From f90e0e0731808e07293f601a222986b775f5de02 Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Sep 2024 09:49:41 -0400
Subject: [PATCH] make future withdrawals unimpacted by previous cancellations
 (#1194)

---
 contracts/p0/StRSR.sol |  3 +--
 contracts/p1/StRSR.sol |  4 +++-
 test/ZZStRSR.test.ts   | 43 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/contracts/p0/StRSR.sol b/contracts/p0/StRSR.sol
index 814a4a94e7..4a3c0a1da9 100644
--- a/contracts/p0/StRSR.sol
+++ b/contracts/p0/StRSR.sol
@@ -272,8 +272,7 @@ contract StRSRP0 is IStRSR, ComponentP0, EIP712Upgradeable {
         uint256 i = start;
         for (; i < endId; i++) {
             total += queue[i].rsrAmount;
-            queue[i].rsrAmount = 0;
-            queue[i].stakeAmount = 0;
+            delete queue[i];
         }
 
         // Execute accumulated withdrawals
diff --git a/contracts/p1/StRSR.sol b/contracts/p1/StRSR.sol
index 5a6c001229..6e7b1e6f55 100644
--- a/contracts/p1/StRSR.sol
+++ b/contracts/p1/StRSR.sol
@@ -654,7 +654,9 @@ abstract contract StRSRP1 is Initializable, ComponentP1, IStRSR, EIP712Upgradeab
         index = queue.length;
 
         uint192 oldDrafts = index != 0 ? queue[index - 1].drafts : 0;
-        uint64 lastAvailableAt = index != 0 ? queue[index - 1].availableAt : 0;
+        uint64 lastAvailableAt = index != 0 && firstRemainingDraft[draftEra][account] < index
+            ? queue[index - 1].availableAt
+            : 0;
         availableAt = uint64(block.timestamp) + unstakingDelay;
         if (lastAvailableAt > availableAt) {
             availableAt = lastAvailableAt;
diff --git a/test/ZZStRSR.test.ts b/test/ZZStRSR.test.ts
index 6fbcd2b3d4..06fba12cc2 100644
--- a/test/ZZStRSR.test.ts
+++ b/test/ZZStRSR.test.ts
@@ -552,6 +552,49 @@ describe(`StRSRP${IMPLEMENTATION} contract`, () => {
         .withArgs(0, 2, addr1.address, amount.div(2), amount, anyValue)
     })
 
+    it('Should not impact future withdrawals after cancellation -- regression test 9/04/2024', async () => {
+      // Context: https://github.com/code-423n4/2024-07-reserve-findings/issues/18
+
+      // old unstakingDelay is 1 day
+      const oldUnstakingDelay = 3600 * 24
+      await stRSR.connect(owner).setUnstakingDelay(oldUnstakingDelay)
+      const amount: BigNumber = bn('100e18')
+      await rsr.connect(addr1).approve(stRSR.address, amount)
+      await stRSR.connect(addr1).stake(amount)
+
+      const draftEra = 1
+      const availableAtOfFirst = (await getLatestBlockTimestamp()) + oldUnstakingDelay + 1
+      /**
+       * Unstaking request enter a queue, and withdrawal become available 1 day later
+       */
+      await expect(stRSR.connect(addr1).unstake(amount))
+        .emit(stRSR, 'UnstakingStarted')
+        .withArgs(0, draftEra, addr1.address, amount, amount, availableAtOfFirst)
+
+      /**
+       * Cancel the unstaking to eliminate any pending withdrawals
+       */
+      await stRSR.connect(addr1).cancelUnstake(1)
+
+      // new unstakingDelay is 1 hour
+      const newUnstakingDelay = 3600
+      await stRSR.connect(owner).setUnstakingDelay(newUnstakingDelay)
+
+      await rsr.connect(addr2).approve(stRSR.address, amount)
+      await stRSR.connect(addr2).stake(amount)
+
+      const availableAtOfFirstOfUser2 = (await getLatestBlockTimestamp()) + newUnstakingDelay + 1
+      /**
+       * Unstaking request enter a queue. Withdrawal should become available 1 hour later for both users
+       */
+      await expect(stRSR.connect(addr2).unstake(amount))
+        .emit(stRSR, 'UnstakingStarted')
+        .withArgs(0, draftEra, addr2.address, amount, amount, availableAtOfFirstOfUser2)
+      await expect(stRSR.connect(addr1).unstake(amount))
+        .emit(stRSR, 'UnstakingStarted')
+        .withArgs(1, draftEra, addr1.address, amount, amount, availableAtOfFirstOfUser2 + 1)
+    })
+
     it('Should create Pending withdrawal when unstaking', async () => {
       const amount: BigNumber = bn('1000e18')