SERVER-45396 Fix the 'me' field in isMaster responses when using splithorizon

(cherry picked from commit a1a1e4f0c14ab71a5fc8bc7913af25571089b65f)

2 files changed, 23 insertions, 3 deletions

diff --git a/jstests/ssl/repl_ssl_split_horizon.js b/jstests/ssl/repl_ssl_split_horizon.js
index ecd90383685..11bbf64f8dd 100644
--- a/jstests/ssl/repl_ssl_split_horizon.js
+++ b/jstests/ssl/repl_ssl_split_horizon.js
@@ -107,6 +107,11 @@
 
     var checkExpectedHorizon = function(url, memberIndex, expectedHostname) {
         // Run isMaster in the shell and check that we get the expected hostname back
+        const assertion = (memberIndex === "me")
+            ? ("assert(db.runCommand({isMaster: 1})['me'] == '" + expectedHostname + "')")
+            : ("assert(db.runCommand({isMaster: 1})['hosts'][" + memberIndex + "] == '" +
+               expectedHostname + "')");
+
         var argv = [
             'env',
             "HOSTALIASES=" + hostsFile,
@@ -114,8 +119,7 @@
             './mongo',
             url,
             '--eval',
-            ("assert(db.runCommand({isMaster: 1})['hosts'][" + memberIndex + "] == '" +
-             expectedHostname + "')")
+            assertion
         ];
         return runMongoProgram(...argv);
     };
@@ -126,6 +130,9 @@
     assert.eq(checkExpectedHorizon(defaultURL, 0, node0localHostname),
               0,
               "localhost does not return horizon");
+    assert.eq(checkExpectedHorizon(defaultURL, "me", node0localHostname),
+              0,
+              "localhost does not return horizon");
     assert.eq(checkExpectedHorizon(defaultURL, 1, node1localHostname),
               0,
               "localhost does not return horizon");
@@ -136,6 +143,9 @@
     assert.eq(checkExpectedHorizon(horizonURL, 0, node0horizonHostname),
               0,
               "does not return horizon as expected");
+    assert.eq(checkExpectedHorizon(horizonURL, "me", node0horizonHostname),
+              0,
+              "does not return horizon as expected");
     assert.eq(checkExpectedHorizon(horizonURL, 1, node1horizonHostname),
               0,
               "does not return horizon as expected");
@@ -147,6 +157,9 @@
     assert.eq(checkExpectedHorizon(horizonMissingURL, 0, node0localHostname),
               0,
               "does not return localhost as expected");
+    assert.eq(checkExpectedHorizon(horizonMissingURL, "me", node0localHostname),
+              0,
+              "does not return localhost as expected");
     assert.eq(checkExpectedHorizon(horizonMissingURL, 1, node1localHostname),
               0,
               "does not return localhost as expected");
@@ -165,6 +178,9 @@
     assert.eq(checkExpectedHorizon(horizonMissingURL, 0, node0horizonMissingHostname),
               0,
               "does not return horizon as expected");
+    assert.eq(checkExpectedHorizon(horizonMissingURL, "me", node0horizonMissingHostname),
+              0,
+              "does not return horizon as expected");
     assert.eq(checkExpectedHorizon(horizonMissingURL, 1, node1horizonMissingHostname),
               0,
               "does not return horizon as expected");
@@ -186,6 +202,10 @@
     assert.eq(checkExpectedHorizon(horizonDifferentPortURL, 0, node0horizonHostnameDifferentPort),
               0,
               "does not return horizon as expected");
+    assert.eq(
+        checkExpectedHorizon(horizonDifferentPortURL, "me", node0horizonHostnameDifferentPort),
+        0,
+        "does not return horizon as expected");
     assert.eq(checkExpectedHorizon(horizonDifferentPortURL, 1, node1horizonHostnameDifferentPort),
               0,
               "does not return horizon as expected");
diff --git a/src/mongo/db/repl/topology_coordinator.cpp b/src/mongo/db/repl/topology_coordinator.cpp
index 1247710891e..0cd9ff8fa7a 100644
--- a/src/mongo/db/repl/topology_coordinator.cpp
+++ b/src/mongo/db/repl/topology_coordinator.cpp
@@ -2272,7 +2272,7 @@ void TopologyCoordinator::fillIsMasterForReplSet(IsMasterResponse* const respons
             response->addTag(tagKey, tagConfig.getTagValue(*tag));
         }
     }
-    response->setMe(selfConfig.getHostAndPort());
+    response->setMe(selfConfig.getHostAndPort(horizon));
     if (_iAmPrimary()) {
         response->setElectionId(_electionId);
     }