1 files changed, 6 insertions, 1 deletions
diff --git a/src/mongo/db/pipeline/stage_constraints.h b/src/mongo/db/pipeline/stage_constraints.h
index e955039feb2..17537069d51 100644
--- a/src/mongo/db/pipeline/stage_constraints.h
+++ b/src/mongo/db/pipeline/stage_constraints.h
@@ -343,6 +343,10 @@ struct StageConstraints {
     // Indicates that a stage is allowed within a pipeline-stlye update.
     bool isAllowedWithinUpdatePipeline = false;
 
+    // Indicates that a stage does not modify anything to do with a sort and can be done before a
+    // following merge sort.
+    bool preservesOrderAndMetadata = false;
+
     bool operator==(const StageConstraints& other) const {
         return requiredPosition == other.requiredPosition &&
             hostRequirement == other.hostRequirement && diskRequirement == other.diskRequirement &&
@@ -355,7 +359,8 @@ struct StageConstraints {
             canSwapWithMatch == other.canSwapWithMatch &&
             canSwapWithSkippingOrLimitingStage == other.canSwapWithSkippingOrLimitingStage &&
             isAllowedWithinUpdatePipeline == other.isAllowedWithinUpdatePipeline &&
-            unionRequirement == other.unionRequirement;
+            unionRequirement == other.unionRequirement &&
+            preservesOrderAndMetadata == other.preservesOrderAndMetadata;
     }
 };
 }  // namespace mongo