SERVER-12596 writeConcern {} and writeConcern {wtimeout: 1000} treated like {w: 0}

2 files changed, 12 insertions, 2 deletions

diff --git a/src/mongo/db/commands/write_commands/batch_executor.cpp b/src/mongo/db/commands/write_commands/batch_executor.cpp
index f80b313fdb7..5d6ac60f105 100644
--- a/src/mongo/db/commands/write_commands/batch_executor.cpp
+++ b/src/mongo/db/commands/write_commands/batch_executor.cpp
@@ -109,12 +109,18 @@ namespace mongo {
         // TODO: Lift write concern parsing out of this entirely.
         WriteConcernOptions writeConcern;
         Status status = Status::OK();
+
+        BSONObj wcDoc;
         if ( request.isWriteConcernSet() ) {
-            status = writeConcern.parse( request.getWriteConcern() );
+            wcDoc = request.getWriteConcern();
         }
-        else {
+
+        if ( wcDoc.isEmpty() ) {
             status = writeConcern.parse( _defaultWriteConcern );
         }
+        else {
+            status = writeConcern.parse( wcDoc );
+        }
 
         if ( status.isOK() ) {
             status = validateWriteConcern( writeConcern );
diff --git a/src/mongo/db/write_concern_options.cpp b/src/mongo/db/write_concern_options.cpp
index 2658797e5e3..db18073a3ac 100644
--- a/src/mongo/db/write_concern_options.cpp
+++ b/src/mongo/db/write_concern_options.cpp
@@ -37,6 +37,9 @@ namespace mongo {
     const BSONObj WriteConcernOptions::Unacknowledged(BSON("w" << W_NONE));
 
     Status WriteConcernOptions::parse( const BSONObj& obj ) {
+        if ( obj.isEmpty() ) {
+            return Status( ErrorCodes::BadValue, "write concern object cannot be empty" );
+        }
 
         bool j = obj["j"].trueValue();
         bool fsync = obj["fsync"].trueValue();
@@ -61,6 +64,7 @@ namespace mongo {
         else if ( e.eoo() ||
                   e.type() == jstNULL ||
                   e.type() == Undefined ) {
+            wNumNodes = 1;
         }
         else {
             return Status( ErrorCodes::BadValue, "w has to be a number or a string" );