fix: VPB-03 maximum should depend on chain and whether the contracts …

…are time or block-based

contracts/VToken.sol

@@ -53,6 +53,13 @@ contract VToken is
 
     uint256 internal constant DEFAULT_PROTOCOL_SEIZE_SHARE_MANTISSA = 5e16; // 5%
 
+    // Maximum fraction of interest that can be set aside for reserves
+    uint256 internal constant MAX_RESERVE_FACTOR_MANTISSA = 1e18;
+
+    // Maximum borrow rate that can ever be applied (.0005% / slot(block or second))
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable
+    uint256 internal immutable MAX_BORROW_RATE_MANTISSA;
+
     /**
      * Reentrancy Guard **
      */
@@ -72,9 +79,14 @@ contract VToken is
      * @param blocksPerYear_ The number of blocks per year
      * @custom:oz-upgrades-unsafe-allow constructor
      */
-    constructor(bool timeBased_, uint256 blocksPerYear_) TimeManagerV8(timeBased_, blocksPerYear_) {
+    constructor(
+        bool timeBased_,
+        uint256 blocksPerYear_,
+        uint256 maxBorrowRateMantissa_
+    ) TimeManagerV8(timeBased_, blocksPerYear_) {
         // Note that the contract is upgradeable. Use initialize() or reinitializers
         // to set the state variables.
+        MAX_BORROW_RATE_MANTISSA = maxBorrowRateMantissa_;
         _disableInitializers();
     }
 

contracts/VTokenInterfaces.sol

@@ -54,12 +54,6 @@ contract VTokenStorage {
      */
     address payable public protocolShareReserve;
 
-    // Maximum borrow rate that can ever be applied (.0005% / slot(block or second))
-    uint256 internal constant MAX_BORROW_RATE_MANTISSA = 0.0005e16;
-
-    // Maximum fraction of interest that can be set aside for reserves
-    uint256 internal constant MAX_RESERVE_FACTOR_MANTISSA = 1e18;
-
     /**
      * @notice Contract which oversees inter-vToken operations
      */

contracts/test/UpgradedVToken.sol

@@ -18,7 +18,11 @@ contract UpgradedVToken is VToken {
      * @param blocksPerYear_ The number of blocks per year
      * @custom:oz-upgrades-unsafe-allow constructor
      */
-    constructor(bool timeBased_, uint256 blocksPerYear_) VToken(timeBased_, blocksPerYear_) {
+    constructor(
+        bool timeBased_,
+        uint256 blocksPerYear_,
+        uint256 maxBorrowRateMantissa_
+    ) VToken(timeBased_, blocksPerYear_, maxBorrowRateMantissa_) {
         // Note that the contract is upgradeable. Use initialize() or reinitializers
         // to set the state variables.
         _disableInitializers();

contracts/test/VTokenHarness.sol

@@ -18,7 +18,11 @@ contract VTokenHarness is VToken {
      * @param blocksPerYear_ The number of blocks per year
      * @custom:oz-upgrades-unsafe-allow constructor
      */
-    constructor(bool timeBased_, uint256 blocksPerYear_) VToken(timeBased_, blocksPerYear_) {
+    constructor(
+        bool timeBased_,
+        uint256 blocksPerYear_,
+        uint256 maxBorrowRateMantissa_
+    ) VToken(timeBased_, blocksPerYear_, maxBorrowRateMantissa_) {
         // Note that the contract is upgradeable. Use initialize() or reinitializers
         // to set the state variables.
         _disableInitializers();
@@ -118,7 +122,7 @@ contract VTokenHarness is VToken {
         return (snapshot.principal, snapshot.interestIndex);
     }
 
-    function getBorrowRateMaxMantissa() external pure returns (uint256) {
+    function getBorrowRateMaxMantissa() external view returns (uint256) {
         return MAX_BORROW_RATE_MANTISSA;
     }
 

deploy/009-deploy-vtokens.ts

@@ -21,6 +21,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   const { tokensConfig, poolConfig, preconfiguredAddresses } = await getConfig(hre.network.name);
 
   const { isTimeBased, blocksPerYear } = getBlockOrTimestampBasedDeploymentInfo(hre.network.name);
+  const maxBorrowRateMantissa = BigNumber.from(0.0005e16);
 
   const accessControlManagerAddress = await toAddress(
     preconfiguredAddresses.AccessControlManager || "AccessControlManager",
@@ -31,7 +32,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   const vTokenImpl: DeployResult = await deploy("VTokenImpl", {
     contract: "VToken",
     from: deployer,
-    args: [isTimeBased, blocksPerYear],
+    args: [isTimeBased, blocksPerYear, maxBorrowRateMantissa],
     log: true,
     autoMine: true,
   });

deploy/016-deploy-beacon-implementations.ts

@@ -13,6 +13,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   const { isTimeBased, blocksPerYear } = getBlockOrTimestampBasedDeploymentInfo(hre.network.name);
 
   const poolRegistry = await ethers.getContract("PoolRegistry");
+  const maxBorrowRateMantissa = ethers.BigNumber.from(0.0005e16);
 
   // Comptroller Implementation
   await deploy("ComptrollerImpl", {
@@ -27,7 +28,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   await deploy("VTokenImpl", {
     contract: "VToken",
     from: deployer,
-    args: [isTimeBased, blocksPerYear],
+    args: [isTimeBased, blocksPerYear, maxBorrowRateMantissa],
     log: true,
     autoMine: true,
   });

tests/hardhat/Rewards.ts

@@ -63,6 +63,8 @@ async function rewardsFixture(isTimeBased: boolean) {
   const btcPrice = "21000.34";
   const daiPrice = "1";
 
+  const maxBorrowRateMantissa = ethers.BigNumber.from(0.0005e16);
+
   fakePriceOracle.getUnderlyingPrice.returns((args: any) => {
     if (vDAI && vWBTC) {
       if (args[0] === vDAI.address) {
@@ -104,7 +106,7 @@ async function rewardsFixture(isTimeBased: boolean) {
 
   // Deploy VTokens
   const RewardsDistributor = await ethers.getContractFactory("RewardsDistributor");
-  const vTokenBeacon = await deployVTokenBeacon(undefined, isTimeBased, blocksPerYear);
+  const vTokenBeacon = await deployVTokenBeacon(undefined, maxBorrowRateMantissa, isTimeBased, blocksPerYear);
   vWBTC = await makeVToken({
     underlying: mockWBTC,
     comptroller: comptrollerProxy,

tests/hardhat/Shortfall.ts

@@ -62,6 +62,8 @@ async function shortfallFixture() {
   mockBUSD = await MockBUSD.deploy("BUSD", "BUSD", 18);
   await mockBUSD.faucet(convertToUnit(100000, 18));
 
+  const maxBorrowRateMantissa = ethers.BigNumber.from(0.0005e16);
+
   const AccessControlManagerFactor = await ethers.getContractFactory("AccessControlManager");
   accessControlManager = await AccessControlManagerFactor.deploy();
   fakeRiskFund = await smock.fake<IRiskFund>("IRiskFund");
@@ -104,9 +106,9 @@ async function shortfallFixture() {
   });
 
   const VToken = await smock.mock<VToken__factory>("VToken");
-  vDAI = await VToken.deploy(isTimeBased, blocksPerYear);
-  vWBTC = await VToken.deploy(isTimeBased, blocksPerYear);
-  vFloki = await VToken.deploy(isTimeBased, blocksPerYear);
+  vDAI = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
+  vWBTC = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
+  vFloki = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
 
   await vWBTC.setVariable("decimals", 8);
   vDAI.decimals.returns(18);
@@ -189,6 +191,8 @@ async function timeBasedhortfallFixture() {
   waitForFirstBidder = 300;
   nextBidderBlockOrTimestampLimit = 300;
 
+  const maxBorrowRateMantissa = ethers.BigNumber.from(0.0005e16);
+
   const MockBUSD = await ethers.getContractFactory("MockToken");
   mockBUSD = await MockBUSD.deploy("BUSD", "BUSD", 18);
   await mockBUSD.faucet(convertToUnit(100000, 18));
@@ -236,9 +240,9 @@ async function timeBasedhortfallFixture() {
   });
 
   const VToken = await smock.mock<VToken__factory>("VToken");
-  vDAI = await VToken.deploy(isTimeBased, blocksPerYear);
-  vWBTC = await VToken.deploy(isTimeBased, blocksPerYear);
-  vFloki = await VToken.deploy(isTimeBased, blocksPerYear);
+  vDAI = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
+  vWBTC = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
+  vFloki = await VToken.deploy(isTimeBased, blocksPerYear, maxBorrowRateMantissa);
 
   await vWBTC.setVariable("decimals", 8);
   vDAI.decimals.returns(18);

tests/hardhat/UpgradedVToken.ts

@@ -106,8 +106,10 @@ for (const isTimeBased of [false, true]) {
     });
 
     it("Upgrade the vToken contract", async function () {
+      const maxBorrowRateMantissa = ethers.BigNumber.from(0.0005e16);
+
       const vToken = await ethers.getContractFactory("UpgradedVToken");
-      const vTokenDeploy = await vToken.deploy(isTimeBased, slotsPerYear);
+      const vTokenDeploy = await vToken.deploy(isTimeBased, slotsPerYear, maxBorrowRateMantissa);
 
       await vTokenDeploy.deployed();
 

tests/hardhat/util/TokenTestHelpers.ts

@@ -37,6 +37,7 @@ interface VTokenParameters {
   beacon: UpgradeableBeacon;
   isTimeBased: boolean;
   blocksPerYear: BigNumberish;
+  maxBorrowRateMantissa: BigNumberish;
 }
 
 const getNameAndSymbol = async (underlying: AddressOrContract): Promise<[string, string]> => {
@@ -74,12 +75,13 @@ export type AnyVTokenFactory = VTokenHarness__factory | VToken__factory;
 
 export const deployVTokenBeacon = async <VTokenFactory extends AnyVTokenFactory = VToken__factory>(
   { kind }: { kind: string } = { kind: "VToken" },
+  maxBorrowRateMantissa: BigNumberish = BigNumber.from(0.0005e16),
   isTimeBased: boolean = false,
   blocksPerYear: BigNumberish = BSC_BLOCKS_PER_YEAR,
 ): Promise<UpgradeableBeacon> => {
   const VToken = await ethers.getContractFactory<VTokenFactory>(kind);
   const vTokenBeacon = (await upgrades.deployBeacon(VToken, {
-    constructorArgs: [isTimeBased, blocksPerYear],
+    constructorArgs: [isTimeBased, blocksPerYear, maxBorrowRateMantissa],
   })) as UpgradeableBeacon;
   return vTokenBeacon;
 };
@@ -106,10 +108,12 @@ const deployVTokenDependencies = async <VTokenFactory extends AnyVTokenFactory =
     shortfall: params.shortfall || (await smock.fake("Shortfall")),
     protocolShareReserve: params.protocolShareReserve || (await smock.fake("ProtocolShareReserve")),
     reserveFactorMantissa: params.reserveFactorMantissa || parseUnits("0.3", 18),
+    maxBorrowRateMantissa: params.maxBorrowRateMantissa || BigNumber.from(0.0005e16),
     beacon:
       params.beacon ||
       (await deployVTokenBeacon<VTokenFactory>(
         { kind },
+        params.maxBorrowRateMantissa || BigNumber.from(0.0005e16),
         params.isTimeBased || false,
         params.blocksPerYear === undefined ? BSC_BLOCKS_PER_YEAR : params.blocksPerYear,
       )),