fix: issue-1: precision issue in getPendingDistributionAmount (#78)

Co-authored-by: Benjamin <benjaminxh+github@gmail.com>
PufferFinance · Nov 26, 2024 · e6352a0 · e6352a0
1 parent d6a54d4
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Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/mainnet-contracts/src/PufferRevenueDepositor.sol b/mainnet-contracts/src/PufferRevenueDepositor.sol
@@ -26,6 +26,7 @@ contract PufferRevenueDepositor is
     UUPSUpgradeable
 {
     using EnumerableSet for EnumerableSet.AddressSet;
+    using Math for uint256;
 
     /**
      * @notice The maximum rewards distribution window.
@@ -94,7 +95,7 @@ contract PufferRevenueDepositor is
         uint256 timePassed = block.timestamp - $.lastDepositTimestamp;
         uint256 remainingTime = rewardsDistributionWindow - Math.min(timePassed, rewardsDistributionWindow);
 
-        return $.lastDepositAmount * remainingTime / rewardsDistributionWindow;
+        return Math.mulDiv(uint256($.lastDepositAmount), remainingTime, rewardsDistributionWindow, Math.Rounding.Ceil);
     }
 
     /**

diff --git a/mainnet-contracts/test/unit/PufferRevenueDepositorTest.t.sol b/mainnet-contracts/test/unit/PufferRevenueDepositorTest.t.sol
@@ -106,9 +106,16 @@ contract PufferRevenueDepositorTest is UnitTestHelper {
 
         assertEq(revenueDepositor.getPendingDistributionAmount(), 1, "Pending distribution amount should be 1");
 
-        // After half of the distribution window, the pending distribution amount is half of the total amount
+        // After half of the distribution window, the pending distribution amount should still be 1 due to rounding up
         vm.warp(block.timestamp + 12 hours);
+        assertEq(
+            revenueDepositor.getPendingDistributionAmount(),
+            1,
+            "Pending distribution amount should be 1 due to rounding up"
+        );
 
+        // Only after the full distribution window should it become 0
+        vm.warp(block.timestamp + 12 hours);
         assertEq(revenueDepositor.getPendingDistributionAmount(), 0, "Pending distribution amount should be 0");
     }
 
@@ -204,6 +211,15 @@ contract PufferRevenueDepositorTest is UnitTestHelper {
         revenueDepositor.callTargets(targets, data);
     }
 
+    function test_smallRewardsAmount_precisionLoss() public withRewardsDistributionWindow(1 days) {
+        vm.deal(address(revenueDepositor), 2); // 2 wei
+        vm.startPrank(OPERATIONS_MULTISIG);
+        revenueDepositor.depositRevenue();
+        assertEq(revenueDepositor.getPendingDistributionAmount(), 2, "Pending distribution amount should be 2");
+        vm.warp(block.timestamp + 1 seconds);
+        assertEq(revenueDepositor.getPendingDistributionAmount(), 2, "Pending distribution amount should be 2");
+    }
+
     function testRevert_constructor_zeroAddressVault() public {
         vm.expectRevert(IPufferRevenueDepositor.InvalidAddress.selector);
         new PufferRevenueDepositor(