SERVER-55596 Remove isMaster from API Version 1

3 files changed, 5 insertions, 4 deletions

diff --git a/src/mongo/client/dbclient_base.cpp b/src/mongo/client/dbclient_base.cpp
index b6944cc64c4..8af0924768d 100644
--- a/src/mongo/client/dbclient_base.cpp
+++ b/src/mongo/client/dbclient_base.cpp
@@ -580,7 +580,7 @@ void DBClientBase::logout(const string& dbname, BSONObj& info) {
 
 bool DBClientBase::isPrimary(bool& isPrimary, BSONObj* info) {
     BSONObjBuilder bob;
-    bob.append("ismaster", 1);
+    bob.append(_apiParameters.getVersion() ? "hello" : "ismaster", 1);
     if (auto wireSpec = WireSpec::instance().get(); wireSpec->isInternalClient) {
         WireSpec::appendInternalClientWireVersion(wireSpec->outgoing, &bob);
     }
@@ -589,7 +589,8 @@ bool DBClientBase::isPrimary(bool& isPrimary, BSONObj* info) {
     if (info == nullptr)
         info = &o;
     bool ok = runCommand("admin", bob.obj(), *info);
-    isPrimary = info->getField("ismaster").trueValue();
+    isPrimary =
+        info->getField(_apiParameters.getVersion() ? "isWritablePrimary" : "ismaster").trueValue();
     return ok;
 }
 
diff --git a/src/mongo/client/dbclient_connection.cpp b/src/mongo/client/dbclient_connection.cpp
index a42865be5be..f40b32e76a6 100644
--- a/src/mongo/client/dbclient_connection.cpp
+++ b/src/mongo/client/dbclient_connection.cpp
@@ -186,7 +186,7 @@ executor::RemoteCommandResponse initWireVersion(
     ScopedForceOpQuery forceOpQuery{conn};
 
     BSONObjBuilder bob;
-    bob.append("isMaster", 1);
+    bob.append(conn->getApiParameters().getVersion() ? "hello" : "isMaster", 1);
 
     if (uri.isHelloOk()) {
         // Attach "helloOk: true" to the initial handshake to indicate that the client supports the
diff --git a/src/mongo/client/scanning_replica_set_monitor.cpp b/src/mongo/client/scanning_replica_set_monitor.cpp
index daef814d55c..afe643a8d14 100644
--- a/src/mongo/client/scanning_replica_set_monitor.cpp
+++ b/src/mongo/client/scanning_replica_set_monitor.cpp
@@ -988,7 +988,7 @@ void IsMasterReply::parse(const BSONObj& obj) {
         maxWireVersion = raw["maxWireVersion"].numberInt();
 
         // hidden nodes can't be master, even if they claim to be.
-        isMaster = !hidden && raw["ismaster"].trueValue();
+        isMaster = !hidden && (raw["isWritablePrimary"].trueValue() || raw["ismaster"].trueValue());
 
         if (isMaster && raw.hasField("electionId")) {
             electionId = raw["electionId"].OID();