Audit nice to have changes

spot-contracts/contracts/PerpetualTranche.sol

@@ -678,6 +678,16 @@ contract PerpetualTranche is
     }
 
     /// @inheritdoc IPerpetualTranche
+    function getReserveTokenBalance(IERC20Upgradeable token) external override afterStateUpdate returns (uint256) {
+        if (!_inReserve(token)) {
+            return 0;
+        }
+        return _reserveBalance(token);
+    }
+
+    /// @inheritdoc IPerpetualTranche
+    /// @dev In the case of the collateral token, it returns the "virtual" tranche balance.
+    //       In all other cases, it just returns the token balance.
     function getReserveTrancheBalance(IERC20Upgradeable tranche) external override afterStateUpdate returns (uint256) {
         if (!_inReserve(tranche)) {
             return 0;

spot-contracts/contracts/RouterV1.sol

@@ -51,11 +51,11 @@ contract RouterV1 {
     {
         IBondController bond = perp.getDepositBond();
 
-        BondTranches memory td;
+        BondTranches memory bt;
         uint256[] memory trancheAmts;
-        (td, trancheAmts, ) = bond.previewDeposit(collateralAmount);
+        (bt, trancheAmts, ) = bond.previewDeposit(collateralAmount);
 
-        return (bond, td.tranches, trancheAmts);
+        return (bond, bt.tranches, trancheAmts);
     }
 
     /// @notice Calculates the amount of perp tokens minted and fees for the operation.
@@ -100,7 +100,7 @@ contract RouterV1 {
         uint256 collateralAmount,
         uint256 feePaid
     ) external afterPerpStateUpdate(perp) {
-        BondTranches memory td = bond.getTranches();
+        BondTranches memory bt = bond.getTranches();
         IERC20Upgradeable collateralToken = IERC20Upgradeable(bond.collateralToken());
         IERC20Upgradeable feeToken = perp.feeToken();
 
@@ -119,18 +119,18 @@ contract RouterV1 {
         // approves fee to be spent to mint perp tokens
         _checkAndApproveMax(feeToken, address(perp), feePaid);
 
-        for (uint8 i = 0; i < td.tranches.length; i++) {
-            uint256 trancheAmt = td.tranches[i].balanceOf(address(this));
-            uint256 mintAmt = perp.computeMintAmt(td.tranches[i], trancheAmt);
+        for (uint8 i = 0; i < bt.tranches.length; i++) {
+            uint256 trancheAmt = bt.tranches[i].balanceOf(address(this));
+            uint256 mintAmt = perp.computeMintAmt(bt.tranches[i], trancheAmt);
             if (mintAmt > 0) {
                 // approves tranches to be spent
-                _checkAndApproveMax(td.tranches[i], address(perp), trancheAmt);
+                _checkAndApproveMax(bt.tranches[i], address(perp), trancheAmt);
 
                 // mints perp tokens using tranches
-                perp.deposit(td.tranches[i], trancheAmt);
+                perp.deposit(bt.tranches[i], trancheAmt);
             } else {
                 // transfers unused tranches back
-                td.tranches[i].safeTransfer(msg.sender, trancheAmt);
+                bt.tranches[i].safeTransfer(msg.sender, trancheAmt);
             }
         }
 
@@ -238,7 +238,7 @@ contract RouterV1 {
         RolloverBatch[] calldata rollovers,
         uint256 feePaid
     ) external afterPerpStateUpdate(perp) {
-        BondTranches memory td = bond.getTranches();
+        BondTranches memory bt = bond.getTranches();
         IERC20Upgradeable collateralToken = IERC20Upgradeable(bond.collateralToken());
         IERC20Upgradeable feeToken = perp.feeToken();
 
@@ -276,10 +276,10 @@ contract RouterV1 {
         }
 
         // transfers unused tranches back
-        for (uint8 i = 0; i < td.tranches.length; i++) {
-            uint256 trancheBalance = td.tranches[i].balanceOf(address(this));
+        for (uint8 i = 0; i < bt.tranches.length; i++) {
+            uint256 trancheBalance = bt.tranches[i].balanceOf(address(this));
             if (trancheBalance > 0) {
-                td.tranches[i].safeTransfer(msg.sender, trancheBalance);
+                bt.tranches[i].safeTransfer(msg.sender, trancheBalance);
             }
         }
 

spot-contracts/contracts/_interfaces/IPerpetualTranche.sol

@@ -110,6 +110,11 @@ interface IPerpetualTranche is IERC20Upgradeable {
     /// @return If the token is part of the reserve.
     function inReserve(IERC20Upgradeable token) external returns (bool);
 
+    /// @notice Fetches the reserve's token balance.
+    /// @param token The address of the tranche token held by the reserve.
+    /// @return The ERC-20 balance of the reserve token.
+    function getReserveTokenBalance(IERC20Upgradeable token) external returns (uint256);
+
     /// @notice Fetches the reserve's tranche token balance.
     /// @param tranche The address of the tranche token held by the reserve.
     /// @return The ERC-20 balance of the reserve tranche token.

spot-contracts/contracts/_utils/BondHelpers.sol

@@ -25,12 +25,12 @@ struct BondTranches {
  */
 library BondTranchesHelpers {
     /// @notice Iterates through the tranche data to find the seniority index of the given tranche.
-    /// @param td The tranche data object.
+    /// @param bt The tranche data object.
     /// @param t The address of the tranche to check.
     /// @return the index of the tranche in the tranches array.
-    function indexOf(BondTranches memory td, ITranche t) internal pure returns (uint8) {
-        for (uint8 i = 0; i < td.tranches.length; i++) {
-            if (td.tranches[i] == t) {
+    function indexOf(BondTranches memory bt, ITranche t) internal pure returns (uint8) {
+        for (uint8 i = 0; i < bt.tranches.length; i++) {
+            if (bt.tranches[i] == t) {
                 return i;
             }
         }
@@ -50,11 +50,11 @@ library TrancheHelpers {
     /// @return The collateral balance and the tranche token supply.
     function getTrancheCollateralization(ITranche t) internal view returns (uint256, uint256) {
         IBondController bond = IBondController(t.bond());
-        BondTranches memory td;
+        BondTranches memory bt;
         uint256[] memory collateralBalances;
         uint256[] memory trancheSupplies;
-        (td, collateralBalances, trancheSupplies) = BondHelpers.getTrancheCollateralizations(bond);
-        uint256 trancheIndex = BondTranchesHelpers.indexOf(td, t);
+        (bt, collateralBalances, trancheSupplies) = BondHelpers.getTrancheCollateralizations(bond);
+        uint256 trancheIndex = BondTranchesHelpers.indexOf(bt, t);
         return (collateralBalances[trancheIndex], trancheSupplies[trancheIndex]);
     }
 }
@@ -86,17 +86,17 @@ library BondHelpers {
     /// @param b The address of the bond contract.
     /// @return The tranche data.
     function getTranches(IBondController b) internal view returns (BondTranches memory) {
-        BondTranches memory td;
+        BondTranches memory bt;
         uint8 trancheCount = b.trancheCount().toUint8();
-        td.tranches = new ITranche[](trancheCount);
-        td.trancheRatios = new uint256[](trancheCount);
+        bt.tranches = new ITranche[](trancheCount);
+        bt.trancheRatios = new uint256[](trancheCount);
         // Max tranches per bond < 2**8 - 1
         for (uint8 i = 0; i < trancheCount; i++) {
             (ITranche t, uint256 ratio) = b.tranches(i);
-            td.tranches[i] = t;
-            td.trancheRatios[i] = ratio;
+            bt.tranches[i] = t;
+            bt.trancheRatios[i] = ratio;
         }
-        return td;
+        return bt;
     }
 
     /// @notice Given a bond, returns the tranche at the specified index.
@@ -122,29 +122,29 @@ library BondHelpers {
             uint256[] memory
         )
     {
-        BondTranches memory td = getTranches(b);
-        uint256[] memory trancheAmts = new uint256[](td.tranches.length);
-        uint256[] memory fees = new uint256[](td.tranches.length);
+        BondTranches memory bt = getTranches(b);
+        uint256[] memory trancheAmts = new uint256[](bt.tranches.length);
+        uint256[] memory fees = new uint256[](bt.tranches.length);
 
         uint256 totalDebt = b.totalDebt();
         uint256 collateralBalance = IERC20Upgradeable(b.collateralToken()).balanceOf(address(b));
         uint256 feeBps = b.feeBps();
 
-        for (uint8 i = 0; i < td.tranches.length; i++) {
-            trancheAmts[i] = collateralAmount.mulDiv(td.trancheRatios[i], TRANCHE_RATIO_GRANULARITY);
+        for (uint8 i = 0; i < bt.tranches.length; i++) {
+            trancheAmts[i] = collateralAmount.mulDiv(bt.trancheRatios[i], TRANCHE_RATIO_GRANULARITY);
             if (collateralBalance > 0) {
                 trancheAmts[i] = trancheAmts[i].mulDiv(totalDebt, collateralBalance);
             }
         }
 
         if (feeBps > 0) {
-            for (uint8 i = 0; i < td.tranches.length; i++) {
+            for (uint8 i = 0; i < bt.tranches.length; i++) {
                 fees[i] = trancheAmts[i].mulDiv(feeBps, BPS);
                 trancheAmts[i] -= fees[i];
             }
         }
 
-        return (td, trancheAmts, fees);
+        return (bt, trancheAmts, fees);
     }
 
     /// @notice Given a bond, for each tranche token retrieves the total collateral redeemable
@@ -162,24 +162,24 @@ library BondHelpers {
             uint256[] memory
         )
     {
-        BondTranches memory td = getTranches(b);
-        uint256[] memory collateralBalances = new uint256[](td.tranches.length);
-        uint256[] memory trancheSupplies = new uint256[](td.tranches.length);
+        BondTranches memory bt = getTranches(b);
+        uint256[] memory collateralBalances = new uint256[](bt.tranches.length);
+        uint256[] memory trancheSupplies = new uint256[](bt.tranches.length);
 
         // When the bond is mature, the collateral is transferred over to the individual tranche token contracts
         if (b.isMature()) {
-            for (uint8 i = 0; i < td.tranches.length; i++) {
-                trancheSupplies[i] = td.tranches[i].totalSupply();
-                collateralBalances[i] = IERC20Upgradeable(b.collateralToken()).balanceOf(address(td.tranches[i]));
+            for (uint8 i = 0; i < bt.tranches.length; i++) {
+                trancheSupplies[i] = bt.tranches[i].totalSupply();
+                collateralBalances[i] = IERC20Upgradeable(b.collateralToken()).balanceOf(address(bt.tranches[i]));
             }
-            return (td, collateralBalances, trancheSupplies);
+            return (bt, collateralBalances, trancheSupplies);
         }
 
         // Before the bond is mature, all the collateral is held by the bond contract
         uint256 bondCollateralBalance = IERC20Upgradeable(b.collateralToken()).balanceOf(address(b));
-        uint256 zTrancheIndex = td.tranches.length - 1;
-        for (uint8 i = 0; i < td.tranches.length; i++) {
-            trancheSupplies[i] = td.tranches[i].totalSupply();
+        uint256 zTrancheIndex = bt.tranches.length - 1;
+        for (uint8 i = 0; i < bt.tranches.length; i++) {
+            trancheSupplies[i] = bt.tranches[i].totalSupply();
 
             // a to y tranches
             if (i != zTrancheIndex) {
@@ -194,7 +194,7 @@ library BondHelpers {
             }
         }
 
-        return (td, collateralBalances, trancheSupplies);
+        return (bt, collateralBalances, trancheSupplies);
     }
 
     /// @notice For a given bond and user address, computes the maximum number of each of the bond's tranches
@@ -207,29 +207,29 @@ library BondHelpers {
         view
         returns (BondTranches memory, uint256[] memory)
     {
-        BondTranches memory td = getTranches(b);
-        uint256[] memory redeemableAmts = new uint256[](td.tranches.length);
+        BondTranches memory bt = getTranches(b);
+        uint256[] memory redeemableAmts = new uint256[](bt.tranches.length);
 
         // Calculate how many underlying assets could be redeemed from each tranche balance,
         // assuming other tranches are not an issue, and record the smallest amount.
         uint256 minUnderlyingOut = type(uint256).max;
         uint8 i;
-        for (i = 0; i < td.tranches.length; i++) {
-            uint256 d = td.tranches[i].balanceOf(u).mulDiv(TRANCHE_RATIO_GRANULARITY, td.trancheRatios[i]);
+        for (i = 0; i < bt.tranches.length; i++) {
+            uint256 d = bt.tranches[i].balanceOf(u).mulDiv(TRANCHE_RATIO_GRANULARITY, bt.trancheRatios[i]);
             if (d < minUnderlyingOut) {
                 minUnderlyingOut = d;
             }
 
             // if one of the balances is zero, we return
             if (minUnderlyingOut == 0) {
-                return (td, redeemableAmts);
+                return (bt, redeemableAmts);
             }
         }
 
-        for (i = 0; i < td.tranches.length; i++) {
-            redeemableAmts[i] = td.trancheRatios[i].mulDiv(minUnderlyingOut, TRANCHE_RATIO_GRANULARITY);
+        for (i = 0; i < bt.tranches.length; i++) {
+            redeemableAmts[i] = bt.trancheRatios[i].mulDiv(minUnderlyingOut, TRANCHE_RATIO_GRANULARITY);
         }
 
-        return (td, redeemableAmts);
+        return (bt, redeemableAmts);
     }
 }

spot-contracts/contracts/strategies/TrancheClassDiscountStrategy.sol

@@ -73,7 +73,7 @@ contract TrancheClassDiscountStrategy is IDiscountStrategy, OwnableUpgradeable {
     /// @return The class hash.
     function trancheClass(ITranche tranche) public view returns (bytes32) {
         IBondController bond = IBondController(tranche.bond());
-        BondTranches memory td = bond.getTranches();
-        return keccak256(abi.encode(bond.collateralToken(), td.trancheRatios, td.indexOf(tranche)));
+        BondTranches memory bt = bond.getTranches();
+        return keccak256(abi.encode(bond.collateralToken(), bt.trancheRatios, bt.indexOf(tranche)));
     }
 }

spot-contracts/contracts/test/BondHelpersTester.sol

@@ -13,7 +13,7 @@ contract BondHelpersTester {
         return b.secondsToMaturity();
     }
 
-    function getTranches(IBondController b) public view returns (BondTranches memory td) {
+    function getTranches(IBondController b) public view returns (BondTranches memory bt) {
         return b.getTranches();
     }
 
@@ -33,7 +33,7 @@ contract BondHelpersTester {
         public
         view
         returns (
-            BondTranches memory td,
+            BondTranches memory bt,
             uint256[] memory,
             uint256[] memory
         )
@@ -42,14 +42,14 @@ contract BondHelpersTester {
     }
 
     function indexOf(IBondController b, ITranche t) public view returns (uint8) {
-        BondTranches memory td = b.getTranches();
-        return td.indexOf(t);
+        BondTranches memory bt = b.getTranches();
+        return bt.indexOf(t);
     }
 
     function computeRedeemableTrancheAmounts(IBondController b, address u)
         public
         view
-        returns (BondTranches memory td, uint256[] memory)
+        returns (BondTranches memory bt, uint256[] memory)
     {
         return b.computeRedeemableTrancheAmounts(u);
     }