1 files changed, 45 insertions, 0 deletions
diff --git a/src/mongo/db/transaction_participant_test.cpp b/src/mongo/db/transaction_participant_test.cpp
index b2b92ec6892..646431735da 100644
--- a/src/mongo/db/transaction_participant_test.cpp
+++ b/src/mongo/db/transaction_participant_test.cpp
@@ -769,6 +769,51 @@ TEST_F(TxnParticipantTest, ThrowDuringOnTransactionPrepareAbortsTransaction) {
     ASSERT(txnParticipant.transactionIsAborted());
 }
 
+TEST_F(TxnParticipantTest, UnstashFailsShouldLeaveTxnResourceStashUnchanged) {
+    auto sessionCheckout = checkOutSession();
+    auto txnParticipant = TransactionParticipant::get(opCtx());
+
+    txnParticipant.unstashTransactionResources(opCtx(), "prepareTransaction");
+    ASSERT_TRUE(opCtx()->lockState()->isLocked());
+
+    // Simulate the locking of an insert.
+    {
+        Lock::DBLock dbLock(opCtx(), "test", MODE_IX);
+        Lock::CollectionLock collLock(opCtx(), NamespaceString("test.foo"), MODE_IX);
+    }
+
+    auto prepareTimestamp = txnParticipant.prepareTransaction(opCtx(), {});
+
+    // Simulate a secondary style lock stashing such that the locks are yielded.
+    {
+        repl::UnreplicatedWritesBlock uwb(opCtx());
+        opCtx()->lockState()->unsetMaxLockTimeout();
+        txnParticipant.stashTransactionResources(opCtx());
+    }
+    ASSERT_FALSE(txnParticipant.getTxnResourceStashLockerForTest()->isLocked());
+
+    // Enable fail point.
+    getGlobalFailPointRegistry()->getFailPoint("restoreLocksFail")->setMode(FailPoint::alwaysOn);
+
+    ASSERT_THROWS_CODE(txnParticipant.unstashTransactionResources(opCtx(), "commitTransaction"),
+                       AssertionException,
+                       ErrorCodes::LockTimeout);
+
+    // Above unstash attempt fail should leave the txnResourceStash unchanged.
+    ASSERT_FALSE(txnParticipant.getTxnResourceStashLockerForTest()->isLocked());
+
+    // Disable fail point.
+    getGlobalFailPointRegistry()->getFailPoint("restoreLocksFail")->setMode(FailPoint::off);
+
+    // Should be successfully able to perform lock restore.
+    txnParticipant.unstashTransactionResources(opCtx(), "commitTransaction");
+    ASSERT_TRUE(opCtx()->lockState()->isLocked());
+
+    // Commit the transaction to release the locks.
+    txnParticipant.commitPreparedTransaction(opCtx(), prepareTimestamp, boost::none);
+    ASSERT_TRUE(txnParticipant.transactionIsCommitted());
+}
+
 TEST_F(TxnParticipantTest, StepDownAfterPrepareDoesNotBlock) {
     auto sessionCheckout = checkOutSession();
     auto txnParticipant = TransactionParticipant::get(opCtx());