diff --git a/buidler.config.ts b/buidler.config.ts
index 9db632a2..03f42645 100644
--- a/buidler.config.ts
+++ b/buidler.config.ts
@@ -9,7 +9,8 @@ usePlugin('buidler-typechain');
usePlugin('solidity-coverage');
usePlugin('@nomiclabs/buidler-waffle');
usePlugin('@nomiclabs/buidler-etherscan');
-usePlugin('buidler-gas-reporter');
+//usePlugin('buidler-gas-reporter');
+
const DEFAULT_BLOCK_GAS_LIMIT = 10000000;
const DEFAULT_GAS_PRICE = 10;
const HARDFORK = 'istanbul';
diff --git a/contracts/tokenization/StableDebtToken.sol b/contracts/tokenization/StableDebtToken.sol
index 6401bfc9..fe352b32 100644
--- a/contracts/tokenization/StableDebtToken.sol
+++ b/contracts/tokenization/StableDebtToken.sol
@@ -167,6 +167,10 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
uint256 previousSupply = totalSupply();
+ //since the total supply and each single user debt accrue separately,
+ //there might be accumulation errors so that the last borrower repaying
+ //might actually try to repay more than the available debt supply.
+ //in this case we simply set the total supply and the avg stable rate to 0
if (previousSupply <= amount) {
_avgStableRate = 0;
_totalSupply = 0;
@@ -232,32 +236,51 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
);
}
+ /**
+ * @dev returns the principal, total supply and the average borrow rate
+ **/
function getSupplyData() public override view returns (uint256, uint256, uint256) {
uint256 avgRate = _avgStableRate;
return (super.totalSupply(), _calcTotalSupply(avgRate), avgRate);
}
+ /**
+ * @dev returns the the total supply and the average stable rate
+ **/
function getTotalSupplyAndAvgRate() public override view returns (uint256, uint256) {
uint256 avgRate = _avgStableRate;
return (_calcTotalSupply(avgRate), avgRate);
}
+ /**
+ * @dev returns the total supply
+ **/
function totalSupply() public override view returns (uint256) {
return _calcTotalSupply(_avgStableRate);
}
-
+
+ /**
+ * @dev returns the timestamp at which the total supply was updated
+ **/
function getTotalSupplyLastUpdated() public override view returns(uint40) {
return _totalSupplyTimestamp;
}
/**
* @dev Returns the principal debt balance of the user from
+ * @param user the user
* @return The debt balance of the user since the last burn/mint action
**/
function principalBalanceOf(address user) external virtual override view returns (uint256) {
return super.balanceOf(user);
}
+
+ /**
+ * @dev calculates the total supply
+ * @param avgRate the average rate at which calculate the total supply
+ * @return The debt balance of the user since the last burn/mint action
+ **/
function _calcTotalSupply(uint256 avgRate) internal view returns(uint256) {
uint256 principalSupply = super.totalSupply();
@@ -273,6 +296,12 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
return principalSupply.rayMul(cumulatedInterest);
}
+ /**
+ * @dev mints stable debt tokens to an user
+ * @param account the account receiving the debt tokens
+ * @param amount the amount being minted
+ * @param oldTotalSupply the total supply before the minting event
+ **/
function _mint(address account, uint256 amount, uint256 oldTotalSupply) internal {
uint256 oldAccountBalance = _balances[account];
@@ -283,9 +312,14 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
}
}
+ /**
+ * @dev burns stable debt tokens of an user
+ * @param account the user getting his debt burned
+ * @param amount the amount being burned
+ * @param oldTotalSupply the total supply before the burning event
+ **/
function _burn(address account, uint256 amount, uint256 oldTotalSupply) internal {
-
uint256 oldAccountBalance = _balances[account];
_balances[account] = oldAccountBalance.sub(amount, 'ERC20: burn amount exceeds balance');
diff --git a/test/helpers/actions.ts b/test/helpers/actions.ts
index 3e60955d..ba874e6e 100644
--- a/test/helpers/actions.ts
+++ b/test/helpers/actions.ts
@@ -375,6 +375,12 @@ export const borrow = async (
txCost
);
+ console.log("total stable debt actual: ", reserveDataAfter.totalStableDebt.toFixed());
+ console.log("total stable debt expected: ", expectedReserveData.totalStableDebt.toFixed());
+
+ console.log("total variable debt actual: ", reserveDataAfter.totalVariableDebt.toFixed());
+ console.log("total variable debt expected: ", expectedReserveData.totalVariableDebt.toFixed());
+
expectEqual(reserveDataAfter, expectedReserveData);
expectEqual(userDataAfter, expectedUserData);
@@ -479,6 +485,14 @@ export const repay = async (
txCost
);
+
+ console.log("total stable debt actual: ", reserveDataAfter.totalStableDebt.toFixed());
+ console.log("total stable debt expected: ", expectedReserveData.totalStableDebt.toFixed());
+
+ console.log("total variable debt actual: ", reserveDataAfter.totalVariableDebt.toFixed());
+ console.log("total variable debt expected: ", expectedReserveData.totalVariableDebt.toFixed());
+
+
expectEqual(reserveDataAfter, expectedReserveData);
expectEqual(userDataAfter, expectedUserData);
@@ -741,9 +755,12 @@ export const getContractsData = async (
sender?: string
) => {
const {pool} = testEnv;
- const reserveData = await getReserveData(pool, reserve);
- const userData = await getUserData(pool, reserve, user, sender || user);
- const timestamp = await timeLatest();
+
+ const [userData, reserveData, timestamp] = await Promise.all([
+ getUserData(pool, reserve, user, sender || user),
+ getReserveData(pool, reserve),
+ timeLatest(),
+ ]);
return {
reserveData,
diff --git a/test/helpers/utils/calculations.ts b/test/helpers/utils/calculations.ts
index 795dbaa3..3cd05b69 100644
--- a/test/helpers/utils/calculations.ts
+++ b/test/helpers/utils/calculations.ts
@@ -97,6 +97,8 @@ export const calcExpectedUserDataAfterWithdraw = (
currentTimestamp: BigNumber,
txCost: BigNumber
): UserReserveData => {
+ console.log('Checking withdraw');
+
const expectedUserData = <UserReserveData>{};
const aTokenBalance = calcExpectedATokenBalance(
@@ -183,7 +185,9 @@ export const calcExpectedReserveDataAfterDeposit = (
);
expectedReserveData.totalStableDebt = calcExpectedTotalStableDebt(
- reserveDataBeforeAction,
+ reserveDataBeforeAction.principalStableDebt,
+ reserveDataBeforeAction.averageStableBorrowRate,
+ reserveDataBeforeAction.lastUpdateTimestamp,
txTimestamp
);
expectedReserveData.totalVariableDebt = calcExpectedTotalVariableDebt(
@@ -252,7 +256,9 @@ export const calcExpectedReserveDataAfterWithdraw = (
);
expectedReserveData.totalStableDebt = calcExpectedTotalStableDebt(
- reserveDataBeforeAction,
+ reserveDataBeforeAction.principalStableDebt,
+ reserveDataBeforeAction.averageStableBorrowRate,
+ reserveDataBeforeAction.lastUpdateTimestamp,
txTimestamp
);
expectedReserveData.totalVariableDebt = calcExpectedTotalVariableDebt(
@@ -313,33 +319,71 @@ export const calcExpectedReserveDataAfterBorrow = (
expectedReserveData.lastUpdateTimestamp = txTimestamp;
if (borrowRateMode == RateMode.Stable) {
+
expectedReserveData.scaledVariableDebt = reserveDataBeforeAction.scaledVariableDebt;
- expectedReserveData.totalVariableDebt = reserveDataBeforeAction.scaledVariableDebt.rayMul(
- expectedReserveData.variableBorrowIndex
+ const expectedVariableDebtAfterTx = calcExpectedTotalVariableDebt(
+ reserveDataBeforeAction,
+ txTimestamp
);
+ const expectedStableDebtUntilTx = calcExpectedTotalStableDebt(
+ reserveDataBeforeAction.principalStableDebt,
+ reserveDataBeforeAction.averageStableBorrowRate,
+ reserveDataBeforeAction.lastUpdateTimestamp,
+ txTimestamp
+ );
+
+ expectedReserveData.principalStableDebt = expectedStableDebtUntilTx.plus(amountBorrowedBN);
+
expectedReserveData.averageStableBorrowRate = calcExpectedAverageStableBorrowRate(
reserveDataBeforeAction.averageStableBorrowRate,
- reserveDataBeforeAction.totalStableDebt,
+ expectedStableDebtUntilTx,
amountBorrowedBN,
reserveDataBeforeAction.stableBorrowRate
);
- expectedReserveData.principalStableDebt = reserveDataBeforeAction.totalStableDebt.plus(
- amountBorrowedBN
+ const totalLiquidityAfterTx = expectedReserveData.availableLiquidity
+ .plus(expectedReserveData.principalStableDebt)
+ .plus(expectedVariableDebtAfterTx);
+
+ const utilizationRateAfterTx = calcExpectedUtilizationRate(
+ expectedReserveData.principalStableDebt, //the expected principal debt is the total debt immediately after the tx
+ expectedVariableDebtAfterTx,
+ totalLiquidityAfterTx
);
+ const ratesAfterTx = calcExpectedInterestRates(
+ reserveDataBeforeAction.symbol,
+ reserveDataBeforeAction.marketStableRate,
+ utilizationRateAfterTx,
+ expectedReserveData.principalStableDebt,
+ expectedVariableDebtAfterTx,
+ expectedReserveData.averageStableBorrowRate
+ );
+
+ expectedReserveData.liquidityRate = ratesAfterTx[0];
+
+ expectedReserveData.stableBorrowRate = ratesAfterTx[1];
+
+ expectedReserveData.variableBorrowRate = ratesAfterTx[2];
+
expectedReserveData.totalStableDebt = calcExpectedTotalStableDebt(
- {
- ...reserveDataBeforeAction,
- principalStableDebt: expectedReserveData.principalStableDebt,
- averageStableBorrowRate: expectedReserveData.averageStableBorrowRate,
- lastUpdateTimestamp: txTimestamp,
- },
+ expectedReserveData.principalStableDebt,
+ expectedReserveData.averageStableBorrowRate,
+ txTimestamp,
currentTimestamp
);
+ expectedReserveData.totalVariableDebt = reserveDataBeforeAction.scaledVariableDebt.rayMul(
+ calcExpectedReserveNormalizedDebt(
+ expectedReserveData.variableBorrowRate,
+ expectedReserveData.variableBorrowIndex,
+ txTimestamp,
+ currentTimestamp
+ )
+ );
+
expectedReserveData.totalLiquidity = expectedReserveData.availableLiquidity
.plus(expectedReserveData.totalVariableDebt)
.plus(expectedReserveData.totalStableDebt);
@@ -349,21 +393,6 @@ export const calcExpectedReserveDataAfterBorrow = (
expectedReserveData.totalVariableDebt,
expectedReserveData.totalLiquidity
);
-
- const rates = calcExpectedInterestRates(
- reserveDataBeforeAction.symbol,
- reserveDataBeforeAction.marketStableRate,
- expectedReserveData.utilizationRate,
- expectedReserveData.totalStableDebt,
- expectedReserveData.totalVariableDebt,
- expectedReserveData.averageStableBorrowRate
- );
-
- expectedReserveData.liquidityRate = rates[0];
-
- expectedReserveData.stableBorrowRate = rates[1];
-
- expectedReserveData.variableBorrowRate = rates[2];
} else {
expectedReserveData.principalStableDebt = reserveDataBeforeAction.principalStableDebt;
@@ -406,7 +435,12 @@ export const calcExpectedReserveDataAfterBorrow = (
expectedReserveData.variableBorrowRate = rates[2];
expectedReserveData.totalVariableDebt = expectedReserveData.scaledVariableDebt.rayMul(
- calcExpectedReserveNormalizedDebt(expectedReserveData, currentTimestamp)
+ calcExpectedReserveNormalizedDebt(
+ expectedReserveData.variableBorrowRate,
+ expectedReserveData.variableBorrowIndex,
+ txTimestamp,
+ currentTimestamp
+ )
);
expectedReserveData.totalLiquidity = expectedReserveData.availableLiquidity
@@ -469,16 +503,32 @@ export const calcExpectedReserveDataAfterRepay = (
);
if (borrowRateMode == RateMode.Stable) {
- expectedReserveData.principalStableDebt = expectedReserveData.totalStableDebt = reserveDataBeforeAction.totalStableDebt.minus(
- amountRepaidBN
+ const expectedDebt = calcExpectedTotalStableDebt(
+ reserveDataBeforeAction.principalStableDebt,
+ reserveDataBeforeAction.averageStableBorrowRate,
+ reserveDataBeforeAction.lastUpdateTimestamp,
+ txTimestamp
);
- expectedReserveData.averageStableBorrowRate = calcExpectedAverageStableBorrowRate(
- reserveDataBeforeAction.averageStableBorrowRate,
- reserveDataBeforeAction.totalStableDebt,
- amountRepaidBN.negated(),
- userDataBeforeAction.stableBorrowRate
+ expectedReserveData.principalStableDebt = expectedReserveData.totalStableDebt = expectedDebt.minus(
+ amountRepaidBN
);
+ //due to accumulation errors, the total stable debt might be smaller than the last user debt.
+ //in this case we simply set the total supply and avg stable rate to 0.
+ if (expectedReserveData.principalStableDebt.lt(0)) {
+ expectedReserveData.principalStableDebt = expectedReserveData.totalStableDebt = new BigNumber(
+ 0
+ );
+ expectedReserveData.averageStableBorrowRate = new BigNumber(0);
+ } else {
+ expectedReserveData.averageStableBorrowRate = calcExpectedAverageStableBorrowRate(
+ reserveDataBeforeAction.averageStableBorrowRate,
+ expectedDebt,
+ amountRepaidBN.negated(),
+ userDataBeforeAction.stableBorrowRate
+ );
+ }
+
expectedReserveData.scaledVariableDebt = reserveDataBeforeAction.scaledVariableDebt;
expectedReserveData.totalVariableDebt = reserveDataBeforeAction.totalVariableDebt;
} else {
@@ -636,22 +686,18 @@ export const calcExpectedUserDataAfterRepay = (
userDataBeforeAction.stableRateLastUpdated,
currentTimestamp
);
-
+
let totalRepaidBN = new BigNumber(totalRepaid);
if (totalRepaidBN.abs().eq(MAX_UINT_AMOUNT)) {
- totalRepaidBN =
- rateMode == RateMode.Stable
- ? stableDebt
- : variableDebt;
+ totalRepaidBN = rateMode == RateMode.Stable ? stableDebt : variableDebt;
}
if (rateMode == RateMode.Stable) {
-
expectedUserData.scaledVariableDebt = userDataBeforeAction.scaledVariableDebt;
expectedUserData.currentVariableDebt = userDataBeforeAction.currentVariableDebt;
expectedUserData.principalStableDebt = expectedUserData.currentStableDebt = stableDebt.minus(
- totalRepaid
+ totalRepaidBN
);
if (expectedUserData.currentStableDebt.eq('0')) {
@@ -664,15 +710,17 @@ export const calcExpectedUserDataAfterRepay = (
expectedUserData.stableRateLastUpdated = txTimestamp;
}
} else {
-
expectedUserData.currentStableDebt = userDataBeforeAction.principalStableDebt;
expectedUserData.principalStableDebt = stableDebt;
expectedUserData.stableBorrowRate = userDataBeforeAction.stableBorrowRate;
expectedUserData.stableRateLastUpdated = userDataBeforeAction.stableRateLastUpdated;
-
- expectedUserData.scaledVariableDebt = userDataBeforeAction.scaledVariableDebt.minus(totalRepaidBN.rayDiv(expectedDataAfterAction.variableBorrowIndex));
- expectedUserData.currentVariableDebt = expectedUserData.scaledVariableDebt.rayMul(expectedDataAfterAction.variableBorrowIndex);
+ expectedUserData.scaledVariableDebt = userDataBeforeAction.scaledVariableDebt.minus(
+ totalRepaidBN.rayDiv(expectedDataAfterAction.variableBorrowIndex)
+ );
+ expectedUserData.currentVariableDebt = expectedUserData.scaledVariableDebt.rayMul(
+ expectedDataAfterAction.variableBorrowIndex
+ );
}
expectedUserData.liquidityRate = expectedDataAfterAction.liquidityRate;
@@ -1028,23 +1076,17 @@ const calcExpectedAverageStableBorrowRate = (
.decimalPlaces(0, BigNumber.ROUND_DOWN);
};
-const calcExpectedVariableDebtUserIndex = (
- reserveDataBeforeAction: ReserveData,
- expectedUserBalanceAfterAction: BigNumber,
- currentTimestamp: BigNumber
-) => {
- if (expectedUserBalanceAfterAction.eq(0)) {
- return new BigNumber(0);
- }
- return calcExpectedReserveNormalizedDebt(reserveDataBeforeAction, currentTimestamp);
-};
-
export const calcExpectedVariableDebtTokenBalance = (
reserveData: ReserveData,
userData: UserReserveData,
currentTimestamp: BigNumber
) => {
- const normalizedDebt = calcExpectedReserveNormalizedDebt(reserveData, currentTimestamp);
+ const normalizedDebt = calcExpectedReserveNormalizedDebt(
+ reserveData.variableBorrowRate,
+ reserveData.variableBorrowIndex,
+ reserveData.lastUpdateTimestamp,
+ currentTimestamp
+ );
const {scaledVariableDebt} = userData;
@@ -1237,11 +1279,11 @@ const calcExpectedReserveNormalizedIncome = (
};
const calcExpectedReserveNormalizedDebt = (
- reserveData: ReserveData,
+ variableBorrowRate: BigNumber,
+ variableBorrowIndex: BigNumber,
+ lastUpdateTimestamp: BigNumber,
currentTimestamp: BigNumber
) => {
- const {variableBorrowRate, variableBorrowIndex, lastUpdateTimestamp} = reserveData;
-
//if utilization rate is 0, nothing to compound
if (variableBorrowRate.eq('0')) {
return variableBorrowIndex;
@@ -1300,14 +1342,19 @@ const calcExpectedVariableBorrowIndex = (reserveData: ReserveData, timestamp: Bi
return cumulatedInterest.rayMul(reserveData.variableBorrowIndex);
};
-const calcExpectedTotalStableDebt = (reserveData: ReserveData, timestamp: BigNumber) => {
+const calcExpectedTotalStableDebt = (
+ principalStableDebt: BigNumber,
+ averageStableBorrowRate: BigNumber,
+ lastUpdateTimestamp: BigNumber,
+ currentTimestamp: BigNumber
+) => {
const cumulatedInterest = calcCompoundedInterest(
- reserveData.averageStableBorrowRate,
- timestamp,
- reserveData.lastUpdateTimestamp
+ averageStableBorrowRate,
+ currentTimestamp,
+ lastUpdateTimestamp
);
- return cumulatedInterest.rayMul(reserveData.principalStableDebt);
+ return cumulatedInterest.rayMul(principalStableDebt);
};
const calcExpectedTotalVariableDebt = (
diff --git a/test/scenario.spec.ts b/test/scenario.spec.ts
index 54fe7433..98e0c164 100644
--- a/test/scenario.spec.ts
+++ b/test/scenario.spec.ts
@@ -10,7 +10,7 @@ import {executeStory} from './helpers/scenario-engine';
const scenarioFolder = './test/helpers/scenarios/';
-const selectedScenarios: string[] = [];
+const selectedScenarios: string[] = ['borrow-repay-variable.json'];
fs.readdirSync(scenarioFolder).forEach((file) => {
if (selectedScenarios.length > 0 && !selectedScenarios.includes(file)) return;