SERVER-6993 - fix findAndModify positional operator regression with undotted query fields

2 files changed, 34 insertions, 1 deletions

diff --git a/jstests/find_and_modify_server6993.js b/jstests/find_and_modify_server6993.js
new file mode 100644
index 00000000000..b8a31915372
--- /dev/null
+++ b/jstests/find_and_modify_server6993.js
@@ -0,0 +1,9 @@
+
+c = db.find_and_modify_server6993;
+c.drop();
+ 
+c.insert( { a:[ 1, 2 ] } );
+ 
+c.findAndModify( { query:{ a:1 }, update:{ $set:{ 'a.$':5 } } } );
+ 
+assert.eq( 5, c.findOne().a[ 0 ] );
diff --git a/src/mongo/db/commands/find_and_modify.cpp b/src/mongo/db/commands/find_and_modify.cpp
index 900090a159c..0ad78239de2 100644
--- a/src/mongo/db/commands/find_and_modify.cpp
+++ b/src/mongo/db/commands/find_and_modify.cpp
@@ -123,6 +123,30 @@ namespace mongo {
                 // we're going to re-write the query to be more efficient
                 // we have to be a little careful because of positional operators
                 // maybe we can pass this all through eventually, but right now isn't an easy way
+                
+                bool hasPositionalUpdate = false;
+                {
+                    // if the update has a positional piece ($)
+                    // then we need to pull all query parts in
+                    // so here we check for $
+                    // a little hacky
+                    BSONObjIterator i( update );
+                    while ( i.more() ) {
+                        const BSONElement& elem = i.next();
+                        
+                        if ( elem.fieldName()[0] != '$' || elem.type() != Object )
+                            continue;
+
+                        BSONObjIterator j( elem.Obj() );
+                        while ( j.more() ) {
+                            if ( str::contains( j.next().fieldName(), ".$" ) ) {
+                                hasPositionalUpdate = true;
+                                break;
+                            }
+                        }
+                    }
+                }
+
                 BSONObjBuilder b( queryOriginal.objsize() + 10 );
                 b.append( doc["_id"] );
                 
@@ -137,7 +161,7 @@ namespace mongo {
                         continue;
                     }
                     
-                    if ( ! str::contains( elem.fieldName() , '.' ) ) {
+                    if ( ! hasPositionalUpdate ) {
                         // if there is a dotted field, accept we may need more query parts
                         continue;
                     }