v0.7.1

src/solidity/Fees.sol

@@ -1,37 +1,29 @@
 // SPDX-License-Identifier: Apache-2.0.
 pragma solidity ^0.8.0;
 
+// Estimate cost for L1-L2 message handler.
 uint256 constant DEPOSIT_FEE_GAS = 20000;
 uint256 constant DEPLOYMENT_FEE_GAS = 100000;
-uint256 constant MIN_FEE_MARGIN = 100000;
-uint256 constant MAX_FEE_MARGIN = 10**14;
 
-library Fees {
-    function estimateDepositFee() internal view returns (uint256) {
-        return DEPOSIT_FEE_GAS * block.basefee;
-    }
+// We don't have a solid way to gauge block gas price
+// (block.basefee cannot be used).
+uint256 constant DEFAULT_WEI_PER_GAS = 5 * 10**9;
 
-    function estimateEnrollmentFee() internal view returns (uint256) {
-        return DEPLOYMENT_FEE_GAS * block.basefee;
-    }
+abstract contract Fees {
+    // Effectively no minimum fee on testnet.
+    uint256 immutable MIN_FEE = (block.chainid == 1) ? 10**12 : 1;
+    uint256 constant MAX_FEE = 10**16;
 
-    function checkDepositFee(uint256 feeWei) internal view {
-        checkFee(feeWei, estimateDepositFee());
+    function estimateDepositFee() internal pure returns (uint256) {
+        return DEPOSIT_FEE_GAS * DEFAULT_WEI_PER_GAS;
     }
 
-    function checkEnrollmentFee(uint256 feeWei) internal view {
-        checkFee(feeWei, estimateEnrollmentFee());
+    function estimateEnrollmentFee() internal pure returns (uint256) {
+        return DEPLOYMENT_FEE_GAS * DEFAULT_WEI_PER_GAS;
     }
 
-    /*
-      The fee should be within margins from the estimated fee:
-      max(5, estimate/2 - MIN_FEE_MARGIN) <= fee <= 2*estimate + MAX_FEE_MARGIN.
-    */
-    function checkFee(uint256 feeWei, uint256 feeEstimate) internal pure {
-        uint256 minFee = feeEstimate >> 1;
-        minFee = (minFee < MIN_FEE_MARGIN + 5) ? 5 : (minFee - MIN_FEE_MARGIN);
-        uint256 maxFee = MAX_FEE_MARGIN + (feeEstimate << 1);
-        require(feeWei >= minFee, "INSUFFICIENT_FEE_VALUE");
-        require(feeWei <= maxFee, "FEE_VALUE_TOO_HIGH");
+    function checkFee(uint256 feeWei) internal view {
+        require(feeWei >= MIN_FEE, "INSUFFICIENT_FEE_VALUE");
+        require(feeWei <= MAX_FEE, "FEE_VALUE_TOO_HIGH");
     }
 }

src/solidity/StarknetERC20Bridge.sol

@@ -5,6 +5,6 @@ import "src/solidity/LegacyBridge.sol";
 
 contract StarknetERC20Bridge is LegacyBridge {
     function identify() external pure override returns (string memory) {
-        return "StarkWare_StarknetERC20Bridge_2.0_3";
+        return "StarkWare_StarknetERC20Bridge_2.0_4";
     }
 }

src/solidity/StarknetEthBridge.sol

@@ -9,7 +9,7 @@ contract StarknetEthBridge is LegacyBridge {
     using Addresses for address;
 
     function identify() external pure override returns (string memory) {
-        return "StarkWare_StarknetEthBridge_2.0_3";
+        return "StarkWare_StarknetEthBridge_2.0_4";
     }
 
     function acceptDeposit(
@@ -19,7 +19,7 @@ contract StarknetEthBridge is LegacyBridge {
         // Make sure msg.value is enough to cover amount. The remaining value is fee.
         require(msg.value >= amount, "INSUFFICIENT_VALUE");
         uint256 fee = msg.value - amount;
-        Fees.checkDepositFee(fee);
+        Fees.checkFee(fee);
         // The msg.value was already credited to this contract. Fee will be passed to Starknet.
         require(address(this).balance - fee <= getMaxTotalBalance(ETH), "MAX_BALANCE_EXCEEDED");
         return fee;

src/solidity/StarknetTokenBridge.sol

@@ -24,6 +24,7 @@ contract StarknetTokenBridge is
     IStarkgateBridge,
     IStarkgateService,
     Identity,
+    Fees,
     StarknetTokenStorage,
     ProxySupport
 {
@@ -90,7 +91,7 @@ contract StarknetTokenBridge is
     uint256 constant DEPOSIT_MESSAGE_FIXED_SIZE = 1;
 
     function identify() external pure virtual returns (string memory) {
-        return "StarkWare_StarknetTokenBridge_2.0_3";
+        return "StarkWare_StarknetTokenBridge_2.0_4";
     }
 
     function validateInitData(bytes calldata data) internal view virtual override {
@@ -139,17 +140,17 @@ contract StarknetTokenBridge is
         _;
     }
 
-    function estimateDepositFeeWei() external view returns (uint256) {
+    function estimateDepositFeeWei() external pure returns (uint256) {
         return Fees.estimateDepositFee();
     }
 
-    function estimateEnrollmentFeeWei() external view returns (uint256) {
+    function estimateEnrollmentFeeWei() external pure returns (uint256) {
         return Fees.estimateEnrollmentFee();
     }
 
     // Virtual functions.
     function acceptDeposit(address token, uint256 amount) internal virtual returns (uint256) {
-        Fees.checkDepositFee(msg.value);
+        Fees.checkFee(msg.value);
         uint256 currentBalance = IERC20(token).balanceOf(address(this));
         require(currentBalance + amount <= getMaxTotalBalance(token), "MAX_BALANCE_EXCEEDED");
         Transfers.transferIn(token, msg.sender, amount);
@@ -429,7 +430,7 @@ contract StarknetTokenBridge is
 
     function sendDeployMessage(address token) internal returns (bytes32) {
         require(l2TokenBridge() != 0, "L2_BRIDGE_NOT_SET");
-        Fees.checkEnrollmentFee(msg.value);
+        Fees.checkFee(msg.value);
 
         (bytes32 deploymentMsgHash, ) = messagingContract().sendMessageToL2{value: msg.value}(
             l2TokenBridge(),

src/solidity/conftest.py

@@ -22,6 +22,7 @@
     StarknetTokenBridgeTester,
     StarknetERC20BridgeTester,
     SelfRemoveTester,
+    FeeTester,
 )
 
 DYNAMIC_FEE = -1
@@ -191,6 +192,11 @@ def regular_user(eth_test_utils: EthTestUtils) -> EthContract:
     return eth_test_utils.accounts[3]
 
 
+@pytest.fixture
+def fee_tester(governor: EthAccount) -> EthContract:
+    return governor.deploy(FeeTester)
+
+
 @pytest.fixture
 def mock_erc20_contract(governor: EthAccount) -> EthContract:
     erc20_contract = governor.deploy(TestERC20)

src/solidity/files_to_compile.txt

@@ -12,3 +12,4 @@ starkware/solidity/test_contracts/TestERC20.sol
 starkware/solidity/upgrade/Proxy.sol
 starkware/starknet/testing/MockStarknetMessaging.sol
 src/solidity/StarkgateUpgradeAssistExternalInitializer.sol
+src/solidity/test_contracts/TestFees.sol

src/solidity/legacy_token_bridge_test.py

@@ -1,6 +1,5 @@
 import pytest
 from web3 import Web3
-from starkware.cairo.lang.cairo_constants import DEFAULT_PRIME
 from starkware.eth.eth_test_utils import EthContract, EthRevertException, EthTestUtils, EthAccount
 from solidity.conftest import (
     add_implementation_and_upgrade,
@@ -11,16 +10,8 @@
     deploy_proxy,
     messaging_contract,
     mock_erc20_contract,
-    StarknetTokenBridgeWrapper,
-    EthBridgeWrapper,
-    StarknetERC20BridgeWrapper,
-    TokenBridgeWrapper,
     L1_TOKEN_ADDRESS_OF_ETH,
-    L2_TOKEN_CONTRACT,
     MAX_UINT,
-    HANDLE_TOKEN_DEPOSIT_SELECTOR,
-    HANDLE_DEPOSIT_WITH_MESSAGE_SELECTOR,
-    HANDLE_TOKEN_DEPLOYMENT_SELECTOR,
     TOKEN_ADDRESS,
     UpgradeAssistEIC,
     StarknetTokenBridge,
@@ -48,6 +39,8 @@
 WITHDRAW_AMOUNT = 3
 MESSAGE_CANCEL_DELAY = 1000
 MAX_TVL = 496351
+MAX_FEE = 10**16
+MIN_FEE = 10**12
 
 
 @pytest.fixture(scope="session")
@@ -136,6 +129,23 @@ def legacy_tester_erc20_new_proxy_bridge(
     )
 
 
+def test_fee_values(fee_tester):
+    with pytest.raises(EthRevertException, match="INSUFFICIENT_FEE_VALUE"):
+        fee_tester.testCheckFee.call(0)
+
+    for valid_fee in [MIN_FEE, MAX_FEE]:
+        fee_tester.testCheckFee.call(valid_fee)
+
+    deposit_fee = fee_tester.estimateDepositFeeWei.call()
+    assert MIN_FEE * 10 < deposit_fee < MAX_FEE // 10
+
+    enrollment_fee = fee_tester.estimateEnrollmentFeeWei.call()
+    assert MIN_FEE * 10 < enrollment_fee < MAX_FEE // 10
+
+    with pytest.raises(EthRevertException, match="FEE_VALUE_TOO_HIGH"):
+        fee_tester.testCheckFee.call(1 + MAX_FEE)
+
+
 def test_erc20_bridge_deposit_cancel_upgrade(
     governor: EthAccount,
     mock_erc20_contract: EthContract,

src/solidity/test_contracts.py

@@ -5,3 +5,4 @@
 StarknetERC20BridgeTester = load_contract("StarknetERC20BridgeTester")
 SelfRemoveTester = load_contract("SelfRemoveTester")
 StarkgateRegistry = load_contract("StarkgateRegistry")
+FeeTester = load_contract("TestFees")

src/solidity/test_contracts/TestFees.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0.
+pragma solidity ^0.8.0;
+
+import "src/solidity/Fees.sol";
+
+contract TestFees is Fees {
+    function estimateDepositFeeWei() external pure returns (uint256) {
+        return Fees.estimateDepositFee();
+    }
+
+    function estimateEnrollmentFeeWei() external pure returns (uint256) {
+        return Fees.estimateEnrollmentFee();
+    }
+
+    function testCheckFee(uint256 feeWei) external view {
+        Fees.checkFee(feeWei);
+    }
+}

src/solidity/token_bridge_test.py

@@ -191,18 +191,17 @@ def test_deposit_l2_token_contract_not_set(token_bridge_wrapper: TokenBridgeWrap
 def test_deposit_fee_too_low(token_bridge_wrapper: TokenBridgeWrapper):
     setup_contracts(token_bridge_wrapper=token_bridge_wrapper)
     with pytest.raises(EthRevertException, match="INSUFFICIENT_FEE_VALUE"):
-        token_bridge_wrapper.deposit(amount=DEPOSIT_AMOUNT, l2_recipient=L2_RECIPIENT, fee=1)
+        token_bridge_wrapper.deposit(amount=DEPOSIT_AMOUNT, l2_recipient=L2_RECIPIENT, fee=0)
 
     with pytest.raises(EthRevertException, match="INSUFFICIENT_FEE_VALUE"):
         token_bridge_wrapper.deposit(
-            amount=DEPOSIT_AMOUNT, l2_recipient=L2_RECIPIENT, fee=1, message=MESSAGE
+            amount=DEPOSIT_AMOUNT, l2_recipient=L2_RECIPIENT, fee=0, message=MESSAGE
         )
 
 
 def test_deposit_fee_too_high(token_bridge_wrapper: TokenBridgeWrapper):
     setup_contracts(token_bridge_wrapper=token_bridge_wrapper)
-    base_fee = token_bridge_wrapper.contract.estimateDepositFeeWei.call()
-    too_high_fee = 2 * base_fee + 2 * 10**14
+    too_high_fee = 2 + 10**16
     with pytest.raises(EthRevertException, match="FEE_VALUE_TOO_HIGH"):
         token_bridge_wrapper.deposit(
             amount=DEPOSIT_AMOUNT, l2_recipient=L2_RECIPIENT, fee=too_high_fee