SERVER-12931 add failure status to working set if child stage fails without providing reason

1 files changed, 11 insertions, 0 deletions

diff --git a/src/mongo/db/exec/or.cpp b/src/mongo/db/exec/or.cpp
index 8387369c900..83a441d3896 100644
--- a/src/mongo/db/exec/or.cpp
+++ b/src/mongo/db/exec/or.cpp
@@ -28,6 +28,8 @@
 
 #include "mongo/db/exec/or.h"
 #include "mongo/db/exec/filter.h"
+#include "mongo/db/exec/working_set_common.h"
+#include "mongo/util/mongoutils/str.h"
 
 namespace mongo {
 
@@ -108,6 +110,15 @@ namespace mongo {
         }
         else if (PlanStage::FAILURE == childStatus) {
             *out = id;
+            // If a stage fails, it may create a status WSM to indicate why it
+            // failed, in which case 'id' is valid.  If ID is invalid, we
+            // create our own error message.
+            if (WorkingSet::INVALID_ID == id) {
+                mongoutils::str::stream ss;
+                ss << "OR stage failed to read in results from child " << _currentChild;
+                Status status(ErrorCodes::InternalError, ss);
+                *out = WorkingSetCommon::allocateStatusMember( _ws, status);
+            }
             return childStatus;
         }
         else {