SERVER-30166 Support pipelines running on mongos only

1 files changed, 5 insertions, 0 deletions

diff --git a/src/mongo/db/pipeline/document_source.h b/src/mongo/db/pipeline/document_source.h
index b0793113863..5c10259ce4a 100644
--- a/src/mongo/db/pipeline/document_source.h
+++ b/src/mongo/db/pipeline/document_source.h
@@ -156,6 +156,11 @@ public:
         // must also override getModifiedPaths() to provide information about which particular
         // $match predicates be swapped before itself.
         bool canSwapWithMatch = false;
+
+        // Extends HostTypeRequirement::kAnyShardOrMongos to indicate that a document source
+        // must run on whatever node initially received the pipeline.
+        // This can be a mongod directly, but mongos must not forward to a mongod.
+        bool allowedToForwardFromMongos = true;
     };
 
     using HostTypeRequirement = StageConstraints::HostTypeRequirement;