On repay only approve minimum required amount

Author: lastperson

contracts/LiquidityPoolAave.sol

@@ -4,6 +4,7 @@ pragma solidity 0.8.28;
 import {IERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import {IERC20Metadata} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
 import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";
 import {IAavePoolAddressesProvider} from "./interfaces/IAavePoolAddressesProvider.sol";
 import {IAavePool, AaveDataTypes, NO_REFERRAL, INTEREST_RATE_MODE_VARIABLE} from "./interfaces/IAavePool.sol";
 import {IAaveOracle} from "./interfaces/IAaveOracle.sol";
@@ -214,7 +215,7 @@ contract LiquidityPoolAave is LiquidityPool {
         if (totalBorrowed == 0) return false;
         uint256 borrowTokenBalance = IERC20(borrowToken).balanceOf(address(this));
         if (borrowTokenBalance == 0) return false;
-        IERC20(borrowToken).forceApprove(address(AAVE_POOL), borrowTokenBalance);
+        IERC20(borrowToken).forceApprove(address(AAVE_POOL), Math.min(borrowTokenBalance, totalBorrowed));
         uint256 repaidAmount = AAVE_POOL.repay(
             borrowToken,
             borrowTokenBalance,

test/LiquidityPoolAave.ts

@@ -57,7 +57,7 @@ describe("LiquidityPoolAave", function () {
     // PRIME token used as not supported by aave
     const NON_SUPPORTED_TOKEN_ADDRESS = "0xb23d80f5FefcDDaa212212F028021B41DEd428CF";
     const NON_SUPPORTED_TOKEN_OWNER_ADDRESS = process.env.PRIME_OWNER_ADDRESS!;
-    if (!NON_SUPPORTED_TOKEN_OWNER_ADDRESS) 
+    if (!NON_SUPPORTED_TOKEN_OWNER_ADDRESS)
       throw new Error("Env variables not configured (PRIME_OWNER_ADDRESS missing)");
     const nonSupportedToken = await hre.ethers.getContractAt("ERC20", NON_SUPPORTED_TOKEN_ADDRESS);
     const nonSupportedTokenOwner = await hre.ethers.getImpersonatedSigner(NON_SUPPORTED_TOKEN_OWNER_ADDRESS);
@@ -72,7 +72,7 @@ describe("LiquidityPoolAave", function () {
     const defaultLtv = 5n * 10000n / 100n;
     const liquidityPool = (
       await deploy("LiquidityPoolAave", deployer, {},
-        usdc.target, AAVE_POOL_PROVIDER, admin.address, mpc_signer.address, healthFactor, defaultLtv 
+        usdc.target, AAVE_POOL_PROVIDER, admin.address, mpc_signer.address, healthFactor, defaultLtv
       )
     ) as LiquidityPoolAave;
 
@@ -182,10 +182,10 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature);  
+        signature);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
     });
-   
+
     it("Should calculate token ltv if decimals of token and collateral are different", async function () {
       const {
         liquidityPool, usdc, uni, mpc_signer, user, user2, usdcOwner, liquidityAdmin, USDC_DEC, UNI_DEC
@@ -254,7 +254,7 @@ describe("LiquidityPoolAave", function () {
         0n,
         2000000000n,
         signature))
-      .to.emit(mockTarget, "DataReceived").withArgs(additionalData);  
+      .to.emit(mockTarget, "DataReceived").withArgs(additionalData);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(0);
       expect(await rpl.balanceOf(mockTarget.target)).to.eq(amountToBorrow);
     });
@@ -288,7 +288,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature);  
+        signature);
       expect(await usdc.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
       expect(await aToken.balanceOf(liquidityPool.target)).to.be.greaterThanOrEqual(amountCollateral - 1n);
     });
@@ -339,8 +339,8 @@ describe("LiquidityPoolAave", function () {
       );
 
       await expect(mockBorrowSwap.connect(user).callBorrow(liquidityPool.target, borrowCalldata.data))
-        .to.emit(mockBorrowSwap, "Swapped").withArgs(swapData) 
-        .and.to.emit(mockTarget, "DataReceived").withArgs(additionalData);  
+        .to.emit(mockBorrowSwap, "Swapped").withArgs(swapData)
+        .and.to.emit(mockTarget, "DataReceived").withArgs(additionalData);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(0);
       expect(await rpl.balanceOf(mockBorrowSwap.target)).to.eq(amountToBorrow);
       expect(await uni.balanceOf(liquidityPool.target)).to.eq(0);
@@ -349,7 +349,8 @@ describe("LiquidityPoolAave", function () {
 
     it("Should repay a debt", async function () {
       const {
-        liquidityPool, usdc, uni, mpc_signer, user, user2, usdcOwner, uniOwner, liquidityAdmin, USDC_DEC, UNI_DEC
+        liquidityPool, usdc, uni, mpc_signer, user, user2, usdcOwner, uniOwner, liquidityAdmin, USDC_DEC, UNI_DEC,
+        aavePool,
       } = await loadFixture(deployAll);
       const amountCollateral = 1000n * USDC_DEC; // $1000
       await usdc.connect(usdcOwner).transfer(liquidityPool.target, amountCollateral);
@@ -376,13 +377,14 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature);  
+        signature);
       expect(await uni.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       await uni.connect(uniOwner).transfer(liquidityPool.target, amountToBorrow);
 
       await expect(liquidityPool.connect(user).repay([uni.target]))
-        .to.emit(liquidityPool, "Repaid");  
+        .to.emit(liquidityPool, "Repaid");
+      expect(await uni.allowance(liquidityPool.target, aavePool.target)).to.eq(0);
       expect(await uni.balanceOf(liquidityPool.target)).to.be.lessThan(amountToBorrow);
     });
 
@@ -416,7 +418,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature);  
+        signature);
       expect(await uni.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       await expect(liquidityPool.connect(pauser).pause())
@@ -425,7 +427,7 @@ describe("LiquidityPoolAave", function () {
       await uni.connect(uniOwner).transfer(liquidityPool.target, amountToBorrow);
 
       await expect(liquidityPool.connect(user).repay([uni.target]))
-        .to.emit(liquidityPool, "Repaid");  
+        .to.emit(liquidityPool, "Repaid");
       expect(await uni.balanceOf(liquidityPool.target)).to.be.lessThan(amountToBorrow);
     });
 
@@ -485,7 +487,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature1);  
+        signature1);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       const signature2 = await signBorrow(
@@ -507,7 +509,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         1n,
         2000000000n,
-        signature2);  
+        signature2);
       expect(await uni.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       // advance time by one hour
@@ -521,21 +523,21 @@ describe("LiquidityPoolAave", function () {
       // Repaying with the borrowed tokens that are still in the pool contract
       await expect(liquidityPool.connect(user).repay([uni.target, rpl.target]))
         .to.emit(liquidityPool, "Repaid").withArgs(uni.target, amountToBorrow)
-        .and.to.emit(liquidityPool, "Repaid").withArgs(rpl.target, amountToBorrow); 
+        .and.to.emit(liquidityPool, "Repaid").withArgs(rpl.target, amountToBorrow);
       const uniDebtAfter1 = await uniDebtToken.balanceOf(liquidityPool.target);
       expect(uniDebtAfter1).to.be.lessThan(uniDebtBefore);
       const rplDebtAfter1 = await rplDebtToken.balanceOf(liquidityPool.target);
       expect(rplDebtAfter1).to.be.lessThan(rplDebtBefore);
 
       await uni.connect(uniOwner).transfer(liquidityPool.target, amountToBorrow);
       await expect(liquidityPool.connect(user).repay([uni.target]))
-      .to.emit(liquidityPool, "Repaid");  
+      .to.emit(liquidityPool, "Repaid");
       const uniDebtAfter2 = await uniDebtToken.balanceOf(liquidityPool.target);
       expect(uniDebtAfter2).to.eq(0);
 
       await rpl.connect(rplOwner).transfer(liquidityPool.target, amountToBorrow);
       await expect(liquidityPool.connect(user).repay([rpl.target]))
-        .to.emit(liquidityPool, "Repaid");  
+        .to.emit(liquidityPool, "Repaid");
       const rplDebtAfter2 = await rplDebtToken.balanceOf(liquidityPool.target);
       expect(rplDebtAfter2).to.eq(0);
     });
@@ -570,7 +572,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature1);  
+        signature1);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       // advance time by one hour
@@ -583,7 +585,7 @@ describe("LiquidityPoolAave", function () {
       await rpl.connect(rplOwner).transfer(liquidityPool.target, amountToBorrow);
 
       await expect(liquidityPool.connect(user).repay([uni.target, rpl.target]))
-        .to.emit(liquidityPool, "Repaid");  
+        .to.emit(liquidityPool, "Repaid");
       const uniDebtAfter = await uniDebtToken.balanceOf(liquidityPool.target);
       expect(uniDebtAfter).to.eq(0);
       const rplDebtAfter = await rplDebtToken.balanceOf(liquidityPool.target);
@@ -620,7 +622,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature1);  
+        signature1);
       expect(await usdc.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
 
       // advance time by one hour
@@ -632,7 +634,7 @@ describe("LiquidityPoolAave", function () {
       await usdc.connect(usdcOwner).transfer(liquidityPool.target, amountToBorrow);
 
       await expect(liquidityPool.connect(user).repay([usdc.target]))
-        .to.emit(liquidityPool, "Repaid");  
+        .to.emit(liquidityPool, "Repaid");
       const usdcDebtAfter = await uniDebtToken.balanceOf(liquidityPool.target);
       expect(usdcDebtAfter).to.eq(0);
     });
@@ -960,7 +962,7 @@ describe("LiquidityPoolAave", function () {
 
     it("Should NOT borrow if borrowing is paused", async function () {
       const {liquidityPool, user, user2, withdrawProfit, mpc_signer, uni, UNI_DEC} = await loadFixture(deployAll);
-      
+
       // Pause borrowing
       await expect(liquidityPool.connect(withdrawProfit).pauseBorrow())
         .to.emit(liquidityPool, "BorrowPaused");
@@ -990,7 +992,7 @@ describe("LiquidityPoolAave", function () {
 
     it("Should NOT borrow if the contract is paused", async function () {
       const {liquidityPool, rpl, user, user2, pauser} = await loadFixture(deployAll);
-      
+
       // Pause the contract
       await expect(liquidityPool.connect(pauser).pause())
         .to.emit(liquidityPool, "Paused");
@@ -1173,7 +1175,7 @@ describe("LiquidityPoolAave", function () {
         0n,
         2000000000n,
         signature))
-      .to.emit(mockTarget, "DataReceived").withArgs(additionalData);  
+      .to.emit(mockTarget, "DataReceived").withArgs(additionalData);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(0);
       expect(await rpl.balanceOf(mockTarget.target)).to.eq(amountToBorrow);
 
@@ -1263,7 +1265,7 @@ describe("LiquidityPoolAave", function () {
       const {liquidityPool, user, liquidityAdmin, pauser} = await loadFixture(deployAll);
       await expect(liquidityPool.connect(pauser).pause())
         .to.emit(liquidityPool, "Paused");
-      
+
       await expect(liquidityPool.connect(liquidityAdmin).withdraw(user.address, 10))
         .to.be.revertedWithCustomError(liquidityPool, "EnforcedPause");
     });
@@ -1331,7 +1333,7 @@ describe("LiquidityPoolAave", function () {
         "0x",
         0n,
         2000000000n,
-        signature1);  
+        signature1);
       expect(await rpl.balanceOf(liquidityPool.target)).to.eq(amountToBorrow);
       expect(await rplDebtToken.balanceOf(liquidityPool.target)).to.be.greaterThan(0);
       await expect(liquidityPool.connect(withdrawProfit).withdrawProfit([rpl.target], user.address))