fix(CFv1): skip revocation of already repaid loans on credit lines

contracts/capybara-finance/CHANGELOG.md

@@ -1,4 +1,15 @@
-# Unreleased
+# v1.24.0
+
+## Main Changes
+
+Fixed the `_revokeLoan()` internal function to skip the `onAfterLoanRevocation()` credit line hook for already repaid loans (where `trackedBalance == 0`). Previously, revoking an installment loan that contained fully repaid sub-loans would still call the credit line hook for those sub-loans, incorrectly decrementing the borrower's `activeLoanCount` and `totalActiveLoanAmount` in the credit line state. Now the hook is only called for sub-loans that have an outstanding balance at the time of revocation.
+
+## Migration
+
+1. No special actions required, just upgrade the deployed `CapybaraFinance` smart-contracts.
+2. To be sure there are no broken borrower states on existing credit lines, you can check all the cases of loan revocation through the block explorer database. Only installment loan revocation cases should be checked through event `InstallmentLoanRevoked` because fully repaid ordinary loans cannot be revoked. The installment loans with a single installment can be skipped as well.
+
+# v1.23.1
 
 ## Main Changes
 

contracts/capybara-finance/contracts/LendingMarket.sol

@@ -774,11 +774,14 @@ contract LendingMarket is
      */
     function _revokeLoan(uint256 loanId, Loan.State storage loan) internal {
         address creditLine = _programCreditLines[loan.programId];
+        bool isLoanRepaid = _isRepaid(loan);
 
         loan.trackedBalance = 0;
         loan.trackedTimestamp = _blockTimestamp().toUint32();
 
-        ICreditLine(creditLine).onAfterLoanRevocation(loanId);
+        if (!isLoanRepaid) {
+            ICreditLine(creditLine).onAfterLoanRevocation(loanId);
+        }
 
         emit LoanRevoked(loanId);
     }

contracts/capybara-finance/contracts/Versionable.sol

@@ -12,6 +12,6 @@ import { IVersionable } from "@cloudwalk/brlc-base/interfaces/IVersionable.sol";
 abstract contract Versionable is IVersionable {
     /// @inheritdoc IVersionable
     function $__VERSION() external pure returns (Version memory) {
-        return Version(1, 23, 0);
+        return Version(1, 24, 0);
     }
 }

contracts/capybara-finance/test-utils/specific.ts

@@ -8,6 +8,6 @@ export interface Version {
 
 export const EXPECTED_VERSION: Version = {
   major: 1,
-  minor: 23,
+  minor: 24,
   patch: 0,
 };

contracts/capybara-finance/test/LendingMarket.base.test.ts

@@ -4741,6 +4741,8 @@ describe("Contract 'LendingMarket': base tests", () => {
       const { market, installmentLoanParts: loans } = fixture;
       const loanIds = loans.map(loan => loan.id);
       const expectedLoans = props.loans.map(loan => clone(loan));
+      const loanRepaidStatesBeforeRevocation = expectedLoans.map(loan => loan.state.trackedBalance == 0);
+      const areAllLoansRepaidBeforeRevocation = loanRepaidStatesBeforeRevocation.every(isRepaid => isRepaid);
       const borrowerBalanceChange = expectedLoans
         .map(loan => loan.state.repaidAmount - loan.state.borrowedAmount)
         .reduce((sum, amount) => sum + amount);
@@ -4756,19 +4758,23 @@ describe("Contract 'LendingMarket': base tests", () => {
 
       const revocationTimestamp = calculateTimestampWithOffset(await getTxTimestamp(tx));
       const actualLoanStates = await getLoanStates(market, loanIds);
-      expectedLoans.forEach((loan) => {
-        loan.state.trackedBalance = 0;
-        loan.state.trackedTimestamp = revocationTimestamp;
-      });
 
       for (let i = 0; i < loanIds.length; ++i) {
         const loanId = loanIds[i];
-        await expect(tx).to.emit(market, EVENT_NAME_LOAN_REVOKED).withArgs(loanId);
+        const loan = expectedLoans[i];
+        loan.state.trackedBalance = 0;
+        loan.state.trackedTimestamp = revocationTimestamp;
         checkEquality(actualLoanStates[i], expectedLoans[i].state, i);
+        await expect(tx).to.emit(market, EVENT_NAME_LOAN_REVOKED).withArgs(loanId);
         // Check hook calls
-        await expect(tx).to.emit(creditLine, EVENT_NAME_ON_AFTER_LOAN_REVOCATION_CALLED).withArgs(loanId);
+        if (!loanRepaidStatesBeforeRevocation[i]) {
+          await expect(tx).to.emit(creditLine, EVENT_NAME_ON_AFTER_LOAN_REVOCATION_CALLED).withArgs(loanId);
+        }
       }
       await expect(tx).to.emit(market, EVENT_NAME_INSTALLMENT_LOAN_REVOKED).withArgs(loanIds[0], loanIds.length);
+      if (areAllLoansRepaidBeforeRevocation) {
+        await expect(tx).not.to.emit(creditLine, EVENT_NAME_ON_AFTER_LOAN_REVOCATION_CALLED);
+      }
 
       const totalAddonAmount = expectedLoans
         .map(loan => loan.state.addonAmount)

contracts/capybara-finance/test/LendingMarket.complex.test.ts

@@ -524,7 +524,7 @@ describe("Contract 'LendingMarket': complex tests", () => {
   }
 
   async function executeAndCheckLoanRevocationForScenario(context: TestScenarioContext) {
-    const { token, lendingMarket, liquidityPool } = context.fixture as Fixture;
+    const { token, lendingMarket, liquidityPool, creditLine } = context.fixture as Fixture;
     const scenario = context.scenario;
     const loanState = await lendingMarket.getLoanState(context.loanId);
     const refundAmount = Number(loanState.repaidAmount) - scenario.borrowedAmount;
@@ -541,9 +541,12 @@ describe("Contract 'LendingMarket': complex tests", () => {
     );
 
     const liquidityPoolBalancesAfter = await liquidityPool.getBalances();
+    const borrowerStateAfter = await creditLine.getBorrowerState(borrower.address);
     expect(liquidityPoolBalancesAfter[0])
       .to.eq(Number(liquidityPoolBalancesBefore[0]) - refundAmount + scenario.addonAmount);
     expect(liquidityPoolBalancesAfter[1]).to.eq(0); // The addonsBalance must be zero because addonTreasury != 0
+    expect(borrowerStateAfter.activeLoanCount).to.eq(0);
+    expect(borrowerStateAfter.totalActiveLoanAmount).to.eq(0);
 
     await checkLoanRepaidAmountForScenario(context);
     await checkLoanClosedState(lendingMarket, context.loanId);