fix: SweepBadDebts first checks and aborts on nonzero collateral (#541)

* fix: SweepBadDebts first checks and aborts on nonzero collateral * suggestion Co-authored-by: Aleksandr Bezobchuk <[email protected]>
umee-network · Feb 11, 2022 · a0f0a23 · a0f0a23
1 parent 1424e22
commit a0f0a23
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Showing 2 changed files with 43 additions and 21 deletions.
diff --git a/x/leverage/keeper/iter.go b/x/leverage/keeper/iter.go
@@ -153,6 +153,21 @@ func (k Keeper) GetBorrowerCollateral(ctx sdk.Context, borrowerAddr sdk.AccAddre
 	return totalCollateral
 }
 
+// HasCollateral returns true if a borrower has any collateral.
+func (k Keeper) HasCollateral(ctx sdk.Context, borrowerAddr sdk.AccAddress) bool {
+	iter := sdk.KVStorePrefixIterator(
+		ctx.KVStore(k.storeKey),
+		types.KeyPrefixCollateralAmount,
+	)
+	defer iter.Close()
+
+	for ; iter.Valid(); iter.Next() {
+		// Stored collateral amounts are never zero, so this is enough
+		return true
+	}
+	return false
+}
+
 // GetEligibleLiquidationTargets returns a list of borrower addresses eligible for liquidation.
 func (k Keeper) GetEligibleLiquidationTargets(ctx sdk.Context) ([]sdk.AccAddress, error) {
 	prefix := types.KeyPrefixAdjustedBorrow
@@ -211,14 +226,20 @@ func (k Keeper) SweepBadDebts(ctx sdk.Context) error {
 		addr := types.AddressFromKey(key, prefix)
 		denom := types.DenomFromKeyWithAddress(key, prefix)
 
-		// attempt to repay a single address's debt in this denom
-		fullyRepaid, err := k.RepayBadDebt(ctx, addr, denom)
-		if err != nil {
-			return err
+		// first check if the borrower has gained collateral since the bad debt was identified
+		done := k.HasCollateral(ctx, addr)
+
+		// if collateral is still zero, attempt to repay a single address's debt in this denom
+		if !done {
+			var err error
+			done, err = k.RepayBadDebt(ctx, addr, denom)
+			if err != nil {
+				return err
+			}
 		}
-		if fullyRepaid {
-			// If the bad debt of this denom at the given address was fully repaid,
-			// clear the address|denom pair from the bad debt address list
+
+		// if collateral found or debt fully repaid, clear the bad debt entry for this address|denom
+		if done {
 			if err := k.setBadDebtAddress(ctx, addr, denom, false); err != nil {
 				return err
 			}

diff --git a/x/leverage/keeper/keeper_test.go b/x/leverage/keeper/keeper_test.go
@@ -655,21 +655,22 @@ func (s *IntegrationTestSuite) TestLiqudateBorrow_Valid() {
 }
 
 func (s *IntegrationTestSuite) TestRepayBadDebt() {
-	_, bumAddr := s.initBorrowScenario()
+	// Creating a lender so module account has some uumee
+	_ = s.setupAccount(umeeDenom, 200000000, 200000000, 0, false) // 200 umee
 
-	// The "bum" user from the init scenario is being used because it
-	// has no assets or collateral.
+	// Using an address with no assets
+	addr := s.setupAccount(umeeDenom, 0, 0, 0, false)
 
 	// Create an uncollateralized debt position
-	badDebt := sdk.NewInt64Coin(umeeapp.BondDenom, 100000000) // 100 umee
-	err := s.tk.SetBorrow(s.ctx, bumAddr, badDebt)
+	badDebt := sdk.NewInt64Coin(umeeDenom, 100000000) // 100 umee
+	err := s.tk.SetBorrow(s.ctx, addr, badDebt)
 	s.Require().NoError(err)
 
 	// Manually mark the bad debt for repayment
-	s.Require().NoError(s.tk.SetBadDebtAddress(s.ctx, bumAddr, umeeapp.BondDenom, true))
+	s.Require().NoError(s.tk.SetBadDebtAddress(s.ctx, addr, umeeDenom, true))
 
 	// Manually set reserves to 60 umee
-	reserve := sdk.NewInt64Coin(umeeapp.BondDenom, 60000000)
+	reserve := sdk.NewInt64Coin(umeeDenom, 60000000)
 	err = s.tk.SetReserveAmount(s.ctx, reserve)
 	s.Require().NoError(err)
 
@@ -678,15 +679,15 @@ func (s *IntegrationTestSuite) TestRepayBadDebt() {
 	s.Require().NoError(err)
 
 	// Confirm that a debt of 40 umee remains
-	remainingDebt := s.app.LeverageKeeper.GetBorrow(s.ctx, bumAddr, umeeapp.BondDenom)
-	s.Require().Equal(sdk.NewInt64Coin(umeeapp.BondDenom, 40000000), remainingDebt)
+	remainingDebt := s.app.LeverageKeeper.GetBorrow(s.ctx, addr, umeeDenom)
+	s.Require().Equal(sdk.NewInt64Coin(umeeDenom, 40000000), remainingDebt)
 
 	// Confirm that reserves are exhausted
-	remainingReserve := s.app.LeverageKeeper.GetReserveAmount(s.ctx, umeeapp.BondDenom)
+	remainingReserve := s.app.LeverageKeeper.GetReserveAmount(s.ctx, umeeDenom)
 	s.Require().Equal(sdk.ZeroInt(), remainingReserve)
 
 	// Manually set reserves to 70 umee
-	reserve = sdk.NewInt64Coin(umeeapp.BondDenom, 70000000)
+	reserve = sdk.NewInt64Coin(umeeDenom, 70000000)
 	err = s.tk.SetReserveAmount(s.ctx, reserve)
 	s.Require().NoError(err)
 
@@ -695,11 +696,11 @@ func (s *IntegrationTestSuite) TestRepayBadDebt() {
 	s.Require().NoError(err)
 
 	// Confirm that the debt is eliminated
-	remainingDebt = s.app.LeverageKeeper.GetBorrow(s.ctx, bumAddr, umeeapp.BondDenom)
-	s.Require().Equal(sdk.NewInt64Coin(umeeapp.BondDenom, 0), remainingDebt)
+	remainingDebt = s.app.LeverageKeeper.GetBorrow(s.ctx, addr, umeeDenom)
+	s.Require().Equal(sdk.NewInt64Coin(umeeDenom, 0), remainingDebt)
 
 	// Confirm that reserves are now at 30 umee
-	remainingReserve = s.app.LeverageKeeper.GetReserveAmount(s.ctx, umeeapp.BondDenom)
+	remainingReserve = s.app.LeverageKeeper.GetReserveAmount(s.ctx, umeeDenom)
 	s.Require().Equal(sdk.NewInt(30000000), remainingReserve)
 
 	// Sweep all bad debts - but there are none