✨ auditor: support non-collateral markets

.changeset/brave-otter-glides.md

@@ -0,0 +1,5 @@
+---
+"@exactly/protocol": minor
+---
+
+✨ auditor: support non-collateral markets

contracts/Auditor.sol

@@ -129,7 +129,7 @@ contract Auditor is Initializable, AccessControlUpgradeable {
         vars.price = assetPrice(m.priceFeed);
 
         // sum all the collateral prices
-        sumCollateral += vars.balance.mulDivDown(vars.price, baseUnit).mulWadDown(adjustFactor);
+        if (!m.nonCollateral) sumCollateral += vars.balance.mulDivDown(vars.price, baseUnit).mulWadDown(adjustFactor);
 
         // sum all the debt
         sumDebtPlusEffects += vars.borrowBalance.mulDivUp(vars.price, baseUnit).divWadUp(adjustFactor);
@@ -138,7 +138,7 @@ contract Auditor is Initializable, AccessControlUpgradeable {
         if (market == marketToSimulate) {
           // calculate the effects of redeeming markets
           // (having less collateral is the same as having more debt for this calculation)
-          if (withdrawAmount != 0) {
+          if (withdrawAmount != 0 && !m.nonCollateral) {
             sumDebtPlusEffects += withdrawAmount.mulDivDown(vars.price, baseUnit).mulWadDown(adjustFactor);
           }
         }
@@ -179,8 +179,9 @@ contract Auditor is Initializable, AccessControlUpgradeable {
   /// @param account address of the account to check for possible shortfall.
   /// @param amount amount that the account wants to withdraw or transfer.
   function checkShortfall(Market market, address account, uint256 amount) public view virtual {
-    // if the account is not 'in' the market, bypass the liquidity check
-    if ((accountMarkets[account] & (1 << markets[market].index)) == 0) return;
+    // bypass the liquidity check if the account is not 'in' the market or it is disabled as collateral
+    MarketData storage m = markets[market];
+    if ((accountMarkets[account] & (1 << m.index)) == 0 || m.nonCollateral) return;
 
     // otherwise, perform a hypothetical liquidity check to guard against shortfall
     (uint256 collateral, uint256 debt) = accountLiquidity(account, market, amount);
@@ -224,10 +225,12 @@ contract Auditor is Initializable, AccessControlUpgradeable {
         base.totalDebt += value;
         base.adjustedDebt += value.divWadUp(m.adjustFactor);
 
-        value = collateral.mulDivDown(m.price, m.baseUnit);
-        base.totalCollateral += value;
-        base.adjustedCollateral += value.mulWadDown(m.adjustFactor);
-        if (market == seizeMarket) base.seizeAvailable = value;
+        if (!marketData.nonCollateral) {
+          value = collateral.mulDivDown(m.price, m.baseUnit);
+          base.totalCollateral += value;
+          base.adjustedCollateral += value.mulWadDown(m.adjustFactor);
+          if (market == seizeMarket) base.seizeAvailable = value;
+        }
       }
       unchecked {
         ++i;
@@ -329,8 +332,10 @@ contract Auditor is Initializable, AccessControlUpgradeable {
       if (marketMap & 1 != 0) {
         Market market = marketList[i];
         MarketData storage m = markets[market];
-        uint256 assets = market.maxWithdraw(account);
-        if (assets.mulDivDown(assetPrice(m.priceFeed), 10 ** m.decimals).mulWadDown(m.adjustFactor) > 0) return;
+        if (!m.nonCollateral) {
+          uint256 assets = market.maxWithdraw(account);
+          if (assets.mulDivDown(assetPrice(m.priceFeed), 10 ** m.decimals).mulWadDown(m.adjustFactor) > 0) return;
+        }
       }
       unchecked {
         ++i;
@@ -368,10 +373,12 @@ contract Auditor is Initializable, AccessControlUpgradeable {
   /// @param market market to add to the protocol.
   /// @param priceFeed address of Chainlink's Price Feed aggregator used to query the asset price in base.
   /// @param adjustFactor market's adjust factor for the underlying asset.
+  /// @param nonCollateral true to list the market as ineligible as collateral.
   function enableMarket(
     Market market,
     IPriceFeed priceFeed,
-    uint128 adjustFactor
+    uint128 adjustFactor,
+    bool nonCollateral
   ) external onlyRole(DEFAULT_ADMIN_ROLE) {
     if (market.auditor() != this) revert AuditorMismatch();
     if (markets[market].isListed) revert MarketAlreadyListed();
@@ -383,14 +390,16 @@ contract Auditor is Initializable, AccessControlUpgradeable {
       adjustFactor: adjustFactor,
       decimals: decimals,
       index: uint8(marketList.length),
-      priceFeed: priceFeed
+      priceFeed: priceFeed,
+      nonCollateral: nonCollateral
     });
 
     marketList.push(market);
 
     emit MarketListed(market, decimals);
     emit PriceFeedSet(market, priceFeed);
     emit AdjustFactorSet(market, adjustFactor);
+    emit NonCollateralSet(market, nonCollateral);
   }
 
   /// @notice Sets the adjust factor for a certain market.
@@ -403,6 +412,21 @@ contract Auditor is Initializable, AccessControlUpgradeable {
     emit AdjustFactorSet(market, adjustFactor);
   }
 
+  /// @notice Sets whether a market's floating supply is ineligible as collateral.
+  /// @dev Disabling a market as collateral leaves positions that rely on it unhealthy and unliquidatable. The balance
+  /// stops counting as collateral, is excluded from the seizable set so liquidation reverts with `ZeroRepay`, and stays
+  /// freely withdrawable by its owner. The remaining debt is then liable to be cleared as bad debt against
+  /// `earningsAccumulator`. Do not enable this flag on a market with outstanding collateral-backed debt without first
+  /// winding that exposure down.
+  /// @param market address of the market to change collateral eligibility for.
+  /// @param nonCollateral true to make the market ineligible as collateral.
+  function setNonCollateral(Market market, bool nonCollateral) external onlyRole(DEFAULT_ADMIN_ROLE) {
+    if (!markets[market].isListed) revert MarketNotListed();
+
+    markets[market].nonCollateral = nonCollateral;
+    emit NonCollateralSet(market, nonCollateral);
+  }
+
   /// @notice Sets the Chainlink Price Feed Aggregator source for a market.
   /// @param market market address of the asset.
   /// @param priceFeed address of Chainlink's Price Feed aggregator used to query the asset price in base.
@@ -437,6 +461,11 @@ contract Auditor is Initializable, AccessControlUpgradeable {
   /// @param account address of the account that just left a market.
   event MarketExited(Market indexed market, address indexed account);
 
+  /// @notice Emitted when a market's collateral eligibility is changed by admin.
+  /// @param market address of the market whose collateral eligibility changed.
+  /// @param nonCollateral true if the market is now ineligible as collateral.
+  event NonCollateralSet(Market indexed market, bool nonCollateral);
+
   /// @notice Emitted when a adjust factor is changed by admin.
   /// @param market address of the market that has a new adjust factor.
   /// @param adjustFactor adjust factor for the underlying asset.
@@ -452,17 +481,20 @@ contract Auditor is Initializable, AccessControlUpgradeable {
   event PriceFeedSet(Market indexed market, IPriceFeed indexed priceFeed);
 
   /// @notice Stores the market parameters used for liquidity calculations.
-  /// @param adjustFactor used to asses the lending power of the market's underlying asset.
+  /// @param adjustFactor used to assess the borrowing and lending power of the market's underlying asset.
   /// @param decimals number of decimals of the market's underlying asset.
   /// @param index index of the market in the `marketList`.
   /// @param isListed true if the market is enabled.
   /// @param priceFeed address of the price feed used to query the asset's price.
+  /// @param nonCollateral true if the market's floating supply is ineligible as collateral.
+  // solhint-disable-next-line gas-struct-packing
   struct MarketData {
     uint128 adjustFactor;
     uint8 decimals;
     uint8 index;
     bool isListed;
     IPriceFeed priceFeed;
+    bool nonCollateral;
   }
 
   /// @notice Stores the liquidator and lenders factors used in liquidations to calculate the amount to seize.

contracts/periphery/DebtManager.sol

@@ -496,7 +496,7 @@ contract DebtManager is Initializable {
   }
 
   function checkMarket(Market market) internal view {
-    (, , , bool listed, ) = auditor.markets(market);
+    (, , , bool listed, , ) = auditor.markets(market);
     if (!listed) revert MarketNotListed();
   }
 

contracts/periphery/DebtPreviewer.sol

@@ -65,8 +65,9 @@ contract DebtPreviewer {
   ) internal view returns (uint256) {
     MinDepositVars memory vars;
     Auditor auditor = debtManager.auditor();
-    (vars.adjustFactorIn, vars.decimalsIn, , , vars.priceFeedIn) = auditor.markets(marketDeposit);
-    (vars.adjustFactorOut, vars.decimalsOut, , , vars.priceFeedOut) = auditor.markets(marketBorrow);
+    (vars.adjustFactorIn, vars.decimalsIn, , , vars.priceFeedIn, vars.nonCollateral) = auditor.markets(marketDeposit);
+    if (vars.nonCollateral) return 0;
+    (vars.adjustFactorOut, vars.decimalsOut, , , vars.priceFeedOut, ) = auditor.markets(marketBorrow);
 
     return
       minHealthFactor
@@ -182,8 +183,8 @@ contract DebtPreviewer {
     uint256 amountIn
   ) internal view returns (uint256) {
     Auditor auditor = debtManager.auditor();
-    (, uint256 decimalsOut, , , IPriceFeed priceFeedOut) = auditor.markets(marketBorrow);
-    (, uint256 decimalsIn, , , IPriceFeed priceFeedIn) = auditor.markets(marketDeposit);
+    (, uint256 decimalsOut, , , IPriceFeed priceFeedOut, ) = auditor.markets(marketBorrow);
+    (, uint256 decimalsIn, , , IPriceFeed priceFeedIn, ) = auditor.markets(marketDeposit);
     return
       amountIn.mulDivDown(auditor.assetPrice(priceFeedIn), 10 ** decimalsIn).mulDivDown(
         10 ** decimalsOut,
@@ -206,8 +207,9 @@ contract DebtPreviewer {
   ) internal view returns (uint256) {
     Auditor auditor = debtManager.auditor();
     MaxRatioVars memory mr;
-    (mr.adjustFactorIn, , , , mr.priceFeedIn) = auditor.markets(marketDeposit);
-    (mr.adjustFactorOut, , , , ) = auditor.markets(marketBorrow);
+    (mr.adjustFactorIn, , , , mr.priceFeedIn, mr.nonCollateral) = auditor.markets(marketDeposit);
+    if (mr.nonCollateral) return 1e18;
+    (mr.adjustFactorOut, , , , , ) = auditor.markets(marketBorrow);
     uint256 isolatedMaxRatio = minHealthFactor.divWadDown(
       minHealthFactor - mr.adjustFactorIn.mulWadDown(mr.adjustFactorOut)
     );
@@ -220,7 +222,7 @@ contract DebtPreviewer {
         Auditor.MarketData memory md;
         Auditor.AccountLiquidity memory vars;
         mr.market = auditor.marketList(mr.i);
-        (md.adjustFactor, md.decimals, , , md.priceFeed) = auditor.markets(mr.market);
+        (md.adjustFactor, md.decimals, , , md.priceFeed, md.nonCollateral) = auditor.markets(mr.market);
         (vars.balance, vars.borrowBalance) = mr.market.accountSnapshot(account);
         vars.price = auditor.assetPrice(md.priceFeed);
         mr.baseUnit = 10 ** md.decimals;
@@ -232,7 +234,7 @@ contract DebtPreviewer {
         } else {
           mr.adjustedDebt += vars.borrowBalance.mulDivUp(vars.price, mr.baseUnit).divWadUp(md.adjustFactor);
         }
-        if (mr.market != marketDeposit) {
+        if (mr.market != marketDeposit && !md.nonCollateral) {
           mr.adjustedCollateral += vars.balance.mulDivDown(vars.price, mr.baseUnit).mulWadDown(md.adjustFactor);
         }
       }
@@ -241,14 +243,19 @@ contract DebtPreviewer {
       }
     }
 
+    uint256 collateral = mr.adjustedCollateral.mulWadDown(mr.adjustFactorOut) +
+      minHealthFactor.mulWadDown(mr.principalUSD);
+    uint256 debt = minHealthFactor.mulWadDown(mr.adjustedDebt.mulWadDown(mr.adjustFactorOut));
+    if (debt >= collateral) return 1e18;
     return
-      Math.min(
-        (mr.adjustedCollateral.mulWadDown(mr.adjustFactorOut) +
-          minHealthFactor.mulWadDown(mr.principalUSD) -
-          minHealthFactor.mulWadDown(mr.adjustedDebt.mulWadDown(mr.adjustFactorOut))).divWadDown(
+      Math.max(
+        Math.min(
+          (collateral - debt).divWadDown(
             mr.principalUSD.mulWadDown(minHealthFactor - mr.adjustFactorIn.mulWadDown(mr.adjustFactorOut))
           ),
-        isolatedMaxRatio
+          isolatedMaxRatio
+        ),
+        1e18
       );
   }
 
@@ -275,19 +282,23 @@ contract DebtPreviewer {
     if (mw.principal <= 0) return 0;
 
     mw.auditor = debtManager.auditor();
+    (, , , , , mw.nonCollateral) = mw.auditor.markets(marketDeposit);
+    if (mw.nonCollateral) return uint256(mw.principal);
     Auditor.MarketData memory md;
     Auditor.AccountLiquidity memory vars;
     mw.marketMap = mw.auditor.accountMarkets(account);
     mw.borrowAssets = floatingBorrowAssets(marketBorrow, account);
     for (mw.i = 0; mw.marketMap != 0; mw.marketMap >>= 1) {
       if (mw.marketMap & 1 != 0) {
         mw.market = mw.auditor.marketList(mw.i);
-        (md.adjustFactor, md.decimals, , , md.priceFeed) = mw.auditor.markets(mw.market);
+        (md.adjustFactor, md.decimals, , , md.priceFeed, md.nonCollateral) = mw.auditor.markets(mw.market);
         uint256 baseUnit = 10 ** md.decimals;
         (vars.balance, vars.borrowBalance) = mw.market.accountSnapshot(account);
         vars.price = mw.auditor.assetPrice(md.priceFeed);
         {
-          mw.memAdjColl = vars.balance.mulDivDown(vars.price, baseUnit).mulWadDown(md.adjustFactor);
+          mw.memAdjColl = md.nonCollateral
+            ? 0
+            : vars.balance.mulDivDown(vars.price, baseUnit).mulWadDown(md.adjustFactor);
           mw.memAdjDebt = vars.borrowBalance.mulDivDown(vars.price, baseUnit).divWadDown(md.adjustFactor);
           mw.adjustedCollateral += mw.memAdjColl;
 
@@ -312,13 +323,14 @@ contract DebtPreviewer {
       }
     }
     {
-      (mw.adjustFactorIn, , , , mw.priceFeedIn) = mw.auditor.markets(marketDeposit);
-      (mw.adjustFactorOut, , , , ) = mw.auditor.markets(marketBorrow);
+      (mw.adjustFactorIn, , , , mw.priceFeedIn, ) = mw.auditor.markets(marketDeposit);
+      (mw.adjustFactorOut, , , , , ) = mw.auditor.markets(marketBorrow);
       mw.memOtherDebt = mw.otherDebt.mulWadDown(mw.adjustFactorOut).mulWadDown(minHealthFactor);
       mw.memOtherCollateral = (mw.otherCollateral).mulWadDown(mw.adjustFactorOut);
     }
 
     if (mw.memOtherDebt <= mw.memOtherCollateral) {
+      if (mw.adjustedDebt + mw.adjPrincipalForRepay >= mw.adjustedCollateral + mw.adjustedRepay) return 0;
       return
         Math.min(
           Math
@@ -332,15 +344,14 @@ contract DebtPreviewer {
         );
     }
 
-    return
-      uint256(mw.principal) -
-      (mw.memOtherDebt - mw.memOtherCollateral)
-        .divWadDown(
-          mw.adjustFactorIn.mulWadDown(ratio).mulWadDown(mw.adjustFactorOut) +
-            minHealthFactor -
-            ratio.mulWadDown(minHealthFactor)
-        )
-        .mulDivDown(10 ** marketDeposit.decimals(), mw.auditor.assetPrice(mw.priceFeedIn));
+    uint256 support = mw.adjustFactorIn.mulWadDown(ratio).mulWadDown(mw.adjustFactorOut) + minHealthFactor;
+    uint256 ratioDebt = ratio.mulWadDown(minHealthFactor);
+    if (ratioDebt >= support) return 0;
+    uint256 requiredPrincipal = (mw.memOtherDebt - mw.memOtherCollateral).divWadDown(support - ratioDebt).mulDivDown(
+      10 ** marketDeposit.decimals(),
+      mw.auditor.assetPrice(mw.priceFeedIn)
+    );
+    return uint256(mw.principal) > requiredPrincipal ? uint256(mw.principal) - requiredPrincipal : 0;
   }
 
   /// @notice Calculates the crossed principal amount for a given `account` in the input and output markets.
@@ -353,8 +364,8 @@ contract DebtPreviewer {
     IPriceFeed priceFeedIn;
     IPriceFeed priceFeedOut;
     Auditor auditor = debtManager.auditor();
-    (, decimalsIn, , , priceFeedIn) = auditor.markets(marketDeposit);
-    (, decimalsOut, , , priceFeedOut) = auditor.markets(marketBorrow);
+    (, decimalsIn, , , priceFeedIn, ) = auditor.markets(marketDeposit);
+    (, decimalsOut, , , priceFeedOut, ) = auditor.markets(marketBorrow);
 
     return
       int256(marketDeposit.maxWithdraw(account)) -
@@ -469,7 +480,7 @@ contract DebtPreviewer {
     r.controller = market.rewardsController();
     Auditor auditor = debtManager.auditor();
     if (address(r.controller) != address(0)) {
-      (, r.underlyingDecimals, , , r.underlyingPriceFeed) = auditor.markets(market);
+      (, r.underlyingDecimals, , , r.underlyingPriceFeed, ) = auditor.markets(market);
       unchecked {
         r.underlyingBaseUnit = 10 ** r.underlyingDecimals;
       }
@@ -578,6 +589,7 @@ struct Limit {
 
 struct MaxRatioVars {
   uint256 i;
+  bool nonCollateral;
   uint256 baseUnit;
   uint256 marketMap;
   uint256 principalUSD;
@@ -592,6 +604,7 @@ struct MaxRatioVars {
 struct MaxWithdrawVars {
   uint256 i;
   int256 principal;
+  bool nonCollateral;
   uint256 marketMap;
   uint256 otherDebt;
   uint256 memAdjDebt;
@@ -619,6 +632,7 @@ struct MinDepositVars {
   IPriceFeed priceFeedIn;
   uint256 adjustFactorOut;
   IPriceFeed priceFeedOut;
+  bool nonCollateral;
 }
 
 struct Rates {

contracts/periphery/DebtRoller.sol

@@ -99,7 +99,7 @@ contract DebtRoller is IFlashLoanRecipient, Initializable, AccessControlUpgradea
   }
 
   function _checkMarket(Market market) internal view {
-    (, , , bool listed, ) = auditor.markets(market);
+    (, , , bool listed, , ) = auditor.markets(market);
     if (!listed) revert NotMarket();
   }
 }

contracts/periphery/InstallmentsRouter.sol

@@ -128,7 +128,7 @@ contract InstallmentsRouter {
   /// @notice Reverts if the Market is not listed by the Auditor.
   /// @param market The Market to check.
   function checkMarket(Market market) internal view {
-    (, , , bool listed, ) = auditor.markets(market);
+    (, , , bool listed, , ) = auditor.markets(market);
     if (!listed) revert MarketNotListed();
   }