SERVER-36746 Don't erroneously skip drain mode if a stepdown attempt fails.

1 files changed, 61 insertions, 0 deletions

diff --git a/src/mongo/db/repl/replication_coordinator_impl_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
index 1f12e006783..24202d1de02 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
@@ -1668,6 +1668,67 @@ TEST_F(StepDownTest, StepDownCanCompleteBasedOnReplSetUpdatePositionAlone) {
     ASSERT_TRUE(repl->getMemberState().secondary());
 }
 
+TEST_F(StepDownTest, StepDownFailureRestoresDrainState) {
+    const auto repl = getReplCoord();
+
+    OpTimeWithTermOne opTime1(100, 1);
+    OpTimeWithTermOne opTime2(200, 1);
+
+    repl->setMyLastAppliedOpTime(opTime2);
+    repl->setMyLastDurableOpTime(opTime2);
+
+    // Secondaries not caught up yet.
+    ASSERT_OK(repl->setLastAppliedOptime_forTest(1, 1, opTime1));
+    ASSERT_OK(repl->setLastAppliedOptime_forTest(1, 2, opTime1));
+
+    auto electionTimeoutWhen = getReplCoord()->getElectionTimeout_forTest();
+    simulateSuccessfulV1ElectionWithoutExitingDrainMode(electionTimeoutWhen);
+    ASSERT_TRUE(repl->getMemberState().primary());
+    ASSERT(repl->getApplierState() == ReplicationCoordinator::ApplierState::Draining);
+
+    {
+        // We can't take writes yet since we're still in drain mode.
+        const auto opCtx = makeOperationContext();
+        Lock::GlobalLock lock(opCtx.get(), MODE_IX);
+        ASSERT_FALSE(getReplCoord()->canAcceptWritesForDatabase(opCtx.get(), "admin"));
+    }
+
+    // Step down where the secondary actually has to catch up before the stepDown can succeed.
+    auto result = stepDown_nonBlocking(false, Seconds(10), Seconds(60));
+
+    // Interrupt the ongoing stepdown command so that the stepdown attempt will fail.
+    {
+        stdx::lock_guard<Client> lk(*result.first.client.get());
+        result.first.opCtx->markKilled(ErrorCodes::Interrupted);
+    }
+
+    // Ensure that the stepdown command failed.
+    auto stepDownStatus = *result.second.get();
+    ASSERT_NOT_OK(stepDownStatus);
+    // Which code is returned is racy.
+    ASSERT(stepDownStatus == ErrorCodes::PrimarySteppedDown ||
+           stepDownStatus == ErrorCodes::Interrupted);
+    ASSERT_TRUE(getReplCoord()->getMemberState().primary());
+    ASSERT(repl->getApplierState() == ReplicationCoordinator::ApplierState::Draining);
+
+    // Ensure that the failed stepdown attempt didn't make us able to take writes since we're still
+    // in drain mode.
+    {
+        const auto opCtx = makeOperationContext();
+        Lock::GlobalLock lock(opCtx.get(), MODE_IX);
+        ASSERT_FALSE(getReplCoord()->canAcceptWritesForDatabase(opCtx.get(), "admin"));
+    }
+
+    // Now complete drain mode and ensure that we become capable of taking writes.
+    auto opCtx = makeOperationContext();
+    signalDrainComplete(opCtx.get());
+    ASSERT(repl->getApplierState() == ReplicationCoordinator::ApplierState::Stopped);
+
+    ASSERT_TRUE(getReplCoord()->getMemberState().primary());
+    Lock::GlobalLock lock(opCtx.get(), MODE_IX);
+    ASSERT_TRUE(getReplCoord()->canAcceptWritesForDatabase(opCtx.get(), "admin"));
+}
+
 class StepDownTestWithUnelectableNode : public StepDownTest {
 private:
     void setUp() override {