Merge the develop branch into the master branch, v1.2.0-rc1

This merge contains the following set of changes:
  - Fix issues with stats counters (#76)

src/zkbob/ZkBobPool.sol

@@ -190,7 +190,7 @@ abstract contract ZkBobPool is IZkBobPool, EIP1967Admin, Ownable, Parameters, Zk
      * Single transact() call performs either deposit, withdrawal or shielded transfer operation.
      */
     function transact() external onlyOperator {
-        address user;
+        address user = msg.sender;
         uint256 txType = _tx_type();
         if (txType == 0) {
             user = _deposit_spender();
@@ -200,6 +200,12 @@ abstract contract ZkBobPool is IZkBobPool, EIP1967Admin, Ownable, Parameters, Zk
             user = _memo_permit_holder();
         }
         int256 transfer_token_delta = _transfer_token_amount();
+        // For private transfers, operator can receive any fee amount. As receiving a fee is basically a withdrawal,
+        // we should consider operator's tier withdrawal limits respectfully.
+        // For deposits, fee transfers can be left unbounded, since they are paid from the deposits themselves,
+        // not from the pool funds.
+        // For withdrawals, withdrawal amount that is checked against limits for specific user is already inclusive
+        // of operator's fee, thus there is no need to consider it separately.
         (,, uint256 txCount) = _recordOperation(user, transfer_token_delta);
 
         uint256 nullifier = _transfer_nullifier();
@@ -291,7 +297,7 @@ abstract contract ZkBobPool is IZkBobPool, EIP1967Admin, Ownable, Parameters, Zk
         (uint256 total, uint256 totalFee, uint256 hashsum, bytes memory message) =
             direct_deposit_queue.collect(_indices, _out_commit);
 
-        uint256 txCount = _processDirectDepositBatch(total);
+        (,, uint256 txCount) = _recordOperation(address(0), int256(total));
         uint256 _pool_index = txCount << 7;
 
         // verify that _out_commit corresponds to zero output account + 16 chosen notes + 111 empty notes

src/zkbob/utils/ZkBobAccounting.sol

@@ -203,6 +203,13 @@ contract ZkBobAccounting is KycProvidersManagerStorage {
     }
 
     function _processTVLChange(Slot1 memory s1, address _user, int256 _txAmount) internal {
+        // short path for direct deposits batch processing
+        if (_user == address(0) && _txAmount > 0) {
+            slot1.tvl += uint72(uint256(_txAmount));
+
+            return;
+        }
+
         uint16 curDay = uint16(block.timestamp / SLOT_DURATION / DAY_SLOTS);
 
         UserStats memory us = userStats[_user];
@@ -288,11 +295,6 @@ contract ZkBobAccounting is KycProvidersManagerStorage {
         userStats[_user] = us;
     }
 
-    function _processDirectDepositBatch(uint256 _totalAmount) internal returns (uint256) {
-        slot1.tvl += uint72(_totalAmount);
-        return slot0.txCount++;
-    }
-
     function _resetDailyLimits(uint8 _tier) internal {
         delete tiers[_tier].stats;
     }

test/zkbob/ZkBobPool.t.sol

@@ -153,7 +153,7 @@ abstract contract AbstractZkBobPoolTest is AbstractForkTest {
         bytes memory data1 = _encodePermitDeposit(int256(0.5 ether / D), 0.01 ether / D);
         _transact(data1);
 
-        bytes memory data2 = _encodeTransfer();
+        bytes memory data2 = _encodeTransfer(0.01 ether / D);
         _transact(data2);
 
         vm.prank(user3);
@@ -170,7 +170,7 @@ abstract contract AbstractZkBobPoolTest is AbstractForkTest {
 
         assertEq(pool.pool_index(), 128);
 
-        bytes memory data2 = _encodeTransfer();
+        bytes memory data2 = _encodeTransfer(0.01 ether / D);
         _transact(data2);
 
         assertEq(pool.pool_index(), 256);
@@ -256,7 +256,7 @@ abstract contract AbstractZkBobPoolTest is AbstractForkTest {
             _transact(data);
         }
 
-        bytes memory data2 = _encodeTransfer();
+        bytes memory data2 = _encodeTransfer(0.01 ether / D);
         _transact(data2);
 
         vm.prank(user3);
@@ -559,6 +559,29 @@ abstract contract AbstractZkBobPoolTest is AbstractForkTest {
         }
     }
 
+    function testOperatorCannotAvoidWithdrawalLimit() public {
+        deal(token, user1, 1_000_000 ether / D);
+
+        pool.setLimits(
+            0, 1_000_000 ether / D, 500_000 ether / D, 500_000 ether / D, 500_000 ether / D, 500_000 ether / D, 0, 0
+        );
+        bytes memory data1 = _encodePermitDeposit(int256(250_000 ether / D), 0.01 ether / D);
+        _transact(data1);
+        pool.setLimits(
+            0, 1_000_000 ether / D, 100_000 ether / D, 100_000 ether / D, 10_000 ether / D, 10_000 ether / D, 0, 0
+        );
+        bytes memory data2 = _encodeTransfer(200_000 ether / D);
+        _transactReverted(data2, "ZkBobAccounting: daily withdrawal cap exceeded");
+
+        bytes memory data3 = _encodeTransfer(20_000 ether / D);
+        _transact(data3);
+
+        vm.prank(user3);
+        pool.withdrawFee(user2, user3);
+        assertEq(IERC20(token).balanceOf(user3), 20_000.01 ether / D);
+        assertEq(pool.getLimitsFor(user2).dailyWithdrawalCapUsage, 20_000 ether / D / denominator);
+    }
+
     function _encodeDeposit(int256 _amount, uint256 _fee) internal returns (bytes memory) {
         bytes32 nullifier = bytes32(_randFR());
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(pk1, ECDSA.toEthSignedMessageHash(nullifier));
@@ -601,21 +624,14 @@ abstract contract AbstractZkBobPoolTest is AbstractForkTest {
         );
     }
 
-    function _encodeTransfer() internal returns (bytes memory) {
+    function _encodeTransfer(uint256 _fee) internal returns (bytes memory) {
         bytes memory data = abi.encodePacked(
-            ZkBobPool.transact.selector,
-            _randFR(),
-            _randFR(),
-            uint48(0),
-            uint112(0),
-            -int64(uint64(0.01 ether / D / denominator))
+            ZkBobPool.transact.selector, _randFR(), _randFR(), uint48(0), uint112(0), -int64(uint64(_fee / denominator))
         );
         for (uint256 i = 0; i < 17; i++) {
             data = abi.encodePacked(data, _randFR());
         }
-        return abi.encodePacked(
-            data, uint16(1), uint16(44), uint64(0.01 ether / D / denominator), bytes4(0x01000000), _randFR()
-        );
+        return abi.encodePacked(data, uint16(1), uint16(44), uint64(_fee / denominator), bytes4(0x01000000), _randFR());
     }
 
     function _transact(bytes memory _data) internal {