✨ escrow: mint to recipient onStreamCanceled hook

.gas-snapshot

@@ -93,33 +93,35 @@ DebtPreviewerTest:testPreviewLeverageSameWETHAssetMaxRatioMultipleCollateralAndD
 DebtPreviewerTest:testPreviewLeverageSameWETHAssetMultipleCollateralAndDebtWithMinHealthFactor() (gas: 1708472)
 DebtPreviewerTest:testPreviewMaxRatioWithdrawWithSameAssetLeverage() (gas: 1020516)
 DebtPreviewerTest:testPreviewSameAssetInvalidLeverageShouldCapRatio() (gas: 910754)
-EscrowedEXATest:testCancelShouldDeleteReserves() (gas: 470835)
-EscrowedEXATest:testCancelShouldGiveReservesBack() (gas: 676167)
-EscrowedEXATest:testCancelTwiceShouldRevert() (gas: 470405)
-EscrowedEXATest:testCancelWithInvalidAccount() (gas: 348063)
-EscrowedEXATest:testGrantTransferrerRoleAsAdmin() (gas: 45857)
-EscrowedEXATest:testMint() (gas: 165097)
-EscrowedEXATest:testMintMoreThanBalance() (gas: 27542)
-EscrowedEXATest:testMintToAnother() (gas: 167315)
-EscrowedEXATest:testMintZero() (gas: 14141)
-EscrowedEXATest:testRedeemAsNotRedeemer() (gas: 214597)
-EscrowedEXATest:testRedeemAsRedeemer() (gas: 165462)
-EscrowedEXATest:testRedeemAsRedeemerToAnother() (gas: 170346)
+EscrowedEXATest:testCancelFromStreamAndGetReserveBack() (gas: 457085)
+EscrowedEXATest:testCancelFromStreamJustCreated() (gas: 412309)
+EscrowedEXATest:testCancelShouldDeleteReserves() (gas: 470857)
+EscrowedEXATest:testCancelShouldGiveReservesBack() (gas: 676123)
+EscrowedEXATest:testCancelTwiceShouldRevert() (gas: 470361)
+EscrowedEXATest:testCancelWithInvalidAccount() (gas: 348019)
+EscrowedEXATest:testGrantTransferrerRoleAsAdmin() (gas: 45901)
+EscrowedEXATest:testMint() (gas: 165141)
+EscrowedEXATest:testMintMoreThanBalance() (gas: 27564)
+EscrowedEXATest:testMintToAnother() (gas: 167337)
+EscrowedEXATest:testMintZero() (gas: 14163)
+EscrowedEXATest:testRedeemAsNotRedeemer() (gas: 214641)
+EscrowedEXATest:testRedeemAsRedeemer() (gas: 165497)
+EscrowedEXATest:testRedeemAsRedeemerToAnother() (gas: 170381)
 EscrowedEXATest:testSetReserveRatioAsAdmin() (gas: 24450)
-EscrowedEXATest:testSetReserveRatioAsNotAdmin() (gas: 47296)
-EscrowedEXATest:testSetVestingPeriodAsAdmin() (gas: 24707)
-EscrowedEXATest:testSetVestingPeriodAsNotAdmin() (gas: 47520)
-EscrowedEXATest:testTransferToNotTransferrer() (gas: 174731)
-EscrowedEXATest:testTransferToTransferrer() (gas: 210331)
-EscrowedEXATest:testVest() (gas: 347009)
+EscrowedEXATest:testSetReserveRatioAsNotAdmin() (gas: 47318)
+EscrowedEXATest:testSetVestingPeriodAsAdmin() (gas: 24598)
+EscrowedEXATest:testSetVestingPeriodAsNotAdmin() (gas: 47411)
+EscrowedEXATest:testTransferToNotTransferrer() (gas: 174775)
+EscrowedEXATest:testTransferToTransferrer() (gas: 210353)
+EscrowedEXATest:testVest() (gas: 346856)
 EscrowedEXATest:testVestToAnother() (gas: 403671)
-EscrowedEXATest:testVestToAnotherAndCancel() (gas: 489382)
-EscrowedEXATest:testVestWithPermitReserve() (gas: 458530)
-EscrowedEXATest:testVestZero() (gas: 14239)
-EscrowedEXATest:testWithdrawFromStreamAndGetReserveBack() (gas: 329574)
-EscrowedEXATest:testWithdrawMaxFromMultipleStreams() (gas: 1006869)
-EscrowedEXATest:testWithdrawMaxShouldGiveReserveBackWhenDepleted() (gas: 327564)
-EscrowedEXATest:testWithdrawMaxWithInvalidSender() (gas: 339458)
+EscrowedEXATest:testVestToAnotherAndCancel() (gas: 489338)
+EscrowedEXATest:testVestWithPermitReserve() (gas: 458552)
+EscrowedEXATest:testVestZero() (gas: 14151)
+EscrowedEXATest:testWithdrawFromStreamAndGetReserveBack() (gas: 329552)
+EscrowedEXATest:testWithdrawMaxFromMultipleStreams() (gas: 1006649)
+EscrowedEXATest:testWithdrawMaxShouldGiveReserveBackWhenDepleted() (gas: 327542)
+EscrowedEXATest:testWithdrawMaxWithInvalidSender() (gas: 339414)
 InterestRateModelTest:testFixedBorrowRate() (gas: 8089)
 InterestRateModelTest:testFloatingBorrowRate() (gas: 6236)
 InterestRateModelTest:testMinFixedRate() (gas: 7610)

contracts/periphery/EscrowedEXA.sol

@@ -162,6 +162,15 @@ contract EscrowedEXA is ERC20VotesUpgradeable, AccessControlUpgradeable {
     }
   }
 
+  /// @notice Hook called when a recipient cancels a stream.
+  /// @notice Mints esEXA to the recipient with the remaining EXA received from the canceled stream.
+  /// @param recipient recipient of the cancelled stream.
+  /// @param senderAmount amount of EXA sent to the recipient.
+  function onStreamCanceled(uint256, address recipient, uint128 senderAmount, uint128) external {
+    assert(msg.sender == address(sablier));
+    _mint(recipient, senderAmount);
+  }
+
   /// @notice Sets the vesting period.
   /// @param vestingPeriod_ New vesting period.
   /// @dev Caller must have DEFAULT_ADMIN_ROLE.

test/EscrowedEXA.t.sol

@@ -407,6 +407,41 @@ contract EscrowedEXATest is ForkTest {
     assertEq(exa.balanceOf(address(this)), exaBefore + amount + reserve, "got amount + reserve back");
   }
 
+  function testCancelFromStreamAndGetReserveBack() external {
+    uint256 amount = 1_000 ether;
+    uint256 reserve = amount.mulWadDown(esEXA.reserveRatio());
+    esEXA.mint(amount, address(this));
+    uint256[] memory streams = new uint256[](1);
+    streams[0] = esEXA.vest(uint128(amount), address(this));
+
+    uint256 exaBefore = exa.balanceOf(address(this));
+    vm.warp(block.timestamp + esEXA.vestingPeriod() / 2);
+
+    esEXA.sablier().cancel(streams[0]);
+
+    assertEq(esEXA.balanceOf(address(this)), amount / 2, "half esEXA sholud be back");
+
+    esEXA.withdrawMax(streams);
+    assertEq(exa.balanceOf(address(this)), exaBefore + amount / 2 + reserve, "amount/2 + reserve should be back");
+  }
+
+  function testCancelFromStreamJustCreated() external {
+    uint256 amount = 1_000 ether;
+    uint256 reserve = amount.mulWadDown(esEXA.reserveRatio());
+    esEXA.mint(amount, address(this));
+    uint256[] memory streams = new uint256[](1);
+    streams[0] = esEXA.vest(uint128(amount), address(this));
+
+    uint256 exaBefore = exa.balanceOf(address(this));
+
+    esEXA.sablier().cancel(streams[0]);
+
+    assertEq(esEXA.balanceOf(address(this)), amount, "amount esEXA sholud be back");
+
+    esEXA.withdrawMax(streams);
+    assertEq(exa.balanceOf(address(this)), exaBefore + reserve, "reserve should be back");
+  }
+
   event ReserveRatioSet(uint256 reserveRatio);
   event VestingPeriodSet(uint256 vestingPeriod);
   event Vest(address indexed caller, address indexed account, uint256 indexed streamId, uint256 amount);