[WIP] Adding onBehalfOf to flashloan

contracts/interfaces/ILendingPool.sol

@@ -274,6 +274,7 @@ interface ILendingPool {
     address reserve,
     uint256 amount,
     uint256 debtType,
+    address onBehalfOf,
     bytes calldata params,
     uint16 referralCode
   ) external;

contracts/lendingpool/LendingPool.sol

@@ -498,6 +498,7 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage
    * @param asset The address of the principal reserve
    * @param amount The amount requested for this flashloan
    * @param mode Type of the debt to open if the flash loan is not returned. 0 -> Don't open any debt, just revert, 1 -> stable, 2 -> variable
+   * @param onBehalfOf If mode is not 0, then the address to take the debt onBehalfOf. The address must already have approved `msg.sender` to incur the debt on their behalf.
    * @param params Variadic packed params to pass to the receiver as extra information
    * @param referralCode Referral code of the flash loan
    **/
@@ -506,6 +507,7 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage
     address asset,
     uint256 amount,
     uint256 mode,
+    address onBehalfOf,
     bytes calldata params,
     uint16 referralCode
   ) external override {
@@ -549,7 +551,7 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage
         ExecuteBorrowParams(
           asset,
           msg.sender,
-          msg.sender,
+          onBehalfOf,
           vars.amountPlusPremium,
           mode,
           vars.aTokenAddress,

test/flashloan.spec.ts

@@ -51,6 +51,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
       weth.address,
       ethers.utils.parseEther('0.8'),
       0,
+      _mockFlashLoanReceiver.address,
       '0x10',
       '0'
     );
@@ -80,6 +81,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
       weth.address,
       '1000720000000000000',
       0,
+      _mockFlashLoanReceiver.address,
       '0x10',
       '0'
     );
@@ -111,6 +113,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
           weth.address,
           ethers.utils.parseEther('0.8'),
           0,
+          _mockFlashLoanReceiver.address,
           '0x10',
           '0'
         )
@@ -131,6 +134,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
           weth.address,
           ethers.utils.parseEther('0.8'),
           0,
+          _mockFlashLoanReceiver.address,
           '0x10',
           '0'
         )
@@ -151,6 +155,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
           weth.address,
           ethers.utils.parseEther('0.8'),
           4,
+          _mockFlashLoanReceiver.address,
           '0x10',
           '0'
         )
@@ -179,6 +184,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
         weth.address,
         ethers.utils.parseEther('0.8'),
         2,
+        caller.address,
         '0x10',
         '0'
       );
@@ -197,14 +203,16 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
   });
 
   it('tries to take a very small flashloan, which would result in 0 fees (revert expected)', async () => {
-    const {pool, weth} = testEnv;
+    const {pool, weth, users} = testEnv;
+    const caller = users[1];
 
     await expect(
-      pool.flashLoan(
+      pool.connect(caller.signer).flashLoan(
         _mockFlashLoanReceiver.address,
         weth.address,
         '1', //1 wei loan
         2,
+        caller.address,
         '0x10',
         '0'
       )
@@ -212,14 +220,16 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
   });
 
   it('tries to take a flashloan that is bigger than the available liquidity (revert expected)', async () => {
-    const {pool, weth} = testEnv;
+    const {pool, weth, users} = testEnv;
+    const caller = users[1];
 
     await expect(
-      pool.flashLoan(
+      pool.connect(caller.signer).flashLoan(
         _mockFlashLoanReceiver.address,
         weth.address,
         '1004415000000000000', //slightly higher than the available liquidity
         2,
+        caller.address,
         '0x10',
         '0'
       ),
@@ -228,10 +238,21 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
   });
 
   it('tries to take a flashloan using a non contract address as receiver (revert expected)', async () => {
-    const {pool, deployer, weth} = testEnv;
+    const {pool, deployer, weth, users} = testEnv;
+    const caller = users[1];
 
     await expect(
-      pool.flashLoan(deployer.address, weth.address, '1000000000000000000', 2, '0x10', '0')
+      pool
+        .connect(caller.signer)
+        .flashLoan(
+          deployer.address,
+          weth.address,
+          '1000000000000000000',
+          2,
+          caller.address,
+          '0x10',
+          '0'
+        )
     ).to.be.reverted;
   });
 
@@ -260,6 +281,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
       usdc.address,
       flashloanAmount,
       0,
+      _mockFlashLoanReceiver.address,
       '0x10',
       '0'
     );
@@ -297,7 +319,15 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
     await expect(
       pool
         .connect(caller.signer)
-        .flashLoan(_mockFlashLoanReceiver.address, usdc.address, flashloanAmount, 2, '0x10', '0')
+        .flashLoan(
+          _mockFlashLoanReceiver.address,
+          usdc.address,
+          flashloanAmount,
+          0,
+          _mockFlashLoanReceiver.address,
+          '0x10',
+          '0'
+        )
     ).to.be.revertedWith(COLLATERAL_BALANCE_IS_0);
   });
 
@@ -320,7 +350,15 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
 
     await pool
       .connect(caller.signer)
-      .flashLoan(_mockFlashLoanReceiver.address, usdc.address, flashloanAmount, 2, '0x10', '0');
+      .flashLoan(
+        _mockFlashLoanReceiver.address,
+        usdc.address,
+        flashloanAmount,
+        2,
+        caller.signer,
+        '0x10',
+        '0'
+      );
     const {variableDebtTokenAddress} = await helpersContract.getReserveTokensAddresses(
       usdc.address
     );
@@ -355,7 +393,15 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
     await expect(
       pool
         .connect(caller.signer)
-        .flashLoan(_mockFlashLoanReceiver.address, weth.address, flashAmount, 0, '0x10', '0')
+        .flashLoan(
+          _mockFlashLoanReceiver.address,
+          weth.address,
+          flashAmount,
+          0,
+          _mockFlashLoanReceiver.address,
+          '0x10',
+          '0'
+        )
     ).to.be.revertedWith(SAFEERC20_LOWLEVEL_CALL);
   });
 
@@ -370,7 +416,15 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
 
     await pool
       .connect(caller.signer)
-      .flashLoan(_mockFlashLoanReceiver.address, weth.address, flashAmount, 1, '0x10', '0');
+      .flashLoan(
+        _mockFlashLoanReceiver.address,
+        weth.address,
+        flashAmount,
+        1,
+        caller.signer,
+        '0x10',
+        '0'
+      );
 
     const {stableDebtTokenAddress} = await helpersContract.getReserveTokensAddresses(weth.address);