Universal deposit fee (#983)

* charge fee on all deposit

* unit tests compile

* test harness updates

* working on ERC20PoolQuoteTokenTest

* removed deposit fee cap

* more work on ERC20PoolQuoteTokenTest

* do not charge deposit fee if moving liquidity to higher price

src/PositionManager.sol

@@ -292,8 +292,7 @@ contract PositionManager is PermitERC721, IPositionManager, Multicall, Reentranc
         uint256 tokenId_,
         uint256 fromIndex_,
         uint256 toIndex_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external override nonReentrant mayInteract(pool_, tokenId_) {
         TokenInfo storage tokenInfo    = positionTokens[tokenId_];
         Position  storage fromPosition = tokenInfo.positions[fromIndex_];
@@ -336,8 +335,7 @@ contract PositionManager is PermitERC721, IPositionManager, Multicall, Reentranc
             vars.maxQuote,
             fromIndex_,
             toIndex_,
-            expiry_,
-            revertIfBelowLup_
+            expiry_
         );
 
         EnumerableSet.UintSet storage positionIndexes = tokenInfo.positionIndexes;

src/base/Pool.sol

@@ -151,8 +151,7 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
     function addQuoteToken(
         uint256 amount_,
         uint256 index_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external override nonReentrant returns (uint256 bucketLP_) {
         _revertAfterExpiry(expiry_);
 
@@ -170,8 +169,7 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
             poolState,
             AddQuoteParams({
                 amount:           amount_,
-                index:            index_,
-                revertIfBelowLup: revertIfBelowLup_
+                index:            index_
             })
         );
 
@@ -187,8 +185,7 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
         uint256 maxAmount_,
         uint256 fromIndex_,
         uint256 toIndex_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external override nonReentrant returns (uint256 fromBucketLP_, uint256 toBucketLP_, uint256 movedAmount_) {
         _revertAfterExpiry(expiry_);
 
@@ -203,7 +200,6 @@ abstract contract Pool is Clone, ReentrancyGuard, Multicall, IPool {
         moveParams.fromIndex        = fromIndex_;
         moveParams.toIndex          = toIndex_;
         moveParams.thresholdPrice   = Loans.getMax(loans).thresholdPrice;
-        moveParams.revertIfBelowLup = revertIfBelowLup_;
 
         uint256 newLup;
         (

src/interfaces/pool/commons/IPoolErrors.sol

@@ -185,7 +185,6 @@ interface IPoolErrors {
     error PoolUnderCollateralized();
 
     /**
-     *  @notice Actor is attempting to add or move quote tokens at a price below the `LUP`.
      *  @notice Actor is attempting to kick with bucket price below the `LUP`.
      */
     error PriceBelowLUP();

src/interfaces/pool/commons/IPoolInternals.sol

@@ -70,7 +70,6 @@ struct KickReserveAuctionParams {
 struct AddQuoteParams {
     uint256 amount;           // [WAD] amount to be added
     uint256 index;            // the index in which to deposit
-    bool    revertIfBelowLup; // revert tx if index in which to deposit is below LUP
 }
 
 /// @dev Struct used to hold parameters for `LenderAction.moveQuoteToken` action.
@@ -79,7 +78,6 @@ struct MoveQuoteParams {
     uint256 maxAmountToMove;  // [WAD] max amount to move between deposits
     uint256 toIndex;          // the deposit index where amount is moved to
     uint256 thresholdPrice;   // [WAD] max threshold price in pool
-    bool    revertIfBelowLup; // revert tx if quote token is moved from above the LUP to below the LUP
 }
 
 /// @dev Struct used to hold parameters for `LenderAction.removeQuoteToken` action.

src/interfaces/pool/commons/IPoolLenderActions.sol

@@ -16,14 +16,12 @@ interface IPoolLenderActions {
      *  @param  amount_           The amount of quote token to be added by a lender (`WAD` precision).
      *  @param  index_            The index of the bucket to which the quote tokens will be added.
      *  @param  expiry_           Timestamp after which this transaction will revert, preventing inclusion in a block with unfavorable price.
-     *  @param  revertIfBelowLup_ The tx will revert if price of the bucket to which the quote tokens will be added is below `LUP` price (and avoid paying fee for deposit below `LUP`).
      *  @return bucketLP_         The amount of `LP` changed for the added quote tokens (`WAD` precision).
      */
     function addQuoteToken(
         uint256 amount_,
         uint256 index_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external returns (uint256 bucketLP_);
 
     /**
@@ -32,7 +30,6 @@ interface IPoolLenderActions {
      *  @param  fromIndex_        The bucket index from which the quote tokens will be removed.
      *  @param  toIndex_          The bucket index to which the quote tokens will be added.
      *  @param  expiry_           Timestamp after which this transaction will revert, preventing inclusion in a block with unfavorable price.
-     *  @param  revertIfBelowLup_ The tx will revert if quote token is moved from above the `LUP` to below the `LUP` (and avoid paying fee for move below `LUP`).
      *  @return fromBucketLP_     The amount of `LP` moved out from bucket (`WAD` precision).
      *  @return toBucketLP_       The amount of `LP` moved to destination bucket (`WAD` precision).
      *  @return movedAmount_      The amount of quote token moved (`WAD` precision).
@@ -41,8 +38,7 @@ interface IPoolLenderActions {
         uint256 maxAmount_,
         uint256 fromIndex_,
         uint256 toIndex_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external returns (uint256 fromBucketLP_, uint256 toBucketLP_, uint256 movedAmount_);
 
     /**

src/interfaces/position/IPositionManagerOwnerActions.sol

@@ -55,15 +55,13 @@ interface IPositionManagerOwnerActions {
      *  @param  fromIndex_        The bucket index from which liquidity should be moved.
      *  @param  toIndex_          The bucket index to which liquidity should be moved.
      *  @param  expiry_           Timestamp after which this TX will revert, preventing inclusion in a block with unfavorable price.
-     *  @param  revertIfBelowLup_ The tx will revert if quote token is moved from above the `LUP` to below the `LUP` (and avoid paying fee for move below `LUP`).
      */
     function moveLiquidity(
         address pool_,
         uint256 tokenId_,
         uint256 fromIndex_,
         uint256 toIndex_,
-        uint256 expiry_,
-        bool    revertIfBelowLup_
+        uint256 expiry_
     ) external;
 
     /**

src/libraries/external/LenderActions.sol

@@ -89,7 +89,6 @@ library LenderActions {
     error InsufficientLiquidity();
     error InsufficientCollateral();
     error MoveToSameIndex();
-    error PriceBelowLUP();
 
     /***************************/
     /***  External Functions ***/
@@ -142,7 +141,6 @@ library LenderActions {
      *  @dev    same block when bucket becomes insolvent `BucketBankruptcyBlock()`
      *  @dev    no LP awarded in bucket `InsufficientLP()`
      *  @dev    calculated unscaled amount to add is 0 `InvalidAmount()`
-     *  @dev    deposit below `LUP` `PriceBelowLUP()`
      *  @dev    === Emit events ===
      *  @dev    - `AddQuoteToken`
      */
@@ -170,15 +168,8 @@ library LenderActions {
         uint256 bucketPrice           = _priceAt(params_.index);
         uint256 addedAmount           = params_.amount;
 
-        // charge unutilized deposit fee where appropriate
-        uint256 lupIndex = Deposits.findIndexOfSum(deposits_, poolState_.debt);
-        bool depositBelowLup = lupIndex != 0 && params_.index > lupIndex;
-
-        if (depositBelowLup) {
-            if (params_.revertIfBelowLup) revert PriceBelowLUP();
-
-            addedAmount = Maths.wmul(addedAmount, Maths.WAD - _depositFeeRate(poolState_.rate));
-        }
+        // charge deposit fee
+        addedAmount = Maths.wmul(addedAmount, Maths.WAD - _depositFeeRate(poolState_.rate));
 
         bucketLP_ = Buckets.quoteTokensToLP(
             bucket.collateral,
@@ -204,10 +195,8 @@ library LenderActions {
         // update bucket LP
         bucket.lps += bucketLP_;
 
-        // only need to recalculate LUP if the deposit was above it
-        if (!depositBelowLup) {
-            lupIndex = Deposits.findIndexOfSum(deposits_, poolState_.debt);
-        }
+        // calculate new LUP
+        uint256 lupIndex = Deposits.findIndexOfSum(deposits_, poolState_.debt);
         lup_ = _priceAt(lupIndex);
 
         emit AddQuoteToken(
@@ -234,7 +223,6 @@ library LenderActions {
      *  @dev    dust amount `DustAmountNotExceeded()`
      *  @dev    invalid index `InvalidIndex()`
      *  @dev    no LP awarded in to bucket `InsufficientLP()`
-     *  @dev    move below `LUP` `PriceBelowLUP()`
      *  @dev    === Emit events ===
      *  @dev    - `BucketBankruptcy`
      *  @dev    - `MoveQuoteToken`
@@ -285,11 +273,8 @@ library LenderActions {
             })
         );
 
-        lup_ = Deposits.getLup(deposits_, poolState_.debt);
-        // apply unutilized deposit fee if quote token is moved from above the LUP to below the LUP
-        if (vars.fromBucketPrice >= lup_ && vars.toBucketPrice < lup_) {
-            if (params_.revertIfBelowLup) revert PriceBelowLUP();
-
+        // apply deposit fee if moving to a lower-priced bucket
+        if (params_.fromIndex < params_.toIndex) {
             movedAmount_ = Maths.wmul(movedAmount_, Maths.WAD - _depositFeeRate(poolState_.rate));
         }
 
@@ -311,9 +296,8 @@ library LenderActions {
 
         Deposits.unscaledAdd(deposits_, params_.toIndex, Maths.wdiv(movedAmount_, vars.toBucketScale));
 
-        // recalculate LUP after adding amount in to bucket only if to bucket price is greater than LUP
-        if (vars.toBucketPrice > lup_) lup_ = Deposits.getLup(deposits_, poolState_.debt);
-
+        // recalculate LUP and HTP
+        lup_ = Deposits.getLup(deposits_, poolState_.debt);
         vars.htp = Maths.wmul(params_.thresholdPrice, poolState_.inflator);
 
         // check loan book's htp against new lup, revert if move drives LUP below HTP

src/libraries/helpers/PoolHelper.sol

@@ -126,13 +126,13 @@ import { Maths }   from '../internal/Maths.sol';
     /**
      * @notice Calculates the unutilized deposit fee, charged to lenders who deposit below the `LUP`.
      * @param  interestRate_ The current interest rate.
-     * @return Fee rate based upon the given interest rate, capped at 10%.
+     * @return Fee rate based upon the given interest rate
      */
     function _depositFeeRate(
         uint256 interestRate_
     ) pure returns (uint256) {
-        // current annualized rate divided by 365 (24 hours of interest), capped at 10%
-        return Maths.min(Maths.wdiv(interestRate_, 365 * 1e18), 0.1 * 1e18);
+        // current annualized rate divided by 365 * 3 (8 hours of interest)
+        return Maths.wdiv(interestRate_, 365 * 3e18);
     }
 
     /**

tests/brownie/test_invariants.py

@@ -327,7 +327,7 @@ class PoolStateMachine(BasePoolStateMachine):
 
         def setup(self):
             # add some initial liquidity in the pool
-            self.pool.addQuoteToken(MAX_LEND_AMOUNT, MAX_BUCKET, chain.time() + 30, False, {"from": lenders[0]})
+            self.pool.addQuoteToken(MAX_LEND_AMOUNT, MAX_BUCKET, chain.time() + 30, {"from": lenders[0]})
 
 
         ############## Lender rules ##############
@@ -343,7 +343,7 @@ def rule_add_quote_token(self, st_lend_amount, st_index, st_lender, st_sleep):
             success = True
 
             try:
-                self.pool.addQuoteToken(lend_amount, st_index, chain.time() + 30, False, {"from": lenders[st_lender]})
+                self.pool.addQuoteToken(lend_amount, st_index, chain.time() + 30, {"from": lenders[st_lender]})
                 chain.sleep(st_sleep)
             except:
                 success = False
@@ -363,7 +363,7 @@ def rule_swap_quote_for_collateral(self, st_lend_amount, st_bid_amount, st_index
                 if bucket_collateral < st_bid_amount:
                     self.pool.addCollateral(st_bid_amount, st_index, chain.time() + 30, {"from": bidders[st_bidder]})
 
-                self.pool.addQuoteToken(st_lend_amount, st_index, chain.time() + 30, False, {"from": lenders[st_lender]})
+                self.pool.addQuoteToken(st_lend_amount, st_index, chain.time() + 30, {"from": lenders[st_lender]})
                 self.pool.removeCollateral(st_bid_amount, st_index, {"from": lenders[st_lender]})
                 chain.sleep(st_sleep)
             except:
@@ -388,7 +388,7 @@ def rule_draw_debt(self, st_borrow_amount, st_lender, st_borrower, st_sleep):
 
                 pool_quote_on_deposit = self.pool_helper.pool.depositSize() - self.pool_helper.debt()
                 if pool_quote_on_deposit < st_borrow_amount:
-                    self.pool.addQuoteToken(st_borrow_amount + 100*1e18, MAX_BUCKET, chain.time() + 30, False, {"from": lenders[st_lender]})
+                    self.pool.addQuoteToken(st_borrow_amount + 100*1e18, MAX_BUCKET, chain.time() + 30, {"from": lenders[st_lender]})
 
                 pool_price = self.pool_helper.lup()
                 if pool_price == MAX_PRICE:  # if there is no LUP,
@@ -441,7 +441,7 @@ def rule_swap_collateral_for_quote(self, st_bid_amount, st_lend_amount, st_index
             try:
                 (_, _, _, bucket_deposit, _) = self.pool.bucketInfo(st_index)
                 if bucket_deposit < st_lend_amount:
-                    self.pool.addQuoteToken(st_lend_amount, st_index, chain.time() + 30, False, {"from": lenders[st_lender]})
+                    self.pool.addQuoteToken(st_lend_amount, st_index, chain.time() + 30, {"from": lenders[st_lender]})
 
                 self.pool.addCollateral(st_bid_amount, st_index, chain.time() + 30, {"from": bidders[st_bidder]})
                 self.pool.removeQuoteToken(st_lend_amount, st_index, {"from": bidders[st_bidder]})
@@ -491,8 +491,8 @@ class PoolStateMachine(BasePoolStateMachine):
 
         def setup(self):
             # add some initial liquidity in the pool
-            self.pool.addQuoteToken(MAX_BORROW_AMOUNT, MAX_BUCKET, chain.time() + 30, False, {"from": lenders[0]})
-            self.pool.addQuoteToken(MAX_BORROW_AMOUNT, MIN_BUCKET, chain.time() + 30, False, {"from": lenders[0]})
+            self.pool.addQuoteToken(MAX_BORROW_AMOUNT, MAX_BUCKET, chain.time() + 30, {"from": lenders[0]})
+            self.pool.addQuoteToken(MAX_BORROW_AMOUNT, MIN_BUCKET, chain.time() + 30, {"from": lenders[0]})
 
 
         ############## Borrower rules ##############
@@ -515,7 +515,7 @@ def rule_draw_debt(self, st_borrow_amount, st_lender, st_borrower, st_sleep):
 
                 pool_quote_on_deposit = self.pool_helper.pool.depositSize() - self.pool_helper.debt()
                 if pool_quote_on_deposit < st_borrow_amount:
-                    self.pool.addQuoteToken(st_borrow_amount + 100*1e18, MAX_BUCKET, chain.time() + 30, False, {"from": lenders[st_lender]})
+                    self.pool.addQuoteToken(st_borrow_amount + 100*1e18, MAX_BUCKET, chain.time() + 30, {"from": lenders[st_lender]})
 
                 pool_price = self.pool_helper.lup()
                 if pool_price == MAX_PRICE:  # if there is no LUP,

tests/brownie/test_scaled_pool.py

@@ -14,7 +14,7 @@ def test_quote_deposit_move_remove_scaled(
     with test_utils.GasWatcher(["addQuoteToken", "moveQuoteToken", "removeQuoteToken"]):
         add_txes = []
         for i in range(2530, 2550):
-            tx = scaled_pool.addQuoteToken(100 * 10**18, i, chain.time() + 30, False, {"from": lenders[0]})
+            tx = scaled_pool.addQuoteToken(100 * 10**18, i, chain.time() + 30, {"from": lenders[0]})
             add_txes.append(tx)
         with capsys.disabled():
             print("\n==================================")
@@ -25,7 +25,7 @@ def test_quote_deposit_move_remove_scaled(
 
         move_txes = []
         for i in range(2530, 2550):
-            tx = scaled_pool.moveQuoteToken(100 * 10**18, i, i + 30, chain.time() + 30, False, {"from": lenders[0]})
+            tx = scaled_pool.moveQuoteToken(100 * 10**18, i, i + 30, chain.time() + 30, {"from": lenders[0]})
             move_txes.append(tx)
         with capsys.disabled():
             print("\n==================================")
@@ -57,9 +57,9 @@ def test_borrow_repay_scaled(
     with test_utils.GasWatcher(["addQuoteToken", "drawDebt", "repayDebt"]):
 
         expiry = chain.time() + 30
-        scaled_pool.addQuoteToken(100 * 10**18, 2550, expiry, False, {"from": lenders[0]})
-        scaled_pool.addQuoteToken(100 * 10**18, 2560, expiry, False, {"from": lenders[0]})
-        scaled_pool.addQuoteToken(100 * 10**18, 2570, expiry, False, {"from": lenders[0]})
+        scaled_pool.addQuoteToken(100 * 10**18, 2550, expiry, {"from": lenders[0]})
+        scaled_pool.addQuoteToken(100 * 10**18, 2560, expiry, {"from": lenders[0]})
+        scaled_pool.addQuoteToken(100 * 10**18, 2570, expiry, {"from": lenders[0]})
 
         col_txes = []
         for i in range(10):

tests/brownie/test_stable_volatile.py

@@ -96,7 +96,7 @@ def add_initial_liquidity(lenders, pool_helper, chain):
             price_index = price_position + MAX_BUCKET
             log(f" lender {i} depositing {deposit_amount/1e18} into bucket {price_index} "
                 f"({pool_helper.indexToPrice(price_index) / 1e18:.1f})")
-            pool_helper.pool.addQuoteToken(deposit_amount, price_index, chain.time() + 30, False, {"from": lenders[i]})
+            pool_helper.pool.addQuoteToken(deposit_amount, price_index, chain.time() + 30, {"from": lenders[i]})
 
 
 def draw_initial_debt(borrowers, pool_helper, test_utils, chain, target_utilization):
@@ -294,7 +294,7 @@ def add_quote_token(lender, lender_index, pool_helper, chain):
         return None
 
     log(f" lender   {lender_index:>4} adding {quantity / 10**18:.1f} liquidity at {deposit_price / 10**18:.1f}")
-    tx = pool_helper.pool.addQuoteToken(quantity, deposit_index, chain.time() + 15, False, {"from": lender})
+    tx = pool_helper.pool.addQuoteToken(quantity, deposit_index, chain.time() + 15, {"from": lender})
     return deposit_price
 
 

tests/forge/interactions/ERC20TakeWithExternalLiquidity.t.sol

@@ -54,11 +54,11 @@ contract ERC20TakeWithExternalLiquidityTest is Test {
         // add liquidity to the Ajna pool
         vm.startPrank(_lender);
         usdc.approve(address(_ajnaPool), type(uint256).max);
-        _ajnaPool.addQuoteToken(2_000 * 1e18, 3696, type(uint256).max, false);
-        _ajnaPool.addQuoteToken(5_000 * 1e18, 3698, type(uint256).max, false);
-        _ajnaPool.addQuoteToken(11_000 * 1e18, 3700, type(uint256).max, false);
-        _ajnaPool.addQuoteToken(25_000 * 1e18, 3702, type(uint256).max, false);
-        _ajnaPool.addQuoteToken(30_000 * 1e18, 3704, type(uint256).max, false);
+        _ajnaPool.addQuoteToken(2_000 * 1e18, 3696, type(uint256).max);
+        _ajnaPool.addQuoteToken(5_000 * 1e18, 3698, type(uint256).max);
+        _ajnaPool.addQuoteToken(11_000 * 1e18, 3700, type(uint256).max);
+        _ajnaPool.addQuoteToken(25_000 * 1e18, 3702, type(uint256).max);
+        _ajnaPool.addQuoteToken(30_000 * 1e18, 3704, type(uint256).max);
         vm.stopPrank();
 
         // borrower draws debt

tests/forge/interactions/PurchaseQuoteWithExternalLiquidity.t.sol

@@ -28,7 +28,7 @@ contract PurchaseQuoteWithExternalLiquidityTest is Test {
         deal(USDC, _lender, 120_000 * 1e6);
         vm.startPrank(_lender);
         usdc.approve(address(_ajnaPool), type(uint256).max);
-        _ajnaPool.addQuoteToken(5_000 * 1e18, 500, type(uint256).max, false);
+        _ajnaPool.addQuoteToken(5_000 * 1e18, 500, type(uint256).max);
         vm.stopPrank();
     }