SERVER-45692 add explicit RWC to inter-node commands (even if merely kImplicitDefault)

5 files changed, 75 insertions, 52 deletions

diff --git a/src/mongo/shell/encrypted_dbclient_base.cpp b/src/mongo/shell/encrypted_dbclient_base.cpp
index 883453e11db..f08af53e152 100644
--- a/src/mongo/shell/encrypted_dbclient_base.cpp
+++ b/src/mongo/shell/encrypted_dbclient_base.cpp
@@ -500,15 +500,23 @@ JS::Value EncryptedDBClientBase::getCollection() const {
 }
 
 
-std::unique_ptr<DBClientCursor> EncryptedDBClientBase::query(const NamespaceStringOrUUID& nsOrUuid,
-                                                             Query query,
-                                                             int nToReturn,
-                                                             int nToSkip,
-                                                             const BSONObj* fieldsToReturn,
-                                                             int queryOptions,
-                                                             int batchSize) {
-    return _conn->query(
-        nsOrUuid, query, nToReturn, nToSkip, fieldsToReturn, queryOptions, batchSize);
+std::unique_ptr<DBClientCursor> EncryptedDBClientBase::query(
+    const NamespaceStringOrUUID& nsOrUuid,
+    Query query,
+    int nToReturn,
+    int nToSkip,
+    const BSONObj* fieldsToReturn,
+    int queryOptions,
+    int batchSize,
+    boost::optional<BSONObj> readConcernObj) {
+    return _conn->query(nsOrUuid,
+                        query,
+                        nToReturn,
+                        nToSkip,
+                        fieldsToReturn,
+                        queryOptions,
+                        batchSize,
+                        readConcernObj);
 }
 
 bool EncryptedDBClientBase::isFailed() const {
diff --git a/src/mongo/shell/encrypted_dbclient_base.h b/src/mongo/shell/encrypted_dbclient_base.h
index 518c3631a5f..406c5884391 100644
--- a/src/mongo/shell/encrypted_dbclient_base.h
+++ b/src/mongo/shell/encrypted_dbclient_base.h
@@ -118,13 +118,15 @@ public:
     void trace(JSTracer* trc) final;
 
     using DBClientBase::query;
-    std::unique_ptr<DBClientCursor> query(const NamespaceStringOrUUID& nsOrUuid,
-                                          Query query,
-                                          int nToReturn,
-                                          int nToSkip,
-                                          const BSONObj* fieldsToReturn,
-                                          int queryOptions,
-                                          int batchSize) final;
+    std::unique_ptr<DBClientCursor> query(
+        const NamespaceStringOrUUID& nsOrUuid,
+        Query query,
+        int nToReturn,
+        int nToSkip,
+        const BSONObj* fieldsToReturn,
+        int queryOptions,
+        int batchSize,
+        boost::optional<BSONObj> readConcernObj = boost::none) final;
 
     bool isFailed() const final;
 
diff --git a/src/mongo/shell/feature_compatibility_version.js b/src/mongo/shell/feature_compatibility_version.js
index 0894a2a0fd2..599e7a4c79f 100644
--- a/src/mongo/shell/feature_compatibility_version.js
+++ b/src/mongo/shell/feature_compatibility_version.js
@@ -25,7 +25,13 @@ function checkFCV(adminDB, version, targetVersion) {
     assert.eq(res.featureCompatibilityVersion.version, version, tojson(res));
     assert.eq(res.featureCompatibilityVersion.targetVersion, targetVersion, tojson(res));
 
-    let doc = adminDB.system.version.findOne({_id: "featureCompatibilityVersion"});
+    // This query specifies an explicit readConcern because some FCV tests pass a connection that
+    // has manually run isMaster with internalClient, and mongod expects internalClients (ie. other
+    // cluster members) to include read/write concern (on commands that accept read/write concern).
+    let doc = adminDB.system.version.find({_id: "featureCompatibilityVersion"})
+                  .limit(1)
+                  .readConcern("local")
+                  .next();
     assert.eq(doc.version, version, tojson(doc));
     assert.eq(doc.targetVersion, targetVersion, tojson(doc));
 }
diff --git a/src/mongo/shell/mongo.js b/src/mongo/shell/mongo.js
index 2503a989d74..1fe4a678b20 100644
--- a/src/mongo/shell/mongo.js
+++ b/src/mongo/shell/mongo.js
@@ -484,6 +484,22 @@ Mongo.prototype.readMode = function() {
     return this._readMode;
 };
 
+/**
+ * Run a function while forcing a certain readMode, and then return the readMode to its original
+ * setting afterwards. Passes this connection to the given function, and returns the function's
+ * result.
+ */
+Mongo.prototype._runWithForcedReadMode = function(forcedReadMode, fn) {
+    let origReadMode = this.readMode();
+    this.forceReadMode(forcedReadMode);
+    try {
+        var res = fn(this);
+    } finally {
+        this.forceReadMode(origReadMode);
+    }
+    return res;
+};
+
 //
 // Write Concern can be set at the connection level, and is used for all write operations unless
 // overridden at the collection level.
diff --git a/src/mongo/shell/replsettest.js b/src/mongo/shell/replsettest.js
index 46f1e7bbab5..e20de8ff38f 100644
--- a/src/mongo/shell/replsettest.js
+++ b/src/mongo/shell/replsettest.js
@@ -1672,17 +1672,6 @@ var ReplSetTest = function(opts) {
               "established on " + id);
     };
 
-    function _runInCommandReadMode(conn, fn) {
-        let origReadMode = conn.readMode();
-        conn.forceReadMode("commands");
-        try {
-            var res = fn();
-        } finally {
-            conn.forceReadMode(origReadMode);
-        }
-        return res;
-    }
-
     // Wait until the optime of the specified type reaches the primary's last applied optime. Blocks
     // on all secondary nodes or just 'slaves', if specified. The timeout will reset if any of the
     // secondaries makes progress.
@@ -1747,13 +1736,13 @@ var ReplSetTest = function(opts) {
             var slaveName = slave.host;
 
             var slaveConfigVersion =
-                _runInCommandReadMode(slave,
-                                      () => slave.getDB("local")['system.replset']
-                                                .find()
-                                                .readConcern("local")
-                                                .limit(1)
-                                                .next()
-                                                .version);
+                slave._runWithForcedReadMode("commands",
+                                             () => slave.getDB("local")['system.replset']
+                                                       .find()
+                                                       .readConcern("local")
+                                                       .limit(1)
+                                                       .next()
+                                                       .version);
 
             if (masterConfigVersion != slaveConfigVersion) {
                 print("ReplSetTest awaitReplication: secondary #" + secondaryCount + ", " +
@@ -1763,13 +1752,13 @@ var ReplSetTest = function(opts) {
                 if (slaveConfigVersion > masterConfigVersion) {
                     master = self.getPrimary();
                     masterConfigVersion =
-                        _runInCommandReadMode(master,
-                                              () => master.getDB("local")['system.replset']
-                                                        .find()
-                                                        .readConcern("local")
-                                                        .limit(1)
-                                                        .next()
-                                                        .version);
+                        master._runWithForcedReadMode("commands",
+                                                      () => master.getDB("local")['system.replset']
+                                                                .find()
+                                                                .readConcern("local")
+                                                                .limit(1)
+                                                                .next()
+                                                                .version);
                     masterName = master.host;
 
                     print("ReplSetTest awaitReplication: optime for primary, " + masterName +
@@ -2455,7 +2444,8 @@ var ReplSetTest = function(opts) {
                 }
 
                 try {
-                    return _runInCommandReadMode(this.mongo, () => operation(this.cursor));
+                    return this.mongo._runWithForcedReadMode("commands",
+                                                             () => operation(this.cursor));
                 } catch (err) {
                     print("Error: " + name + " threw '" + err.message + "' on " + this.mongo.host);
                     // Occasionally, the capped collection will get truncated while we are iterating
@@ -2491,20 +2481,21 @@ var ReplSetTest = function(opts) {
                 // changed "cursorTimeoutMillis" to a short time period.
                 this._cursorExhausted = false;
                 // Although this line sets the read concern, it does not need to be called via
-                // _runInCommandReadMode() because it only creates the client-side cursor.  It's not
-                // until next()/hasNext() are called that the find command gets sent to the server.
+                // _runWithForcedReadMode() because it only creates the client-side cursor.  It's
+                // not until next()/hasNext() are called that the find command gets sent to the
+                // server.
                 this.cursor =
                     coll.find(query).sort({$natural: -1}).noCursorTimeout().readConcern("local");
             };
 
             this.getFirstDoc = function() {
-                return _runInCommandReadMode(this.mongo,
-                                             () => this.getOplogColl()
-                                                       .find()
-                                                       .sort({$natural: 1})
-                                                       .readConcern("local")
-                                                       .limit(-1)
-                                                       .next());
+                return this.mongo._runWithForcedReadMode("commands",
+                                                         () => this.getOplogColl()
+                                                                   .find()
+                                                                   .sort({$natural: 1})
+                                                                   .readConcern("local")
+                                                                   .limit(-1)
+                                                                   .next());
             };
 
             this.getOplogColl = function() {