Revert "SERVER-23833 DocumentSourceLookup::getOutputSorts correctly truncates input sort set."

This reverts commit 44abb8db32a6fad705854793e397961dfc72d09e.

Unit tests QueuedDataStageTest and SortStageTest are failing.

3 files changed, 31 insertions, 32 deletions

diff --git a/src/mongo/db/pipeline/document_source.h b/src/mongo/db/pipeline/document_source.h
index a2a534e7aca..99197592d23 100644
--- a/src/mongo/db/pipeline/document_source.h
+++ b/src/mongo/db/pipeline/document_source.h
@@ -1485,10 +1485,7 @@ public:
                                                    Pipeline::SourceContainer* container) final;
     GetDepsReturn getDependencies(DepsTracker* deps) const final;
     void dispose() final;
-
-    BSONObjSet getOutputSorts() final {
-        return DocumentSource::truncateSortSet(pSource->getOutputSorts(), {_as.getPath(false)});
-    }
+    BSONObjSet getOutputSorts() final;
 
     bool needsPrimaryShard() const final {
         return true;
diff --git a/src/mongo/db/pipeline/document_source_lookup.cpp b/src/mongo/db/pipeline/document_source_lookup.cpp
index c4e6b72947a..a3e7f29ec77 100644
--- a/src/mongo/db/pipeline/document_source_lookup.cpp
+++ b/src/mongo/db/pipeline/document_source_lookup.cpp
@@ -326,6 +326,32 @@ BSONObj DocumentSourceLookUp::queryForInput(const Document& input,
     return query.obj();
 }
 
+BSONObjSet DocumentSourceLookUp::getOutputSorts() {
+    BSONObjSet out;
+
+    BSONObjSet inputSort = pSource->getOutputSorts();
+    std::string asPath = _as.getPath(false);
+
+    for (auto&& sortObj : inputSort) {
+        // Truncate each sortObj at the '_as' path.
+        BSONObjBuilder outputSort;
+
+        for (BSONElement fieldSort : sortObj) {
+            if (fieldSort.fieldNameStringData() == asPath) {
+                break;
+            }
+            outputSort.append(fieldSort);
+        }
+
+        BSONObj outSortObj = outputSort.obj();
+        if (!outSortObj.isEmpty()) {
+            out.insert(outSortObj);
+        }
+    }
+
+    return out;
+}
+
 boost::optional<Document> DocumentSourceLookUp::unwindResult() {
     const boost::optional<FieldPath> indexPath(_unwindSrc->indexPath());
 
diff --git a/src/mongo/db/pipeline/document_source_test.cpp b/src/mongo/db/pipeline/document_source_test.cpp
index b8f96fd1f60..c7fcdab4675 100644
--- a/src/mongo/db/pipeline/document_source_test.cpp
+++ b/src/mongo/db/pipeline/document_source_test.cpp
@@ -3352,11 +3352,11 @@ TEST(ObjectForMatch, ShouldExtractEntireArrayFromPrefixOfDottedField) {
 namespace DocumentSourceLookUp {
 using mongo::DocumentSourceLookUp;
 
-class OutputSortTruncatesOnEquality : public Mock::Base {
+class OutputSort : public Mock::Base {
 public:
     void run() {
         intrusive_ptr<DocumentSourceMock> source = DocumentSourceMock::create();
-        source->sorts = {BSON("a" << 1 << "d.e" << 1 << "c" << 1)};
+        source->sorts = {BSON("a" << 1 << "d.e" << 1)};
         intrusive_ptr<DocumentSource> lookup =
             DocumentSourceLookUp::createFromBson(BSON("$lookup" << BSON("from"
                                                                         << "a"
@@ -3372,30 +3372,7 @@ public:
         BSONObjSet outputSort = lookup->getOutputSorts();
 
         ASSERT_EQUALS(outputSort.count(BSON("a" << 1)), 1U);
-        ASSERT_EQUALS(outputSort.size(), 1U);
-    }
-};
-
-class OutputSortTruncatesOnPrefix : public Mock::Base {
-public:
-    void run() {
-        intrusive_ptr<DocumentSourceMock> source = DocumentSourceMock::create();
-        source->sorts = {BSON("a" << 1 << "d.e" << 1 << "c" << 1)};
-        intrusive_ptr<DocumentSource> lookup =
-            DocumentSourceLookUp::createFromBson(BSON("$lookup" << BSON("from"
-                                                                        << "a"
-                                                                        << "localField"
-                                                                        << "b"
-                                                                        << "foreignField"
-                                                                        << "c"
-                                                                        << "as"
-                                                                        << "d")).firstElement(),
-                                                 ctx());
-        lookup->setSource(source.get());
-
-        BSONObjSet outputSort = lookup->getOutputSorts();
-
-        ASSERT_EQUALS(outputSort.count(BSON("a" << 1)), 1U);
+        ASSERT_EQUALS(outputSort.count(BSON("d.e" << 1)), 0U);
         ASSERT_EQUALS(outputSort.size(), 1U);
     }
 };
@@ -3519,8 +3496,7 @@ public:
         add<DocumentSourceGeoNear::LimitCoalesce>();
         add<DocumentSourceGeoNear::OutputSort>();
 
-        add<DocumentSourceLookUp::OutputSortTruncatesOnEquality>();
-        add<DocumentSourceLookUp::OutputSortTruncatesOnPrefix>();
+        add<DocumentSourceLookUp::OutputSort>();
 
         add<DocumentSourceMatch::RedactSafePortion>();
         add<DocumentSourceMatch::Coalesce>();