SERVER-47179: Fix crash when requesting serverStatus oplog before the oplog collection is created

(cherry picked from commit d34b92cb31a147cf29fe676081978f3ff7acd79f)

2 files changed, 24 insertions, 14 deletions

diff --git a/jstests/replsets/optime.js b/jstests/replsets/optime.js
index 3fd9aff2139..6d44c198216 100644
--- a/jstests/replsets/optime.js
+++ b/jstests/replsets/optime.js
@@ -59,7 +59,11 @@ function optimesAndWallTimesAreEqual(replTest, isPersistent) {
 var replTest = new ReplSetTest(
     {name: "replStatus", nodes: 3, oplogSize: 1, waitForKeys: true, nodeOptions: {syncdelay: 1}});
 
-replTest.startSet();
+const nodes = replTest.startSet();
+
+// Tests that serverStatus oplog returns an error if the oplog collection doesn't exist.
+assert.commandFailedWithCode(nodes[0].getDB('admin').serverStatus({oplog: true}), 17347);
+
 replTest.initiate();
 var master = replTest.getPrimary();
 replTest.awaitReplication();
diff --git a/src/mongo/db/repl/replication_info.cpp b/src/mongo/db/repl/replication_info.cpp
index bf33e4334d7..eddaf899f6f 100644
--- a/src/mongo/db/repl/replication_info.cpp
+++ b/src/mongo/db/repl/replication_info.cpp
@@ -269,21 +269,27 @@ public:
         // TODO(siyuan) Output term of OpTime
         result.append("latestOptime", replCoord->getMyLastAppliedOpTime().getTimestamp());
 
-        AutoGetCollection oplog(opCtx, NamespaceString::kRsOplogNamespace, MODE_IS);
-        auto earliestOplogTimestampFetch =
-            oplog.getCollection()->getRecordStore()->getEarliestOplogTimestamp(opCtx);
-        Timestamp earliestOplogTimestamp;
-        if (earliestOplogTimestampFetch.isOK()) {
-            earliestOplogTimestamp = earliestOplogTimestampFetch.getValue();
-        } else {
+        auto earliestOplogTimestampFetch = [&] {
+            AutoGetCollection oplog(opCtx, NamespaceString::kRsOplogNamespace, MODE_IS);
+            if (!oplog.getCollection()) {
+                return StatusWith<Timestamp>(ErrorCodes::NamespaceNotFound, "oplog doesn't exist");
+            }
+            return oplog.getCollection()->getRecordStore()->getEarliestOplogTimestamp(opCtx);
+        }();
+
+        if (earliestOplogTimestampFetch.getStatus() == ErrorCodes::OplogOperationUnsupported) {
+            // Falling back to use getSingleton if the storage engine does not support
+            // getEarliestOplogTimestamp.
             BSONObj o;
-            uassert(
-                17347,
-                "Problem reading earliest entry from oplog",
-                Helpers::getSingleton(opCtx, NamespaceString::kRsOplogNamespace.ns().c_str(), o));
-            earliestOplogTimestamp = o["ts"].timestamp();
+            if (Helpers::getSingleton(opCtx, NamespaceString::kRsOplogNamespace.ns().c_str(), o)) {
+                earliestOplogTimestampFetch = o["ts"].timestamp();
+            }
         }
-        result.append("earliestOptime", earliestOplogTimestamp);
+
+        uassert(
+            17347, "Problem reading earliest entry from oplog", earliestOplogTimestampFetch.isOK());
+        result.append("earliestOptime", earliestOplogTimestampFetch.getValue());
+
         return result.obj();
     }
 } oplogInfoServerStatus;