🚸 escrow: return reserve on external stream cancel

Co-authored-by: danilo neves cruz <cruzdanilo@gmail.com>

.changeset/thin-bugs-do.md

@@ -0,0 +1,5 @@
+---
+"@exactly/protocol": patch
+---
+
+🚸 escrow: return reserve on external stream cancel

.gas-snapshot

@@ -95,8 +95,8 @@ DebtPreviewerTest:testPreviewMaxRatioWithdrawWithSameAssetLeverage() (gas: 10205
 DebtPreviewerTest:testPreviewSameAssetInvalidLeverageShouldCapRatio() (gas: 910754)
 EscrowedEXATest:testCancelExternalStreams() (gas: 452302)
 EscrowedEXATest:testCancelExternalStreamsWithesEXACancel() (gas: 903873)
-EscrowedEXATest:testCancelFromStreamAndGetReserveBack() (gas: 457589)
-EscrowedEXATest:testCancelFromStreamJustCreated() (gas: 412791)
+EscrowedEXATest:testCancelFromStreamAndGetReserveBack() (gas: 451714)
+EscrowedEXATest:testCancelFromStreamJustCreated() (gas: 404796)
 EscrowedEXATest:testCancelShouldDeleteReserves() (gas: 471143)
 EscrowedEXATest:testCancelShouldGiveReservesBack() (gas: 676562)
 EscrowedEXATest:testCancelTwiceShouldRevert() (gas: 456028)
@@ -122,10 +122,10 @@ EscrowedEXATest:testVestToAnother() (gas: 403826)
 EscrowedEXATest:testVestToAnotherAndCancel() (gas: 489580)
 EscrowedEXATest:testVestWithPermitReserve() (gas: 458876)
 EscrowedEXATest:testVestZero() (gas: 14151)
-EscrowedEXATest:testWithdrawFromStreamAndGetReserveBack() (gas: 329816)
+EscrowedEXATest:testWithdrawFromStreamAndGetReserveBack() (gas: 329850)
 EscrowedEXATest:testWithdrawFromUnknownStream() (gas: 898481)
 EscrowedEXATest:testWithdrawMaxFromMultipleStreams() (gas: 1007617)
-EscrowedEXATest:testWithdrawMaxShouldGiveReserveBackWhenDepleted() (gas: 327828)
+EscrowedEXATest:testWithdrawMaxShouldGiveReserveBackWhenDepleted() (gas: 327862)
 EscrowedEXATest:testWithdrawMaxWithInvalidSender() (gas: 339700)
 InterestRateModelTest:testFixedBorrowRate() (gas: 8089)
 InterestRateModelTest:testFloatingBorrowRate() (gas: 6236)

contracts/periphery/EscrowedEXA.sol

@@ -157,11 +157,7 @@ contract EscrowedEXA is ERC20VotesUpgradeable, AccessControlUpgradeable {
   /// @param streamId streamId to withdraw from.
   function withdrawMax(uint256 streamId) internal {
     if (sablier.withdrawableAmountOf(streamId) != 0) sablier.withdrawMax(streamId, msg.sender);
-    if (sablier.isDepleted(streamId)) {
-      uint256 reserve = reserves[streamId];
-      delete reserves[streamId];
-      exa.safeTransfer(msg.sender, reserve);
-    }
+    if (sablier.isDepleted(streamId)) returnReserve(streamId, msg.sender);
   }
 
   /// @notice Checks if a stream is valid through its reserve. Reverts with `InvalidStream` if it is not.
@@ -170,6 +166,15 @@ contract EscrowedEXA is ERC20VotesUpgradeable, AccessControlUpgradeable {
     if (reserves[streamId] == 0) revert InvalidStream();
   }
 
+  /// @notice Returns the reserve to the recipient.
+  /// @param streamId streamId of the reserve to return.
+  /// @param recipient recipient of the reserve.
+  function returnReserve(uint256 streamId, address recipient) internal {
+    uint256 reserve = reserves[streamId];
+    delete reserves[streamId];
+    exa.safeTransfer(recipient, reserve);
+  }
+
   /// @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 streamId streamId of the cancelled stream.
@@ -179,6 +184,7 @@ contract EscrowedEXA is ERC20VotesUpgradeable, AccessControlUpgradeable {
     assert(msg.sender == address(sablier));
     checkStream(streamId);
     _mint(recipient, senderAmount);
+    returnReserve(streamId, recipient);
   }
 
   /// @notice Sets the vesting period.

test/EscrowedEXA.t.sol

@@ -416,18 +416,17 @@ contract EscrowedEXATest is ForkTest {
     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 streamId = 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.sablier().cancel(streamId);
 
-    esEXA.withdrawMax(streams);
-    assertEq(exa.balanceOf(address(this)), exaBefore + amount / 2 + reserve, "amount/2 + reserve should be back");
+    assertEq(esEXA.balanceOf(address(this)), amount / 2, "half esEXA should be back");
+    assertEq(exa.balanceOf(address(this)), exaBefore + reserve, "reserve should be back");
+    esEXA.sablier().withdrawMax(streamId, address(this));
+    assertEq(exa.balanceOf(address(this)), exaBefore + reserve + amount / 2, "amount/2 should be back");
   }
 
   function testCancelFromStreamJustCreated() external {
@@ -441,9 +440,7 @@ contract EscrowedEXATest is ForkTest {
 
     esEXA.sablier().cancel(streams[0]);
 
-    assertEq(esEXA.balanceOf(address(this)), amount, "amount esEXA sholud be back");
-
-    esEXA.withdrawMax(streams);
+    assertEq(esEXA.balanceOf(address(this)), amount, "amount esEXA should be back");
     assertEq(exa.balanceOf(address(this)), exaBefore + reserve, "reserve should be back");
   }