Disable/Enable rate limit for erc20 tokens (#311)

- closes #309

.changeset/smooth-carrots-visit.md

@@ -0,0 +1,5 @@
+---
+'@fuel-bridge/solidity-contracts': minor
+---
+
+add rate limit disabling/re-enabling

packages/integration-tests/tests/bridge_erc20.ts

@@ -165,6 +165,10 @@ describe('Bridging ERC20 tokens', async function () {
         RATE_LIMIT_DURATION
       );
 
+    await env.eth.fuelERC20Gateway
+      .connect(env.eth.deployer)
+      .updateRateLimitStatus(eth_testTokenAddress, true);
+
     const { value: expectedGatewayContractId } = await fuel_bridge.functions
       .bridged_token_gateway()
       .addContracts([fuel_bridge, fuel_bridgeImpl])

packages/integration-tests/tests/bridge_mainnet_tokens.ts

@@ -221,6 +221,10 @@ describe('Bridge mainnet tokens', function () {
               rateLimitAmount.toString(),
               RATE_LIMIT_DURATION
             );
+
+          await env.eth.fuelERC20Gateway
+            .connect(env.eth.deployer)
+            .updateRateLimitStatus(tokenAddress, true);
         }
       );
 

packages/solidity-contracts/contracts/messaging/gateway/FuelERC20Gateway/FuelERC20GatewayV4.sol

@@ -48,6 +48,9 @@ contract FuelERC20GatewayV4 is
     /// @dev Emitted when rate limit is reset
     event RateLimitUpdated(address indexed tokenAddress, uint256 amount);
 
+    /// @dev Emitted when rate limit is enabled/disabled
+    event RateLimitStatusUpdated(address indexed tokenAddress, bool status);
+
     enum MessageType {
         DEPOSIT_TO_ADDRESS,
         DEPOSIT_TO_CONTRACT,
@@ -89,6 +92,11 @@ contract FuelERC20GatewayV4 is
     /// @notice The eth withdrawal limit amount for each token.
     mapping(address => uint256) public limitAmount;
 
+    /// @notice Flag to indicate rate limit status for each token, whether disabled or enabled.
+    // if `true` it is enabled
+    // if `false` it is disabled
+    mapping(address => bool) public rateLimitStatus;
+
 	/// @notice disabling initialization
     /// @custom:oz-upgrades-unsafe-allow constructor
     constructor() {
@@ -175,6 +183,17 @@ contract FuelERC20GatewayV4 is
 
         emit RateLimitUpdated(_token, _amount);
     }
+
+    /**
+     * @notice updates rate limit status by disabling/re-enabling rate limit.
+     * @param _token The token address to update rate limit status for.
+     * @param _rateLimitStatus bool flag to disable or re-enable rate limit.
+     */
+    function updateRateLimitStatus(address _token, bool _rateLimitStatus) external onlyRole(SET_RATE_LIMITER_ROLE) {
+        rateLimitStatus[_token] = _rateLimitStatus;
+
+        emit RateLimitStatusUpdated(_token, _rateLimitStatus);
+    }
 
     //////////////////////
     // Public Functions //
@@ -287,8 +306,9 @@ contract FuelERC20GatewayV4 is
         uint8 decimals = _getTokenDecimals(tokenAddress);
         uint256 amount = _adjustWithdrawalDecimals(decimals, l2BurntAmount);
 
-        // rate limit check only if rate limit is initialized
-        if (currentPeriodEnd[tokenAddress] != 0) _addWithdrawnAmount(tokenAddress, amount);
+        // rate limit check is only performed when it is enabled
+        // if the rate limit has not been initialised then the tx will revert with `RateLimitExceeded()`
+        if (rateLimitStatus[tokenAddress]) _addWithdrawnAmount(tokenAddress, amount);
 
         //reduce deposit balance and transfer tokens (math will underflow if amount is larger than allowed)
         _deposits[tokenAddress] = _deposits[tokenAddress] - l2BurntAmount;

packages/solidity-contracts/test/behaviors/erc20GatewayV4.behavior.test.ts

@@ -1039,7 +1039,7 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
             const rateLimitAmount =
               RATE_LIMIT_AMOUNT / 10 ** (STANDARD_TOKEN_DECIMALS - decimals);
 
-            const tx = erc20Gateway
+            let tx = erc20Gateway
               .connect(deployer)
               .resetRateLimitAmount(
                 token.getAddress(),
@@ -1050,6 +1050,14 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
             await expect(tx)
               .to.emit(erc20Gateway, 'RateLimitUpdated')
               .withArgs(token.getAddress(), rateLimitAmount.toString());
+
+            tx = erc20Gateway
+              .connect(deployer)
+              .updateRateLimitStatus(token, true);
+
+            await expect(tx)
+              .to.emit(erc20Gateway, 'RateLimitStatusUpdated')
+              .withArgs(token.getAddress(), true);
           });
 
           it('does not update rate limit vars when it is not initialized', async () => {
@@ -1133,6 +1141,13 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
                 RATE_LIMIT_DURATION
               );
 
+            await erc20Gateway
+              .connect(deployer)
+              .updateRateLimitStatus(token, true);
+
+            const status = await erc20Gateway.rateLimitStatus(token);
+            expect(status).to.be.true;
+
             const amount = parseUnits(
               random(0.01, 1, true).toFixed(decimals),
               Number(decimals)
@@ -1238,6 +1253,10 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
                 RATE_LIMIT_DURATION
               );
 
+            await erc20Gateway
+              .connect(deployer)
+              .updateRateLimitStatus(token, true);
+
             const amount = parseUnits('10', Number(decimals));
             const recipient = randomBytes32();
 
@@ -1273,6 +1292,7 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
 
             const currentWithdrawnAmountBeforeSettingLimit =
               await erc20Gateway.currentPeriodAmount(token.getAddress());
+
             rateLimitAmount =
               RATE_LIMIT_AMOUNT /
               5 /
@@ -1289,6 +1309,10 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
             const currentWithdrawnAmountAfterSettingLimit =
               await erc20Gateway.currentPeriodAmount(token.getAddress());
 
+            expect(currentWithdrawnAmountAfterSettingLimit).to.be.equal(
+              withdrawAmount
+            );
+
             expect(currentWithdrawnAmountAfterSettingLimit).to.be.equal(
               currentWithdrawnAmountBeforeSettingLimit
             );
@@ -1340,6 +1364,10 @@ export function behavesLikeErc20GatewayV4(fixture: () => Promise<Env>) {
                 RATE_LIMIT_DURATION
               );
 
+            await erc20Gateway
+              .connect(deployer)
+              .updateRateLimitStatus(token, true);
+
             const amount = parseUnits('10', Number(decimals));
             const recipient = randomBytes32();
 

packages/solidity-contracts/test/fuelChainState.ts

@@ -105,7 +105,7 @@ describe('Fuel Chain State', async () => {
       ).to.be.revertedWithCustomError(FuelChainState, 'TimeToFinalizeTooLarge');
     });
 
-    it('reverts if time to finalise is more than circularBufferSizeInSeconds', async () => {
+    it('reverts if commit cooldown period is more than circularBufferSizeInSeconds', async () => {
       await expect(
         upgrades.deployProxy(FuelChainState, [], {
           initializer: 'initialize',