From 5e73564e4f9c86a50e319070fdcbec77d0d44935 Mon Sep 17 00:00:00 2001
From: Josh Levine <joshuapark95@gmail.com>
Date: Thu, 11 Nov 2021 21:13:57 -0600
Subject: [PATCH] fix(Periphery): make a pass on swap rounding bug

---
 pkg/core/src/Periphery.sol                    |  2 +-
 pkg/core/src/adapters/BaseAdapter.sol         |  2 +-
 pkg/deployments/deploy/simulated/02-series.js | 26 +++++++++++++++++--
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/pkg/core/src/Periphery.sol b/pkg/core/src/Periphery.sol
index 47859827d..5bc632d0f 100644
--- a/pkg/core/src/Periphery.sol
+++ b/pkg/core/src/Periphery.sol
@@ -348,7 +348,7 @@ contract Periphery is Trust {
 
             // (5) Combine zeros and claim
             uint256 tBal = divider.combine(adapter, maturity, zBal);
-            return (keccak256("ERC3156FlashBorrower.onFlashLoan"), tBal - amount);
+            return (keccak256("ERC3156FlashBorrower.onFlashLoan"), amount - tBal);
         }
         return (keccak256("ERC3156FlashBorrower.onFlashLoan"), 0);
     }
diff --git a/pkg/core/src/adapters/BaseAdapter.sol b/pkg/core/src/adapters/BaseAdapter.sol
index 6e275d548..87bc0ecd1 100644
--- a/pkg/core/src/adapters/BaseAdapter.sol
+++ b/pkg/core/src/adapters/BaseAdapter.sol
@@ -87,7 +87,7 @@ abstract contract BaseAdapter is Initializable {
         require(target.transfer(address(receiver), amount), Errors.FlashTransferFailed);
         (bytes32 keccak, uint256 value) = IPeriphery(receiver).onFlashLoan(data, msg.sender, adapter, maturity, amount);
         require(keccak == CALLBACK_SUCCESS, Errors.FlashCallbackFailed);
-        require(target.transferFrom(address(receiver), address(this), amount), Errors.FlashRepayFailed);
+        require(target.transferFrom(address(receiver), address(this), amount - 1), Errors.FlashRepayFailed);
         return (true, value);
     }
 
diff --git a/pkg/deployments/deploy/simulated/02-series.js b/pkg/deployments/deploy/simulated/02-series.js
index 7195d8c7b..ce223c135 100644
--- a/pkg/deployments/deploy/simulated/02-series.js
+++ b/pkg/deployments/deploy/simulated/02-series.js
@@ -24,7 +24,10 @@ module.exports = async function ({ ethers, getNamedAccounts }) {
       const mockAdapterImpl = await ethers.getContract("MockAdapter");
       const adapter = new ethers.Contract(adapterAddress, mockAdapterImpl.interface, signer);
 
-      const { zero: zeroAddress } = await periphery.callStatic.sponsorSeries(adapter.address, seriesMaturity);
+      const { zero: zeroAddress, claim: claimAddress } = await periphery.callStatic.sponsorSeries(
+        adapter.address,
+        seriesMaturity,
+      );
       console.log(`Initializing Series maturing on ${dayjs(seriesMaturity * 1000)} for ${targetName}`);
       await periphery.sponsorSeries(adapter.address, seriesMaturity).then(tx => tx.wait());
 
@@ -33,6 +36,7 @@ module.exports = async function ({ ethers, getNamedAccounts }) {
 
       const { abi: tokenAbi } = await deployments.getArtifact("Token");
       const zero = new ethers.Contract(zeroAddress, tokenAbi, signer);
+      const claim = new ethers.Contract(claimAddress, tokenAbi, signer);
 
       const zeroBalance = await zero.balanceOf(deployer);
 
@@ -44,12 +48,30 @@ module.exports = async function ({ ethers, getNamedAccounts }) {
       console.log("Minting Underyling for the Balancer Vault");
       await underlying.mint(mockBalancerVault.address, zeroBalance).then(tx => tx.wait());
 
-      console.log(`Sanity check swap`);
+      console.log(`--- Sanity check swap ---`);
       await target.approve(periphery.address, ethers.constants.MaxUint256).then(tx => tx.wait());
 
+      console.log("swapping target for zeros");
       await periphery
         .swapTargetForZeros(adapter.address, seriesMaturity, ethers.utils.parseEther("1"), 0)
         .then(tx => tx.wait());
+
+      console.log("swapping target for claims");
+      await periphery
+        .swapTargetForClaims(adapter.address, seriesMaturity, ethers.utils.parseEther("1"))
+        .then(tx => tx.wait());
+
+      console.log("swapping zeros for target");
+      await zero.approve(periphery.address, ethers.constants.MaxUint256).then(tx => tx.wait());
+      await periphery
+        .swapZerosForTarget(adapter.address, seriesMaturity, ethers.utils.parseEther("0.5"), 0)
+        .then(tx => tx.wait());
+
+      console.log("swapping claims for target");
+      await claim.approve(periphery.address, ethers.constants.MaxUint256).then(tx => tx.wait());
+      await periphery
+        .swapClaimsForTarget(adapter.address, seriesMaturity, ethers.utils.parseEther("0.5"))
+        .then(tx => tx.wait());
     }
   }
 };