feat: split collateralWeight into collateralWeight and liquidationThr…

…eshold (#627)

* collateral damage

* comment++

* sp

* comment++

* param name

* sp

* lint

* test fix

* Apply suggestions from code review

Co-authored-by: Aleksandr Bezobchuk <alexanderbez@users.noreply.github.com>

* lint++

* rename

* rename++

Co-authored-by: Aleksandr Bezobchuk <alexanderbez@users.noreply.github.com>

app/beta/test_helpers.go

@@ -88,6 +88,7 @@ func IntegrationTestNetworkConfig() network.Config {
 		Exponent:             6,
 		ReserveFactor:        sdk.MustNewDecFromStr("0.100000000000000000"),
 		CollateralWeight:     sdk.MustNewDecFromStr("0.050000000000000000"),
+		LiquidationThreshold: sdk.MustNewDecFromStr("0.050000000000000000"),
 		BaseBorrowRate:       sdk.MustNewDecFromStr("0.020000000000000000"),
 		KinkBorrowRate:       sdk.MustNewDecFromStr("0.200000000000000000"),
 		MaxBorrowRate:        sdk.MustNewDecFromStr("1.50000000000000000"),

proto/umee/leverage/v1beta1/leverage.proto

@@ -55,10 +55,19 @@ message Token {
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"collateral_weight\""
   ];
+
+  // The liquidation_threshold defines what amount of the total value of the asset
+  // can contribute to a user's liquidation threshold (above which they become
+  // eligible for liquidation).
+  string liquidation_threshold = 4 [
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+    (gogoproto.nullable)   = false,
+    (gogoproto.moretags)   = "yaml:\"liquidation_threshold\""
+  ];
 
   // The base_borrow_rate defines the base interest rate for borrowing this
   // asset.
-  string base_borrow_rate = 4 [
+  string base_borrow_rate = 5 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"base_borrow_rate\""
@@ -67,38 +76,38 @@ message Token {
   // The kink_borrow_rate defines the interest rate for borrowing this
   // asset when utilization is at the 'kink' utilization value as defined
   // on the utilization:interest graph.
-  string kink_borrow_rate = 5 [
+  string kink_borrow_rate = 6 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"kink_borrow_rate\""
   ];
 
   // The max_borrow_rate defines the interest rate for borrowing this
   // asset (seen when utilization is 100%).
-  string max_borrow_rate = 6 [
+  string max_borrow_rate = 7 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"max_borrow_rate\""
   ];
 
   // The kink_utilization_rate defines the borrow utilization rate for this
   // asset where the 'kink' on the utilization:interest graph occurs.
-  string kink_utilization_rate = 7 [
+  string kink_utilization_rate = 8 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"kink_utilization_rate\""
   ];
 
   // The liquidation_incentive determines the portion of bonus collateral of
   // a token type liquidators receive as a liquidation reward.
-  string liquidation_incentive = 8 [
+  string liquidation_incentive = 9 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false,
     (gogoproto.moretags)   = "yaml:\"liquidation_incentive\""
   ];
 
   // The symbol_denom and exponent are solely used to update the oracle's accept
   // list of allowed tokens.
-  string symbol_denom = 9 [(gogoproto.moretags) = "yaml:\"symbol_denom\""];
-  uint32 exponent     = 10 [(gogoproto.moretags) = "yaml:\"exponent\""];
+  string symbol_denom = 10 [(gogoproto.moretags) = "yaml:\"symbol_denom\""];
+  uint32 exponent     = 11 [(gogoproto.moretags) = "yaml:\"exponent\""];
 }

starport.ci.beta.yml

@@ -14,6 +14,7 @@ genesis:
           exponent: 6
           reserve_factor: "0.100000000000000000"
           collateral_weight: "0.050000000000000000"
+          liquidation_threshold: "0.050000000000000000"
           base_borrow_rate: "0.020000000000000000"
           kink_borrow_rate: "0.200000000000000000"
           max_borrow_rate: "1.50000000000000000"
@@ -23,7 +24,8 @@ genesis:
           symbol_denom: "ATOM"
           exponent: 6
           reserve_factor: "0.100000000000000000"
-          collateral_weight: "0.050000000000000000"
+          collateral_weight: "0.550000000000000000"
+          liquidation_threshold: "0.600000000000000000"
           base_borrow_rate: "0.020000000000000000"
           kink_borrow_rate: "0.200000000000000000"
           max_borrow_rate: "1.50000000000000000"

tests/e2e/e2e_setup_test.go

@@ -230,6 +230,7 @@ func (s *IntegrationTestSuite) initGenesis() {
 		Exponent:             6,
 		ReserveFactor:        sdk.MustNewDecFromStr("0.100000000000000000"),
 		CollateralWeight:     sdk.MustNewDecFromStr("0.050000000000000000"),
+		LiquidationThreshold: sdk.MustNewDecFromStr("0.050000000000000000"),
 		BaseBorrowRate:       sdk.MustNewDecFromStr("0.020000000000000000"),
 		KinkBorrowRate:       sdk.MustNewDecFromStr("0.200000000000000000"),
 		MaxBorrowRate:        sdk.MustNewDecFromStr("1.50000000000000000"),

x/leverage/client/cli/proposal_test.go

@@ -35,6 +35,7 @@ func TestParseUpdateRegistryProposal(t *testing.T) {
 			"base_denom": "uumee",
 			"reserve_factor": "0.1",
 			"collateral_weight": "0.05",
+			"liquidation_threshold": "0.05",
 			"base_borrow_rate": "0.02",
 			"kink_borrow_rate": "0.2",
 			"max_borrow_rate": "1.5",

x/leverage/client/cli/tx.go

@@ -274,6 +274,7 @@ Where proposal.json contains:
       "base_denom": "uumee",
       "reserve_factor": "0.1",
       "collateral_weight": "0.05",
+      "liquidation_threshold": "0.05",
       "base_borrow_rate": "0.02",
       "kink_borrow_rate": "0.2",
       "max_borrow_rate": "1.5",

x/leverage/client/tests/suite.go

@@ -137,6 +137,7 @@ func (s *IntegrationTestSuite) TestQueryAllRegisteredTokens() {
 						Exponent:             6,
 						ReserveFactor:        sdk.MustNewDecFromStr("0.1"),
 						CollateralWeight:     sdk.MustNewDecFromStr("0.05"),
+						LiquidationThreshold: sdk.MustNewDecFromStr("0.05"),
 						BaseBorrowRate:       sdk.MustNewDecFromStr("0.02"),
 						KinkBorrowRate:       sdk.MustNewDecFromStr("0.2"),
 						MaxBorrowRate:        sdk.MustNewDecFromStr("1.5"),

x/leverage/client/tests/util.go

@@ -140,7 +140,8 @@ func (s *IntegrationTestSuite) UpdateRegistry(
 	)
 }
 
-// updateCollateralWeight modifies the collateral weight of a registered token identified by baseDenom.
+// updateCollateralWeight modifies the collateral weight and liquidation threshold of a registered
+// token identified by baseDenom.
 func updateCollateralWeight(s *IntegrationTestSuite, baseDenom string, collateralWeight sdk.Dec) {
 	val := s.network.Validators[0]
 	clientCtx := s.network.Validators[0].ClientCtx
@@ -156,11 +157,12 @@ func updateCollateralWeight(s *IntegrationTestSuite, baseDenom string, collatera
 	resp := &types.QueryRegisteredTokensResponse{}
 	s.Require().NoError(clientCtx.Codec.UnmarshalJSON(out.Bytes(), resp), out.String())
 
-	// Replace the collateral weight of the selected token with the new value
+	// Replace the liquidation threshold and collateral weight of the selected token with the new value
 	newTokens := resp.GetRegistry()
 	for i := range newTokens {
 		if newTokens[i].BaseDenom == baseDenom {
 			newTokens[i].CollateralWeight = collateralWeight
+			newTokens[i].LiquidationThreshold = collateralWeight
 		}
 	}
 
@@ -172,7 +174,7 @@ func updateCollateralWeight(s *IntegrationTestSuite, baseDenom string, collatera
 		clientCtx,
 		types.NewUpdateRegistryProposal(
 			fmt.Sprintf("collateral weight update - %d", proposalCounter),
-			"update collateral weight to "+collateralWeight.String(),
+			fmt.Sprintf("update collateral weight and liquidation threshold to %s", collateralWeight.String()),
 			newTokens,
 		),
 		sdk.NewCoins(sdk.NewCoin(app.BondDenom, govtypes.DefaultMinDepositTokens)),

x/leverage/keeper/borrows.go

@@ -108,6 +108,38 @@ func (k Keeper) CalculateBorrowLimit(ctx sdk.Context, collateral sdk.Coins) (sdk
 	return limit, nil
 }
 
+// CalculateLiquidationLimit uses the price oracle to determine the liquidation limit
+// (in USD) provided by collateral sdk.Coins, using each token's uToken exchange rate and
+// liquidation threshold. An error is returned if any input coins are not uTokens or if value
+// calculation fails.
+func (k Keeper) CalculateLiquidationLimit(ctx sdk.Context, collateral sdk.Coins) (sdk.Dec, error) {
+	threshold := sdk.ZeroDec()
+
+	for _, coin := range collateral {
+		// convert uToken collateral to base assets
+		baseAsset, err := k.ExchangeUToken(ctx, coin)
+		if err != nil {
+			return sdk.ZeroDec(), err
+		}
+
+		// get USD value of base assets
+		value, err := k.TokenValue(ctx, baseAsset)
+		if err != nil {
+			return sdk.ZeroDec(), err
+		}
+
+		weight, err := k.GetLiquidationThreshold(ctx, baseAsset.Denom)
+		if err != nil {
+			return sdk.ZeroDec(), err
+		}
+
+		// add each liquidation threshold value to total
+		threshold = threshold.Add(value.Mul(weight))
+	}
+
+	return threshold, nil
+}
+
 // setBadDebtAddress sets or deletes an address in a denom's list of addresses with unpaid bad debt.
 func (k Keeper) setBadDebtAddress(ctx sdk.Context, addr sdk.AccAddress, denom string, hasDebt bool) error {
 	if err := sdk.ValidateDenom(denom); err != nil {

x/leverage/keeper/borrows_test.go

@@ -154,6 +154,7 @@ func (s *IntegrationTestSuite) TestDeriveBorrowUtilization() {
 		BaseDenom:            umeeDenom,
 		ReserveFactor:        sdk.MustNewDecFromStr("0"),
 		CollateralWeight:     sdk.MustNewDecFromStr("1"),
+		LiquidationThreshold: sdk.MustNewDecFromStr("1"),
 		BaseBorrowRate:       sdk.MustNewDecFromStr("0"),
 		KinkBorrowRate:       sdk.MustNewDecFromStr("0"),
 		MaxBorrowRate:        sdk.MustNewDecFromStr("0"),

x/leverage/keeper/iter.go

@@ -196,15 +196,15 @@ func (k Keeper) GetEligibleLiquidationTargets(ctx sdk.Context) ([]sdk.AccAddress
 			return err
 		}
 
-		// use collateral weights to compute borrow limit from enabled collateral
-		borrowLimit, err := k.CalculateBorrowLimit(ctx, collateral)
+		// compute liquidation limit from enabled collateral
+		liquidationLimit, err := k.CalculateLiquidationLimit(ctx, collateral)
 		if err != nil {
 			return err
 		}
 
-		// if the borrowLimit is smaller then the borrowValue
-		// the address is eligible to liquidation
-		if borrowLimit.LT(borrowValue) {
+		// If liquidation limit is smaller than borrowed value then the
+		// address is eligible for liquidation.
+		if liquidationLimit.LT(borrowValue) {
 			liquidationTargets = append(liquidationTargets, addr)
 		}
 

x/leverage/keeper/keeper.go

@@ -370,7 +370,7 @@ func (k Keeper) GetCollateralSetting(ctx sdk.Context, borrowerAddr sdk.AccAddres
 // LiquidateBorrow attempts to repay one of an eligible borrower's borrows (in part or in full) in exchange
 // for a selected denomination of uToken collateral, specified by its associated token denom. The liquidator
 // may also specify a minimum reward amount, again in base token denom that will be adjusted by uToken exchange
-// rate, they would accept for the specified repayment. If the borrower is not over their borrow limit, or
+// rate, they would accept for the specified repayment. If the borrower is not over their liquidation limit, or
 // the repayment or reward denominations are invalid, an error is returned. If the attempted repayment
 // is greater than the amount owed or the maximum that can be repaid due to parameters (close factor)
 // then a partial liquidation, equal to the maximum valid amount, is performed. The same occurs if the
@@ -399,20 +399,20 @@ func (k Keeper) LiquidateBorrow(
 		return sdk.ZeroInt(), sdk.ZeroInt(), err
 	}
 
-	// use collateral weights to compute borrow limit from enabled collateral
-	borrowLimit, err := k.CalculateBorrowLimit(ctx, collateral)
+	// compute liquidation limit from enabled collateral
+	liquidationLimit, err := k.CalculateLiquidationLimit(ctx, collateral)
 	if err != nil {
 		return sdk.ZeroInt(), sdk.ZeroInt(), err
 	}
 
 	// confirm borrower's eligibility for liquidation
-	if borrowLimit.GTE(borrowValue) {
+	if liquidationLimit.GTE(borrowValue) {
 		return sdk.ZeroInt(), sdk.ZeroInt(), sdkerrors.Wrap(types.ErrLiquidationIneligible, borrowerAddr.String())
 	}
 
 	// get reward-specific incentive and dynamic close factor
 	baseRewardDenom := desiredReward.Denom
-	liquidationIncentive, closeFactor, err := k.LiquidationParams(ctx, baseRewardDenom, borrowValue, borrowLimit)
+	liquidationIncentive, closeFactor, err := k.LiquidationParams(ctx, baseRewardDenom, borrowValue, liquidationLimit)
 	if err != nil {
 		return sdk.ZeroInt(), sdk.ZeroInt(), err
 	}
@@ -539,10 +539,15 @@ func (k Keeper) LiquidateBorrow(
 }
 
 // LiquidationParams computes dynamic liquidation parameters based on collateral denomination,
-// borrowed value, and borrow limit. Returns liquidationIncentive (the ratio of bonus collateral
+// borrowed value, and liquidation limit. Returns liquidationIncentive (the ratio of bonus collateral
 // awarded during Liquidate transactions, and closeFactor (the fraction of a borrower's total
 // borrowed value that can be repaid by a liquidator in a single liquidation event.)
-func (k Keeper) LiquidationParams(ctx sdk.Context, reward string, borrowed, limit sdk.Dec) (sdk.Dec, sdk.Dec, error) {
+func (k Keeper) LiquidationParams(
+	ctx sdk.Context,
+	reward string,
+	borrowed sdk.Dec,
+	limit sdk.Dec,
+) (sdk.Dec, sdk.Dec, error) {
 	if borrowed.IsNegative() {
 		return sdk.ZeroDec(), sdk.ZeroDec(), sdkerrors.Wrap(types.ErrBadValue, borrowed.String())
 	}
@@ -556,7 +561,7 @@ func (k Keeper) LiquidationParams(ctx sdk.Context, reward string, borrowed, limi
 		return sdk.ZeroDec(), sdk.ZeroDec(), err
 	}
 
-	// special case: If borrow limit is zero, close factor is always 1
+	// special case: If liquidation limit is zero, close factor is always 1
 	if limit.IsZero() {
 		return liquidationIncentive, sdk.OneDec(), nil
 	}