1 files changed, 25 insertions, 27 deletions

diff --git a/src/mongo/rpc/metadata/client_metadata.cpp b/src/mongo/rpc/metadata/client_metadata.cpp
index 8ac4f4a9d97..86d7230120e 100644
--- a/src/mongo/rpc/metadata/client_metadata.cpp
+++ b/src/mongo/rpc/metadata/client_metadata.cpp
@@ -43,8 +43,6 @@
 #include "mongo/db/operation_context.h"
 #include "mongo/logv2/log.h"
 #include "mongo/s/is_mongos.h"
-#include "mongo/transport/message_compressor_base.h"
-#include "mongo/transport/message_compressor_manager.h"
 #include "mongo/util/debug_util.h"
 #include "mongo/util/net/socket_utils.h"
 #include "mongo/util/processinfo.h"
@@ -158,7 +156,7 @@ ClientMetadata::ClientMetadata(BSONObj doc) {
             foundOperatingSystem);
 }
 
-StatusWith<std::string> ClientMetadata::parseApplicationDocument(const BSONObj& doc) {
+StatusWith<StringData> ClientMetadata::parseApplicationDocument(const BSONObj& doc) {
     BSONObjIterator i(doc);
 
     while (i.more()) {
@@ -175,7 +173,7 @@ StatusWith<std::string> ClientMetadata::parseApplicationDocument(const BSONObj&
                             << "' field must be a string in the client metadata document"};
             }
 
-            std::string value = str::escape(e.checkAndGetStringData().toString());
+            StringData value = e.checkAndGetStringData();
 
             if (value.size() > kMaxApplicationNameByteLength) {
                 return {ErrorCodes::ClientMetadataAppNameTooLarge,
@@ -185,11 +183,11 @@ StatusWith<std::string> ClientMetadata::parseApplicationDocument(const BSONObj&
                                       << " bytes in the client metadata document"};
             }
 
-            return std::move(value);
+            return {std::move(value)};
         }
     }
 
-    return std::string();
+    return {StringData()};
 }
 
 Status ClientMetadata::validateDriverDocument(const BSONObj& doc) {
@@ -269,7 +267,6 @@ Status ClientMetadata::validateOperatingSystemDocument(const BSONObj& doc) {
 void ClientMetadata::setMongoSMetadata(StringData hostAndPort,
                                        StringData mongosClient,
                                        StringData version) {
-    _documentWithoutMongosInfo = _document;
     BSONObjBuilder builder;
     builder.appendElements(_document);
 
@@ -280,7 +277,25 @@ void ClientMetadata::setMongoSMetadata(StringData hostAndPort,
         sub.append(kVersion, version);
     }
 
-    _document = builder.obj();
+    auto document = builder.obj();
+
+    if (!_appName.empty()) {
+        // The _appName field points into the existing _document, which we are about to replace.
+        // We must redirect _appName to point into the new doc *before* replacing the old doc. We
+        // expect the 'application' metadata of the new document to be identical to the old.
+        auto appMetaData = document[kApplication];
+        invariant(appMetaData.isABSONObj());
+
+        auto appNameEl = appMetaData[kName];
+        invariant(appNameEl.type() == BSONType::String);
+
+        auto appName = appNameEl.valueStringData();
+        invariant(appName == _appName);
+
+        _appName = appName;
+    }
+
+    _document = std::move(document);
 }
 
 void ClientMetadata::serialize(StringData driverName,
@@ -375,40 +390,23 @@ Status ClientMetadata::serializePrivate(StringData driverName,
 }
 
 StringData ClientMetadata::getApplicationName() const {
-    return StringData(_appName);
+    return _appName;
 }
 
 const BSONObj& ClientMetadata::getDocument() const {
     return _document;
 }
 
-unsigned long ClientMetadata::hashWithoutMongosInfo() const {
-    return _hashWithoutMongos.get(documentWithoutMongosInfo());
-}
-
-const BSONObj& ClientMetadata::documentWithoutMongosInfo() const {
-    return _documentWithoutMongosInfo.get(_document);
-}
-
 void ClientMetadata::logClientMetadata(Client* client) const {
     if (getDocument().isEmpty()) {
         return;
     }
 
-    auto negotiatedCompressors =
-        MessageCompressorManager::forSession(client->session()).getNegotiatedCompressors();
-    std::vector<StringData> negotiatedCompressorNames(negotiatedCompressors.size(), nullptr);
-    std::transform(
-        negotiatedCompressors.begin(),
-        negotiatedCompressors.end(),
-        negotiatedCompressorNames.begin(),
-        [](auto& messageCompressor) { return StringData(messageCompressor->getName()); });
-
     LOGV2(51800,
+          "received client metadata from {remote} {client}: {doc}",
           "client metadata",
           "remote"_attr = client->getRemote(),
           "client"_attr = client->desc(),
-          "negotiatedCompressors"_attr = negotiatedCompressorNames,
           "doc"_attr = getDocument());
 }