SERVER-6659 - fix find_and_modify when upserting a new doc and original query won't work anymore

Author: erh

jstests/find_and_modify_server6659.js

@@ -0,0 +1,7 @@
+
+t = db.find_and_modify_server6659;
+t.drop();
+
+x = t.findAndModify({query:{f:1}, update:{$set:{f:2}}, upsert:true, new:true})
+assert.eq( 2, x.f );
+assert.eq( 2, t.findOne().f );

src/mongo/db/commands/find_and_modify.cpp

@@ -171,9 +171,13 @@ namespace mongo {
                         _appendHelper( result , doc , found , fields );
                     }
 
-                    updateObjects( ns.c_str() , update , queryModified , upsert , false , true , cc().curop()->debug() );
+                    UpdateResult res = updateObjects( ns.c_str() , update , queryModified , upsert , false , true , cc().curop()->debug() );
 
                     if ( returnNew ) {
+                        if ( ! res.existing && res.upserted.isSet() ) {
+                            queryModified = BSON( "_id" << res.upserted );
+                        }
+                        log() << "queryModified: " << queryModified << endl;
                         verify( Helpers::findOne( ns.c_str() , queryModified , doc ) );
                         _appendHelper( result , doc , true , fields );
                     }