1 files changed, 15 insertions, 3 deletions
diff --git a/src/mongo/db/query/index_bounds_builder.cpp b/src/mongo/db/query/index_bounds_builder.cpp
index aa05e986aed..4176823172e 100644
--- a/src/mongo/db/query/index_bounds_builder.cpp
+++ b/src/mongo/db/query/index_bounds_builder.cpp
@@ -129,11 +129,10 @@ const Interval kHashedNullInterval =
     IndexBoundsBuilder::makePointInterval(ExpressionMapping::hash(kNullElementObj.firstElement()));
 
 Interval makeUndefinedPointInterval(bool isHashed) {
-    return isHashed ? kHashedUndefinedInterval
-                    : IndexBoundsBuilder::makePointInterval(kUndefinedElementObj);
+    return isHashed ? kHashedUndefinedInterval : IndexBoundsBuilder::kUndefinedPointInterval;
 }
 Interval makeNullPointInterval(bool isHashed) {
-    return isHashed ? kHashedNullInterval : IndexBoundsBuilder::makePointInterval(kNullElementObj);
+    return isHashed ? kHashedNullInterval : IndexBoundsBuilder::kNullPointInterval;
 }
 
 void makeNullEqualityBounds(const IndexEntry& index,
@@ -501,6 +500,11 @@ void buildBoundsForQueryElementForGT(BSONElement dataElt,
 
 }  // namespace
 
+const Interval IndexBoundsBuilder::kUndefinedPointInterval =
+    IndexBoundsBuilder::makePointInterval(kUndefinedElementObj);
+const Interval IndexBoundsBuilder::kNullPointInterval =
+    IndexBoundsBuilder::makePointInterval(kNullElementObj);
+
 void IndexBoundsBuilder::_translatePredicate(const MatchExpression* expr,
                                              const BSONElement& elt,
                                              const IndexEntry& index,
@@ -1455,4 +1459,12 @@ bool IndexBoundsBuilder::isSingleInterval(const IndexBounds& bounds,
     }
 }
 
+// static
+bool IndexBoundsBuilder::isNullInterval(const OrderedIntervalList& oil) {
+    // Checks if the the intervals are [undefined, undefined] and [null, null].
+    // Note: the order is always the same (see makeNullEqualityBounds()).
+    return 2 == oil.intervals.size() && oil.intervals[0].equals(kUndefinedPointInterval) &&
+        oil.intervals[1].equals(kNullPointInterval);
+}
+
 }  // namespace mongo