nr

@@ -0,0 +1,6 @@
+use dep::safe_math::SafeU120;
+use dep::aztec::context::PublicContext;
+
+pub fn calculate_fee(_context: PublicContext) -> SafeU120 {
+    SafeU120::new(1)
+}

noir-projects/noir-contracts/contracts/gas_token_contract/src/main.nr

@@ -0,0 +1,63 @@
+mod fee;
+
+contract GasToken {
+    use dep::aztec::protocol_types::{abis::function_selector::FunctionSelector, address::AztecAddress};
+    use dep::aztec::{hash::{compute_secret_hash}, state_vars::{public_state::PublicState, map::Map}};
+
+    use dep::safe_math::SafeU120;
+
+    use crate::fee::calculate_fee;
+
+    struct Storage {
+        balances: Map<AztecAddress, PublicState<SafeU120>>,
+    }
+
+    #[aztec(private)]
+    fn constructor() {}
+
+    #[aztec(public)]
+    fn redeem_bridged_balance(amount: Field) {
+        // mock
+        let amount_u120 = SafeU120::new(amount);
+        let new_balance = storage.balances.at(context.msg_sender()).read().add(amount_u120);
+        storage.balances.at(context.msg_sender()).write(new_balance);
+    }
+
+    #[aztec(public)]
+    fn check_balance(fee_limit: Field) {
+        let fee_limit_u120 = SafeU120::new(fee_limit);
+        assert(storage.balances.at(context.msg_sender()).read().ge(fee_limit_u120), "Balance too low");
+    }
+
+    #[aztec(public)]
+    fn pay_fee(fee_limit: Field) -> Field {
+        let fee_limit_u120 = SafeU120::new(fee_limit);
+        let fee = calculate_fee(context);
+        assert(fee.le(fee_limit_u120), "Fee too high");
+
+        let sender_new_balance = storage.balances.at(context.msg_sender()).read().sub(fee);
+        storage.balances.at(context.msg_sender()).write(sender_new_balance);
+
+        let recipient_new_balance = storage.balances.at(context.fee_recipient()).read().add(fee);
+        storage.balances.at(context.fee_recipient()).write(recipient_new_balance);
+
+        let rebate = fee_limit_u120.sub(fee);
+        rebate.value as Field
+    }
+
+    // utility function for testing
+    unconstrained fn balance_of(owner: AztecAddress) -> pub Field {
+        storage.balances.at(owner).read().value as Field
+    }
+
+    // TODO: remove this placeholder once https://github.com/AztecProtocol/aztec-packages/issues/2918 is implemented
+    unconstrained fn compute_note_hash_and_nullifier(
+        contract_address: AztecAddress,
+        nonce: Field,
+        storage_slot: Field,
+        note_type_id: Field,
+        serialized_note: [Field; 0]
+    ) -> pub [Field; 4] {
+        [0, 0, 0, 0]
+    }
+}

yarn-project/aztec.js/src/contract/base_contract_interaction.ts

@@ -1,5 +1,6 @@
 import { PXE, Tx, TxExecutionRequest } from '@aztec/circuit-types';
 
+import { FeeOptions } from '../account/interface.js';
 import { SentTx } from './sent_tx.js';
 
 /**
@@ -11,6 +12,11 @@ export type SendMethodOptions = {
    * Wether to skip the simulation of the public part of the transaction.
    */
   skipPublicSimulation?: boolean;
+
+  /**
+   * The fee options for the transaction.
+   */
+  fee?: FeeOptions;
 };
 
 /**

yarn-project/aztec.js/src/contract/batch_call.ts

@@ -1,7 +1,7 @@
 import { FunctionCall, TxExecutionRequest } from '@aztec/circuit-types';
 
 import { Wallet } from '../account/index.js';
-import { BaseContractInteraction } from './base_contract_interaction.js';
+import { BaseContractInteraction, SendMethodOptions } from './base_contract_interaction.js';
 
 /** A batch of function calls to be sent as a single transaction through a wallet. */
 export class BatchCall extends BaseContractInteraction {
@@ -12,11 +12,12 @@ export class BatchCall extends BaseContractInteraction {
   /**
    * Create a transaction execution request that represents this batch, encoded and authenticated by the
    * user's wallet, ready to be simulated.
+   * @param opts - An optional object containing additional configuration for the transaction.
    * @returns A Promise that resolves to a transaction instance.
    */
-  public async create(): Promise<TxExecutionRequest> {
+  public async create(opts?: SendMethodOptions): Promise<TxExecutionRequest> {
     if (!this.txRequest) {
-      this.txRequest = await this.wallet.createTxExecutionRequest(this.calls);
+      this.txRequest = await this.wallet.createTxExecutionRequest(this.calls, opts?.fee);
     }
     return this.txRequest;
   }

yarn-project/aztec.js/src/contract/contract_function_interaction.ts

@@ -38,14 +38,15 @@ export class ContractFunctionInteraction extends BaseContractInteraction {
   /**
    * Create a transaction execution request that represents this call, encoded and authenticated by the
    * user's wallet, ready to be simulated.
+   * @param opts - An optional object containing additional configuration for the transaction.
    * @returns A Promise that resolves to a transaction instance.
    */
-  public async create(): Promise<TxExecutionRequest> {
+  public async create(opts?: SendMethodOptions): Promise<TxExecutionRequest> {
     if (this.functionDao.functionType === FunctionType.UNCONSTRAINED) {
       throw new Error("Can't call `create` on an unconstrained function.");
     }
     if (!this.txRequest) {
-      this.txRequest = await this.wallet.createTxExecutionRequest([this.request()]);
+      this.txRequest = await this.wallet.createTxExecutionRequest([this.request()], opts?.fee);
     }
     return this.txRequest;
   }

yarn-project/aztec.js/src/fee/native_fee_payment_method.ts

@@ -1,17 +1,16 @@
 import { FunctionCall } from '@aztec/circuit-types';
 import { FunctionData } from '@aztec/circuits.js';
 import { FunctionSelector } from '@aztec/foundation/abi';
-import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { Fr } from '@aztec/foundation/fields';
+import { GasTokenAddress } from '@aztec/protocol-contracts/gas-token';
 
 import { FeePaymentMethod } from './fee_payment_method.js';
 
 /**
  * Pay fee directly in the native gas token.
  */
 export class NativeFeePaymentMethod implements FeePaymentMethod {
-  // TODO(fees) replace this with the address of the gas token when that's deployed.
-  static #GAS_TOKEN = AztecAddress.ZERO;
+  static #GAS_TOKEN = GasTokenAddress;
 
   constructor() {}
 

yarn-project/end-to-end/package.json

@@ -38,6 +38,7 @@
     "@aztec/merkle-tree": "workspace:^",
     "@aztec/noir-contracts.js": "workspace:^",
     "@aztec/p2p": "workspace:^",
+    "@aztec/protocol-contracts": "workspace:^",
     "@aztec/pxe": "workspace:^",
     "@aztec/sequencer-client": "workspace:^",
     "@aztec/types": "workspace:^",

yarn-project/end-to-end/src/cli_docs_sandbox.test.ts

@@ -109,6 +109,7 @@ EasyPrivateTokenContractArtifact
 EasyPrivateVotingContractArtifact
 EcdsaAccountContractArtifact
 EscrowContractArtifact
+GasTokenContractArtifact
 ImportTestContractArtifact
 InclusionProofsContractArtifact
 LendingContractArtifact

yarn-project/end-to-end/src/e2e_fees.test.ts

@@ -0,0 +1,66 @@
+import { AztecAddress, ContractDeployer, NativeFeePaymentMethod } from '@aztec/aztec.js';
+import { GasTokenContract, TokenContract } from '@aztec/noir-contracts.js';
+import { getCanonicalGasToken } from '@aztec/protocol-contracts/gas-token';
+
+import { setup } from './fixtures/utils.js';
+
+describe('e2e_fees', () => {
+  let aliceAddress: AztecAddress;
+  let _bobAddress: AztecAddress;
+  let sequencerAddress: AztecAddress;
+  let gasTokenContract: GasTokenContract;
+  let testContract: TokenContract;
+
+  beforeAll(async () => {
+    process.env.PXE_URL = '';
+    const { accounts, aztecNode, wallet } = await setup(3);
+
+    await aztecNode.setConfig({
+      feeRecipient: accounts.at(-1)!.address,
+    });
+    const canonicalGasToken = getCanonicalGasToken();
+    const deployer = new ContractDeployer(canonicalGasToken.artifact, wallet);
+    const { contract } = await deployer
+      .deploy()
+      .send({
+        contractAddressSalt: canonicalGasToken.instance.salt,
+      })
+      .wait();
+
+    gasTokenContract = contract as GasTokenContract;
+    aliceAddress = accounts.at(0)!.address;
+    _bobAddress = accounts.at(1)!.address;
+    sequencerAddress = accounts.at(-1)!.address;
+
+    testContract = await TokenContract.deploy(wallet, aliceAddress, 'Test', 'TEST', 1).send().deployed();
+
+    // Alice gets a balance of 1000 gas token
+    await gasTokenContract.methods.redeem_bridged_balance(1000).send().wait();
+  }, 100_000);
+
+  it('deploys gas token contract at canonical address', () => {
+    expect(gasTokenContract.address).toEqual(getCanonicalGasToken().address);
+  });
+
+  describe('NativeFeePaymentMethod', () => {
+    it('pays out the expected fee to the sequencer', async () => {
+      await testContract.methods
+        .mint_public(aliceAddress, 1000)
+        .send({
+          fee: {
+            maxFee: 1,
+            paymentMethod: new NativeFeePaymentMethod(),
+          },
+        })
+        .wait();
+
+      const [sequencerBalance, aliceBalance] = await Promise.all([
+        gasTokenContract.methods.balance_of(sequencerAddress).view(),
+        gasTokenContract.methods.balance_of(aliceAddress).view(),
+      ]);
+
+      expect(sequencerBalance).toEqual(1n);
+      expect(aliceBalance).toEqual(999n);
+    });
+  });
+});

yarn-project/end-to-end/src/fixtures/utils.ts

@@ -192,6 +192,7 @@ async function setupWithRemoteEnvironment(
   };
   const cheatCodes = CheatCodes.create(config.rpcUrl, pxeClient!);
   const teardown = () => Promise.resolve();
+
   return {
     aztecNode,
     sequencer: undefined,

yarn-project/end-to-end/tsconfig.json

@@ -48,6 +48,9 @@
     {
       "path": "../p2p"
     },
+    {
+      "path": "../protocol-contracts"
+    },
     {
       "path": "../pxe"
     },

yarn-project/protocol-contracts/scripts/copy-contracts.sh

@@ -2,10 +2,14 @@
 set -euo pipefail
 mkdir -p ./src/artifacts
 
-contracts=(contract_class_registerer_contract-ContractClassRegisterer contract_instance_deployer_contract-ContractInstanceDeployer)
+contracts=(
+  contract_class_registerer_contract-ContractClassRegisterer
+  contract_instance_deployer_contract-ContractInstanceDeployer
+  gas_token_contract-GasToken
+)
 
 for contract in "${contracts[@]}"; do
   cp "../noir-contracts.js/artifacts/$contract.json" ./src/artifacts/${contract#*-}.json
 done
 
-yarn run -T prettier -w ./src/artifacts
+yarn run -T prettier -w ./src/artifacts

yarn-project/protocol-contracts/src/gas-token/artifact.ts

@@ -0,0 +1,6 @@
+import { loadContractArtifact } from '@aztec/types/abi';
+import { NoirCompiledContract } from '@aztec/types/noir';
+
+import GasTokenJson from '../artifacts/GasToken.json' assert { type: 'json' };
+
+export const GasTokenArtifact = loadContractArtifact(GasTokenJson as NoirCompiledContract);

yarn-project/protocol-contracts/src/gas-token/index.test.ts

@@ -0,0 +1,8 @@
+import { GasTokenAddress, getCanonicalGasToken } from './index.js';
+
+describe('GasToken', () => {
+  it('returns canonical protocol contract', () => {
+    const contract = getCanonicalGasToken();
+    expect(contract.address.toString()).toEqual(GasTokenAddress.toString());
+  });
+});

yarn-project/protocol-contracts/src/gas-token/index.ts

@@ -0,0 +1,9 @@
+import { ProtocolContract, getCanonicalProtocolContract } from '../protocol_contract.js';
+import { GasTokenArtifact } from './artifact.js';
+
+/** Returns the canonical deployment of the gas token. */
+export function getCanonicalGasToken(): ProtocolContract {
+  return getCanonicalProtocolContract(GasTokenArtifact, 1);
+}
+
+export const GasTokenAddress = getCanonicalGasToken().address;

yarn-project/pxe/src/pxe_service/create_pxe_service.ts

@@ -4,6 +4,7 @@ import { TestKeyStore } from '@aztec/key-store';
 import { AztecLmdbStore } from '@aztec/kv-store/lmdb';
 import { initStoreForRollup } from '@aztec/kv-store/utils';
 import { getCanonicalClassRegisterer } from '@aztec/protocol-contracts/class-registerer';
+import { getCanonicalGasToken } from '@aztec/protocol-contracts/gas-token';
 import { getCanonicalInstanceDeployer } from '@aztec/protocol-contracts/instance-deployer';
 
 import { join } from 'path';
@@ -45,7 +46,7 @@ export async function createPXEService(
   const db = new KVPxeDatabase(await initStoreForRollup(AztecLmdbStore.open(pxeDbPath), l1Contracts.rollupAddress));
 
   const server = new PXEService(keyStore, aztecNode, db, config, logSuffix);
-  await server.addContracts([getCanonicalClassRegisterer(), getCanonicalInstanceDeployer()]);
+  await server.addContracts([getCanonicalClassRegisterer(), getCanonicalInstanceDeployer(), getCanonicalGasToken()]);
 
   await server.start();
   return server;

yarn-project/yarn.lock

@@ -387,6 +387,7 @@ __metadata:
     "@aztec/merkle-tree": "workspace:^"
     "@aztec/noir-contracts.js": "workspace:^"
     "@aztec/p2p": "workspace:^"
+    "@aztec/protocol-contracts": "workspace:^"
     "@aztec/pxe": "workspace:^"
     "@aztec/sequencer-client": "workspace:^"
     "@aztec/types": "workspace:^"