SERVER-33135 Remove metadata accessors from command reply APIs

Now that OP_COMMAND is dead, all remaining implementations return the same
BSONObj for data and metadata.

8 files changed, 17 insertions, 58 deletions

diff --git a/src/mongo/rpc/legacy_reply.cpp b/src/mongo/rpc/legacy_reply.cpp
index d21b880e60c..c6ba4bfbb02 100644
--- a/src/mongo/rpc/legacy_reply.cpp
+++ b/src/mongo/rpc/legacy_reply.cpp
@@ -102,10 +102,6 @@ LegacyReply::LegacyReply(const Message* message) {
     return;
 }
 
-const BSONObj& LegacyReply::getMetadata() const {
-    return _commandReply;
-}
-
 const BSONObj& LegacyReply::getCommandReply() const {
     return _commandReply;
 }
diff --git a/src/mongo/rpc/legacy_reply.h b/src/mongo/rpc/legacy_reply.h
index f283bb954ec..b428319d5a7 100644
--- a/src/mongo/rpc/legacy_reply.h
+++ b/src/mongo/rpc/legacy_reply.h
@@ -41,7 +41,7 @@ namespace rpc {
 /**
  * Immutable view of an OP_REPLY legacy-style command reply.
  */
-class LegacyReply : public ReplyInterface {
+class LegacyReply final : public ReplyInterface {
 public:
     /**
      * Construct a Reply from a Message.
@@ -50,12 +50,6 @@ public:
     explicit LegacyReply(const Message* message);
 
     /**
-     * Accessor for the metadata object. Metadata is generally used for information
-     * that is independent of any specific command, e.g. auditing information.
-     */
-    const BSONObj& getMetadata() const final;
-
-    /**
      * The result of executing the command.
      */
     const BSONObj& getCommandReply() const final;
diff --git a/src/mongo/rpc/legacy_reply_builder.cpp b/src/mongo/rpc/legacy_reply_builder.cpp
index 78663e9f75f..1d88eb96aa5 100644
--- a/src/mongo/rpc/legacy_reply_builder.cpp
+++ b/src/mongo/rpc/legacy_reply_builder.cpp
@@ -54,7 +54,7 @@ LegacyReplyBuilder::~LegacyReplyBuilder() {}
 
 LegacyReplyBuilder& LegacyReplyBuilder::setCommandReply(Status nonOKStatus,
                                                         BSONObj extraErrorInfo) {
-    invariant(_state == State::kCommandReply);
+    invariant(!_haveCommandReply);
     if (nonOKStatus == ErrorCodes::StaleConfig) {
         _staleConfigError = true;
 
@@ -77,32 +77,25 @@ LegacyReplyBuilder& LegacyReplyBuilder::setCommandReply(Status nonOKStatus,
 }
 
 LegacyReplyBuilder& LegacyReplyBuilder::setRawCommandReply(const BSONObj& commandReply) {
-    invariant(_state == State::kCommandReply);
+    invariant(!_haveCommandReply);
+    _bodyOffset = _builder.len();
     commandReply.appendSelfToBufBuilder(_builder);
-    _state = State::kMetadata;
+    _haveCommandReply = true;
     return *this;
 }
 
 BSONObjBuilder LegacyReplyBuilder::getBodyBuilder() {
-    if (_state == State::kCommandReply) {
+    if (!_haveCommandReply) {
         auto bob = BSONObjBuilder(_builder);
         _bodyOffset = bob.offset();
-        _state = State::kMetadata;
+        _haveCommandReply = true;
         return bob;
     }
 
-    invariant(_state == State::kMetadata);
     invariant(_bodyOffset);
     return BSONObjBuilder(BSONObjBuilder::ResumeBuildingTag{}, _builder, _bodyOffset);
 }
 
-LegacyReplyBuilder& LegacyReplyBuilder::setMetadata(const BSONObj& metadata) {
-    invariant(_state == State::kMetadata);
-    BSONObjBuilder(BSONObjBuilder::ResumeBuildingTag(), _builder, sizeof(QueryResult::Value))
-        .appendElements(metadata);
-    _state = State::kOutputDocs;
-    return *this;
-}
 
 Protocol LegacyReplyBuilder::getProtocol() const {
     return rpc::Protocol::kOpQuery;
@@ -116,20 +109,20 @@ void LegacyReplyBuilder::reserveBytes(const std::size_t bytes) {
 void LegacyReplyBuilder::reset() {
     // If we are in State::kMetadata, we are already in the 'start' state, so by
     // immediately returning, we save a heap allocation.
-    if (_state == State::kCommandReply) {
+    if (!_haveCommandReply) {
         return;
     }
     _builder.reset();
     _builder.skip(sizeof(QueryResult::Value));
     _message.reset();
-    _state = State::kCommandReply;
+    _haveCommandReply = false;
     _staleConfigError = false;
     _bodyOffset = 0;
 }
 
 
 Message LegacyReplyBuilder::done() {
-    invariant(_state == State::kOutputDocs);
+    invariant(_haveCommandReply);
 
     QueryResult::View qr = _builder.buf();
 
@@ -148,7 +141,6 @@ Message LegacyReplyBuilder::done() {
 
     _message.setData(_builder.release());
 
-    _state = State::kDone;
     return std::move(_message);
 }
 
diff --git a/src/mongo/rpc/legacy_reply_builder.h b/src/mongo/rpc/legacy_reply_builder.h
index 4f3128bb2be..3c90dc7db4f 100644
--- a/src/mongo/rpc/legacy_reply_builder.h
+++ b/src/mongo/rpc/legacy_reply_builder.h
@@ -54,8 +54,6 @@ public:
 
     BSONObjBuilder getBodyBuilder() final;
 
-    LegacyReplyBuilder& setMetadata(const BSONObj& metadata) final;
-
     void reset() final;
 
     Message done() final;
@@ -65,14 +63,12 @@ public:
     void reserveBytes(const std::size_t bytes) final;
 
 private:
-    enum class State { kMetadata, kCommandReply, kOutputDocs, kDone };
-
-    BufBuilder _builder{};
+    BufBuilder _builder;
     std::size_t _bodyOffset = 0;
     Message _message;
-    State _state{State::kCommandReply};
+    bool _haveCommandReply = false;
     // For stale config errors we need to set the correct ResultFlag.
-    bool _staleConfigError{false};
+    bool _staleConfigError = false;
 };
 
 }  // namespace rpc
diff --git a/src/mongo/rpc/op_msg_rpc_impls.h b/src/mongo/rpc/op_msg_rpc_impls.h
index b16a9a7c0cd..ab09ffc3a2d 100644
--- a/src/mongo/rpc/op_msg_rpc_impls.h
+++ b/src/mongo/rpc/op_msg_rpc_impls.h
@@ -39,9 +39,6 @@ class OpMsgReply final : public rpc::ReplyInterface {
 public:
     explicit OpMsgReply(const Message* message) : _msg(OpMsg::parseOwned(*message)) {}
     explicit OpMsgReply(OpMsg msg) : _msg(std::move(msg)) {}
-    const BSONObj& getMetadata() const override {
-        return _msg.body;
-    }
     const BSONObj& getCommandReply() const override {
         return _msg.body;
     }
@@ -68,10 +65,6 @@ public:
     OpMsgBuilder::DocSequenceBuilder getDocSequenceBuilder(StringData name) override {
         return _builder.beginDocSequence(name);
     }
-    ReplyBuilderInterface& setMetadata(const BSONObj& metadata) override {
-        _builder.resumeBody().appendElements(metadata);
-        return *this;
-    }
     rpc::Protocol getProtocol() const override {
         return rpc::Protocol::kOpMsg;
     }
diff --git a/src/mongo/rpc/reply_builder_interface.h b/src/mongo/rpc/reply_builder_interface.h
index 64a8cab8891..e8ba5383090 100644
--- a/src/mongo/rpc/reply_builder_interface.h
+++ b/src/mongo/rpc/reply_builder_interface.h
@@ -75,8 +75,6 @@ public:
         uasserted(50875, "Only OpMsg may use document sequences");
     }
 
-    virtual ReplyBuilderInterface& setMetadata(const BSONObj& metadata) = 0;
-
     /**
      * Sets the reply for this command. If an engaged StatusWith<BSONObj> is passed, the command
      * reply will be set to the contained BSONObj, augmented with the element {ok, 1.0} if it
diff --git a/src/mongo/rpc/reply_builder_test.cpp b/src/mongo/rpc/reply_builder_test.cpp
index dd0d36a5739..2a15f519bdf 100644
--- a/src/mongo/rpc/reply_builder_test.cpp
+++ b/src/mongo/rpc/reply_builder_test.cpp
@@ -125,7 +125,7 @@ TEST(LegacyReplyBuilder, CommandError) {
     const BSONObj extraObj = extra.obj();
     rpc::LegacyReplyBuilder replyBuilder;
     replyBuilder.setCommandReply(status, extraObj);
-    replyBuilder.setMetadata(metadata);
+    replyBuilder.getBodyBuilder().appendElements(metadata);
     auto msg = replyBuilder.done();
 
     rpc::LegacyReply parsed(&msg);
@@ -136,7 +136,6 @@ TEST(LegacyReplyBuilder, CommandError) {
         return unifiedBuilder.obj();
     }());
 
-    ASSERT_BSONOBJ_EQ(parsed.getMetadata(), body);
     ASSERT_BSONOBJ_EQ(parsed.getCommandReply(), body);
 }
 
@@ -149,7 +148,7 @@ TEST(OpMsgReplyBuilder, CommandError) {
     const BSONObj extraObj = extra.obj();
     rpc::OpMsgReplyBuilder replyBuilder;
     replyBuilder.setCommandReply(status, extraObj);
-    replyBuilder.setMetadata(metadata);
+    replyBuilder.getBodyBuilder().appendElements(metadata);
     auto msg = replyBuilder.done();
 
     rpc::OpMsgReply parsed(&msg);
@@ -160,7 +159,6 @@ TEST(OpMsgReplyBuilder, CommandError) {
         return unifiedBuilder.obj();
     }());
 
-    ASSERT_BSONOBJ_EQ(parsed.getMetadata(), body);
     ASSERT_BSONOBJ_EQ(parsed.getCommandReply(), body);
 }
 
@@ -170,7 +168,7 @@ void testRoundTrip(rpc::ReplyBuilderInterface& replyBuilder, bool unifiedBodyAnd
     auto commandReply = buildEmptyCommand();
 
     replyBuilder.setCommandReply(commandReply);
-    replyBuilder.setMetadata(metadata);
+    replyBuilder.getBodyBuilder().appendElements(metadata);
 
     auto msg = replyBuilder.done();
 
@@ -184,10 +182,8 @@ void testRoundTrip(rpc::ReplyBuilderInterface& replyBuilder, bool unifiedBodyAnd
         }());
 
         ASSERT_BSONOBJ_EQ(parsed.getCommandReply(), body);
-        ASSERT_BSONOBJ_EQ(parsed.getMetadata(), body);
     } else {
         ASSERT_BSONOBJ_EQ(parsed.getCommandReply(), commandReply);
-        ASSERT_BSONOBJ_EQ(parsed.getMetadata(), metadata);
     }
 }
 
@@ -198,7 +194,7 @@ void testErrors(rpc::ReplyBuilderInterface& replyBuilder) {
     const auto status = Status(ErrorExtraInfoExample(123), "Why does this keep failing!");
 
     replyBuilder.setCommandReply(status);
-    replyBuilder.setMetadata(buildMetadata());
+    replyBuilder.getBodyBuilder().appendElements(buildMetadata());
 
     const auto msg = replyBuilder.done();
 
diff --git a/src/mongo/rpc/reply_interface.h b/src/mongo/rpc/reply_interface.h
index a5e72255d6e..c51fb686459 100644
--- a/src/mongo/rpc/reply_interface.h
+++ b/src/mongo/rpc/reply_interface.h
@@ -47,12 +47,6 @@ public:
     virtual ~ReplyInterface() = default;
 
     /**
-     * Accessor for the metadata object. Metadata is generally used for information
-     * that is independent of any specific command, e.g. auditing information.
-     */
-    virtual const BSONObj& getMetadata() const = 0;
-
-    /**
      * The result of executing the command.
      */
     virtual const BSONObj& getCommandReply() const = 0;