Revert on zero amounts

docs/Functions.md

@@ -66,7 +66,7 @@
 	reverts on:
 	- deposits locked RemoveDepositLockedByAuctionDebt()
 	- LenderActions.moveQuoteToken():
-		- same index MoveToSamePrice()
+		- same index MoveToSameIndex()
 		- dust amount DustAmountNotExceeded()
 		- invalid index InvalidIndex()
 

src/base/Pool.sol

@@ -326,6 +326,12 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
         );
     }
 
+    /// @inheritdoc IPoolLenderActions
+    function updateInterest() external override nonReentrant {
+        PoolState memory poolState = _accruePoolInterest();
+        _updateInterestState(poolState, _lup(poolState.debt));
+    }
+
     /*****************************/
     /*** Liquidation Functions ***/
     /*****************************/

src/interfaces/pool/commons/IPoolErrors.sol

@@ -107,11 +107,21 @@ interface IPoolErrors {
      */
     error InsufficientLiquidity();
 
+    /**
+     *  @notice When settling pool debt the number of buckets to use should be greater than 0.
+     */
+    error InvalidBucketDepth();
+
     /**
      *  @notice When transferring LPs between indices, the new index must be a valid index.
      */
     error InvalidIndex();
 
+    /**
+     *  @notice The amount used for performed action should be greater than 0.
+     */
+    error InvalidAmount();
+
     /**
      *  @notice Borrower is attempting to borrow more quote token than is available before the supplied limitIndex.
      */
@@ -129,9 +139,9 @@ interface IPoolErrors {
     error LUPGreaterThanTP();
 
     /**
-     *  @notice FromIndex_ and toIndex_ arguments to move are the same.
+     *  @notice From index and to index arguments to move are the same.
      */
-    error MoveToSamePrice();
+    error MoveToSameIndex();
 
     /**
      *  @notice Owner of the LPs must have approved the new owner prior to transfer.

src/interfaces/pool/commons/IPoolLenderActions.sol

@@ -103,4 +103,9 @@ interface IPoolLenderActions {
         address newOwner,
         uint256[] calldata indexes
     ) external;
+
+    /**
+     *  @notice Called by lenders to update pool interest rate (can be updated only once in a 12 hours period of time).
+     */
+    function updateInterest() external;
 }

src/libraries/external/Auctions.sol

@@ -162,6 +162,8 @@ library Auctions {
     error CollateralRoundingNeededButNotPossible();
     error InsufficientLiquidity();
     error InsufficientCollateral();
+    error InvalidBucketDepth();
+    error InvalidAmount();
     error NoAuction();
     error NoReserves();
     error NoReservesAuction();
@@ -205,6 +207,9 @@ library Auctions {
         uint256 collateralSettled_,
         uint256 t0DebtSettled_
     ) {
+        // revert if no bucket to settle
+        if (params_.bucketDepth == 0 ) revert InvalidBucketDepth();
+
         uint256 kickTime = auctions_.liquidations[params_.borrower].kickTime;
         if (kickTime == 0) revert NoAuction();
 
@@ -559,10 +564,12 @@ library Auctions {
         uint256 collateral_,
         uint256 collateralScale_
     ) external returns (TakeResult memory result_) {
+        // revert if no amount to take
+        if (collateral_ == 0) revert InvalidAmount();
+
         Borrower memory borrower = loans_.borrowers[borrowerAddress_];
 
         if (
-            (collateral_         == 0)                                                    || // revert if amount to take is 0
             (poolState_.poolType == uint8(PoolType.ERC721) && borrower.collateral < 1e18) || // revert in case of NFT take when there isn't a full token to be taken
             (poolState_.poolType == uint8(PoolType.ERC20)  && borrower.collateral == 0)      // revert in case of ERC20 take when no collateral to be taken
         ) {
@@ -693,6 +700,9 @@ library Auctions {
         ReserveAuctionState storage reserveAuction_,
         uint256 maxAmount_
     ) external returns (uint256 amount_, uint256 ajnaRequired_) {
+        // revert if no amount to be taken
+        if (maxAmount_ == 0) revert InvalidAmount();
+
         uint256 kicked = reserveAuction_.kicked;
 
         if (kicked != 0 && block.timestamp - kicked <= 72 hours) {

src/libraries/external/BorrowerActions.sol

@@ -73,6 +73,7 @@ library BorrowerActions {
     error BorrowerNotSender();
     error BorrowerUnderCollateralized();
     error InsufficientCollateral();
+    error InvalidAmount();
     error LimitIndexExceeded();
     error NoDebt();
 
@@ -117,12 +118,15 @@ library BorrowerActions {
     ) external returns (
         DrawDebtResult memory result_
     ) {
-        Borrower memory borrower = loans_.borrowers[borrowerAddress_];
-
         DrawDebtLocalVars memory vars;
+        vars.pledge = collateralToPledge_ != 0;
+        vars.borrow = amountToBorrow_ != 0;
+
+        // revert if no amount to pledge or borrow
+        if (!vars.pledge && !vars.borrow) revert InvalidAmount();
+
+        Borrower memory borrower = loans_.borrowers[borrowerAddress_];
 
-        vars.pledge       = collateralToPledge_ != 0;
-        vars.borrow       = amountToBorrow_ != 0 || limitIndex_ != 0; // enable an intentional 0 borrow loan call to update borrower's loan state
         vars.borrowerDebt = Maths.wmul(borrower.t0Debt, poolState_.inflator);
         vars.inAuction    = _inAuction(auctions_, borrowerAddress_);
 
@@ -219,11 +223,6 @@ library BorrowerActions {
             vars.stampT0Np = true;
         }
 
-        // calculate LUP if it wasn't calculated previously
-        if (!vars.pledge && !vars.borrow) {
-            result_.newLup = _lup(deposits_, result_.poolDebt);
-        }
-
         // update loan state
         Loans.update(
             loans_,
@@ -277,12 +276,15 @@ library BorrowerActions {
     ) external returns (
         RepayDebtResult memory result_
     ) {
-        Borrower memory borrower = loans_.borrowers[borrowerAddress_];
-
         RepayDebtLocalVars memory vars;
+        vars.repay = maxQuoteTokenAmountToRepay_ != 0;
+        vars.pull  = collateralAmountToPull_     != 0;
+
+        // revert if no amount to pledge or borrow
+        if (!vars.repay && !vars.pull) revert InvalidAmount();
+
+        Borrower memory borrower = loans_.borrowers[borrowerAddress_];
 
-        vars.repay        = maxQuoteTokenAmountToRepay_ != 0;
-        vars.pull         = collateralAmountToPull_     != 0;
         vars.borrowerDebt = Maths.wmul(borrower.t0Debt, poolState_.inflator);
         vars.inAuction    = _inAuction(auctions_, borrowerAddress_);
 
@@ -379,11 +381,6 @@ library BorrowerActions {
             result_.poolCollateral -= collateralAmountToPull_;
         }
 
-        // calculate LUP if it wasn't calculated previously
-        if (!vars.repay && !vars.pull) {
-            result_.newLup = _lup(deposits_, result_.poolDebt);
-        }
-
         // update loan state
         Loans.update(
             loans_,

src/libraries/external/LenderActions.sol

@@ -81,12 +81,13 @@ library LenderActions {
     error DustAmountNotExceeded();
     error NoAllowance();
     error InvalidIndex();
+    error InvalidAmount();
     error LUPBelowHTP();
     error NoClaim();
     error InsufficientLPs();
     error InsufficientLiquidity();
     error InsufficientCollateral();
-    error MoveToSamePrice();
+    error MoveToSameIndex();
     error TransferorNotApproved();
     error TransferToSameOwner();
 
@@ -110,6 +111,9 @@ library LenderActions {
         uint256 collateralAmountToAdd_,
         uint256 index_
     ) external returns (uint256 bucketLPs_) {
+        // revert if no amount to be added
+        if (collateralAmountToAdd_ == 0) revert InvalidAmount();
+        // revert if adding at invalid index
         if (index_ == 0 || index_ > MAX_FENWICK_INDEX) revert InvalidIndex();
 
         uint256 bucketDeposit = Deposits.valueAt(deposits_, index_);
@@ -143,6 +147,9 @@ library LenderActions {
         PoolState calldata poolState_,
         AddQuoteParams calldata params_
     ) external returns (uint256 bucketLPs_, uint256 lup_) {
+        // revert if no amount to be added
+        if (params_.amount == 0) revert InvalidAmount();
+        // revert if adding to an invalid index
         if (params_.index == 0 || params_.index > MAX_FENWICK_INDEX) revert InvalidIndex();
 
         Bucket storage bucket = buckets_[params_.index];
@@ -196,7 +203,7 @@ library LenderActions {
      *              - decrement bucket.lps accumulator for from bucket
      *              - increment bucket.lps accumulator for to bucket
      *  @dev    reverts on:
-     *              - same index MoveToSamePrice()
+     *              - same index MoveToSameIndex()
      *              - dust amount DustAmountNotExceeded()
      *              - invalid index InvalidIndex()
      *  @dev    emit events:
@@ -209,8 +216,10 @@ library LenderActions {
         PoolState calldata poolState_,
         MoveQuoteParams calldata params_
     ) external returns (uint256 fromBucketRedeemedLPs_, uint256 toBucketLPs_, uint256 movedAmount_, uint256 lup_) {
+        if (params_.maxAmountToMove == 0)
+            revert InvalidAmount();
         if (params_.fromIndex == params_.toIndex)
-            revert MoveToSamePrice();
+            revert MoveToSameIndex();
         if (params_.maxAmountToMove != 0 && params_.maxAmountToMove < poolState_.quoteDustLimit)
             revert DustAmountNotExceeded();
         if (params_.toIndex == 0 || params_.toIndex > MAX_FENWICK_INDEX) 
@@ -344,6 +353,9 @@ library LenderActions {
         PoolState calldata poolState_,
         RemoveQuoteParams calldata params_
     ) external returns (uint256 removedAmount_, uint256 redeemedLPs_, uint256 lup_) {
+        // revert if no amount to be removed
+        if (params_.maxAmount == 0) revert InvalidAmount();
+
         Bucket storage bucket = buckets_[params_.index];
         Lender storage lender = bucket.lenders[msg.sender];
 
@@ -415,6 +427,9 @@ library LenderActions {
         uint256 amount_,
         uint256 index_
     ) external returns (uint256 lpAmount_) {
+        // revert if no amount to be removed
+        if (amount_ == 0) revert InvalidAmount();
+
         Bucket storage bucket = buckets_[index_];
 
         uint256 bucketCollateral = bucket.collateral;
@@ -480,6 +495,9 @@ library LenderActions {
         uint256 maxAmount_,
         uint256 index_
     ) external returns (uint256, uint256) {
+        // revert if no amount to remove
+        if (maxAmount_ == 0) revert InvalidAmount();
+
         return _removeMaxCollateral(
             buckets_,
             deposits_,

tests/forge/ERC20Pool/ERC20DSTestPlus.sol

@@ -54,8 +54,10 @@ abstract contract ERC20DSTestPlus is DSTestPlus, IERC20PoolEvents {
         // mint quote tokens to borrower address equivalent to the current debt
         deal(_pool.quoteTokenAddress(), borrower, currentDebt);
 
-        // repay current debt and pull all collateral
-        _repayDebtNoLupCheck(borrower, borrower, tokenDebt, currentDebt, borrowerCollateral);
+        // repay current debt and pull all collateral if any
+        if (tokenDebt != 0 || borrowerCollateral != 0) {
+            _repayDebtNoLupCheck(borrower, borrower, tokenDebt, currentDebt, borrowerCollateral);
+        }
 
         // check borrower state after repay of loan and pull collateral
         (borrowerT0debt, borrowerCollateral, ) = _pool.borrowerInfo(borrower);
@@ -237,22 +239,6 @@ abstract contract ERC20DSTestPlus is DSTestPlus, IERC20PoolEvents {
         borrowers.add(from);
     }
 
-    function _borrowZeroAmount(
-        address from,
-        uint256 amount,
-        uint256 indexLimit,
-        uint256 newLup
-    ) internal {
-        changePrank(from);
-        vm.expectEmit(true, true, false, true);
-        emit DrawDebt(from, amount, 0, newLup);
-
-        ERC20Pool(address(_pool)).drawDebt(from, amount, indexLimit, 0);
-
-        // Add for tearDown
-        borrowers.add(from);
-    }
-
     function _drawDebt(
         address from,
         address borrower,

tests/forge/ERC20Pool/ERC20PoolBorrow.t.sol

@@ -432,12 +432,7 @@ contract ERC20PoolBorrowTest is ERC20HelperContract {
 
         skip(10 days);
 
-        _borrowZeroAmount({
-            from:       _borrower,
-            amount:     0,
-            indexLimit: 3_000,
-            newLup:     2_981.007422784467321543 * 1e18
-        });
+        _updateInterest();
 
         expectedDebt = 21_157.152643010853304038 * 1e18;
 
@@ -462,15 +457,14 @@ contract ERC20PoolBorrowTest is ERC20HelperContract {
             borrower:                  _borrower,
             borrowerDebt:              expectedDebt,
             borrowerCollateral:        50 * 1e18,
-            borrowert0Np:              448.381722115384615591 * 1e18,
+            borrowert0Np:              445.838278846153846359 * 1e18,
             borrowerCollateralization: 7.044916376706357984 * 1e18
         });
         _assertLenderInterest(liquidityAdded, 119.836959946754650000 * 1e18);
 
         skip(10 days);
 
-        // call drawDebt to restamp the loan's neutral price
-        IERC20Pool(address(_pool)).drawDebt(_borrower, 0, 0, 0);
+        _updateInterest();
 
         expectedDebt = 21_199.628356897284442294 * 1e18;
 
@@ -495,7 +489,7 @@ contract ERC20PoolBorrowTest is ERC20HelperContract {
             borrower:                  _borrower,
             borrowerDebt:              expectedDebt,
             borrowerCollateral:        50 * 1e18,
-            borrowert0Np:              448.381722115384615591 * 1e18,
+            borrowert0Np:              445.838278846153846359 * 1e18,
             borrowerCollateralization: 7.030801136225104190 * 1e18
         });
         _assertLenderInterest(liquidityAdded, 157.005764521268350000 * 1e18);
@@ -526,7 +520,7 @@ contract ERC20PoolBorrowTest is ERC20HelperContract {
             borrower:                  _borrower,
             borrowerDebt:              expectedDebt,
             borrowerCollateral:        50 * 1e18,
-            borrowert0Np:              448.381722115384615591 * 1e18,
+            borrowert0Np:              445.838278846153846359 * 1e18,
             borrowerCollateralization: 7.015307034516347067 * 1e18
         });
     }