SERVER-30512 Omit fullDocument in change stream if it's null unless updateLookup is specified explicitly.

3 files changed, 7 insertions, 14 deletions

diff --git a/src/mongo/db/pipeline/document_source_change_stream.cpp b/src/mongo/db/pipeline/document_source_change_stream.cpp
index 973e0507f73..1eda922c388 100644
--- a/src/mongo/db/pipeline/document_source_change_stream.cpp
+++ b/src/mongo/db/pipeline/document_source_change_stream.cpp
@@ -296,7 +296,7 @@ Document DocumentSourceChangeStream::Transformation::applyTransformation(const D
     // Non-replace updates have the _id in field "o2".
     Value documentId = id.missing() ? input.getNestedField("o2._id") : id;
     StringData operationType;
-    Value fullDocument = Value(BSONNULL);
+    Value fullDocument;
     Value updateDescription;
 
     // Deal with CRUD operations and commands.
diff --git a/src/mongo/db/pipeline/document_source_change_stream_test.cpp b/src/mongo/db/pipeline/document_source_change_stream_test.cpp
index 6d558d973d5..158de011548 100644
--- a/src/mongo/db/pipeline/document_source_change_stream_test.cpp
+++ b/src/mongo/db/pipeline/document_source_change_stream_test.cpp
@@ -216,7 +216,6 @@ TEST_F(ChangeStreamStageTest, TransformUpdateFields) {
     Document expectedUpdateField{
         {DSChangeStream::kIdField, makeResumeToken(ts, nss, 1)},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kUpdateOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
         {DSChangeStream::kNamespaceField, D{{"db", nss.db()}, {"coll", nss.coll()}}},
         {DSChangeStream::kDocumentKeyField, D{{"_id", 1}}},
         {
@@ -233,7 +232,6 @@ TEST_F(ChangeStreamStageTest, TransformRemoveFields) {
     Document expectedRemoveField{
         {DSChangeStream::kIdField, makeResumeToken(ts, nss, 1)},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kUpdateOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
         {DSChangeStream::kNamespaceField, D{{"db", nss.db()}, {"coll", nss.coll()}}},
         {DSChangeStream::kDocumentKeyField, D{{"_id", 1}}},
         {
@@ -262,7 +260,6 @@ TEST_F(ChangeStreamStageTest, TransformDelete) {
     Document expectedDelete{
         {DSChangeStream::kIdField, makeResumeToken(ts, nss, 1)},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kDeleteOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
         {DSChangeStream::kNamespaceField, D{{"db", nss.db()}, {"coll", nss.coll()}}},
         {DSChangeStream::kDocumentKeyField, D{{"_id", 1}}},
     };
@@ -290,7 +287,6 @@ TEST_F(ChangeStreamStageTest, TransformInvalidate) {
     Document expectedInvalidate{
         {DSChangeStream::kIdField, makeResumeToken(ts, nss.getCommandNS())},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kInvalidateOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
     };
     for (auto& entry : {dropColl, dropDB, rename}) {
         checkTransformation(entry, expectedInvalidate);
@@ -324,7 +320,6 @@ TEST_F(ChangeStreamStageTest, TransformInvalidateRenameDropTarget) {
     Document expectedInvalidate{
         {DSChangeStream::kIdField, makeResumeToken(ts, otherColl.getCommandNS())},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kInvalidateOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
     };
     checkTransformation(rename, expectedInvalidate);
 }
@@ -401,7 +396,6 @@ TEST_F(ChangeStreamStageTest, CloseCursorOnInvalidateEntries) {
     Document expectedInvalidate{
         {DSChangeStream::kIdField, makeResumeToken(ts, nss.getCommandNS())},
         {DSChangeStream::kOperationTypeField, DSChangeStream::kInvalidateOpType},
-        {DSChangeStream::kFullDocumentField, BSONNULL},
     };
 
     auto next = closeCursor->getNext();
diff --git a/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp b/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
index 0e156287125..c1d0c6d10fa 100644
--- a/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
+++ b/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
@@ -219,12 +219,11 @@ TEST_F(DocumentSourceLookupChangePostImageTest, ShouldPropagatePauses) {
     auto mockLocalSource = DocumentSourceMock::create(
         {Document{{"documentKey", Document{{"_id", 0}}},
                   {"operationType", "insert"_sd},
-                  {"fullDocument", Document{{"_id", 0}}},
-                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}}},
+                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}},
+                  {"fullDocument", Document{{"_id", 0}}}},
          DocumentSource::GetNextResult::makePauseExecution(),
          Document{{"documentKey", Document{{"_id", 1}}},
                   {"operationType", "update"_sd},
-                  {"fullDocument", BSONNULL},
                   {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}}},
          DocumentSource::GetNextResult::makePauseExecution()});
 
@@ -242,8 +241,8 @@ TEST_F(DocumentSourceLookupChangePostImageTest, ShouldPropagatePauses) {
         next.releaseDocument(),
         (Document{{"documentKey", Document{{"_id", 0}}},
                   {"operationType", "insert"_sd},
-                  {"fullDocument", Document{{"_id", 0}}},
-                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}}}));
+                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}},
+                  {"fullDocument", Document{{"_id", 0}}}}));
 
     ASSERT_TRUE(lookupChangeStage->getNext().isPaused());
 
@@ -253,8 +252,8 @@ TEST_F(DocumentSourceLookupChangePostImageTest, ShouldPropagatePauses) {
         next.releaseDocument(),
         (Document{{"documentKey", Document{{"_id", 1}}},
                   {"operationType", "update"_sd},
-                  {"fullDocument", Document{{"_id", 1}}},
-                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}}}));
+                  {"ns", Document{{"db", expCtx->ns.db()}, {"coll", expCtx->ns.coll()}}},
+                  {"fullDocument", Document{{"_id", 1}}}}));
 
     ASSERT_TRUE(lookupChangeStage->getNext().isPaused());