From 495eaa80933a10cb19c79fce5435eabb4be0dd67 Mon Sep 17 00:00:00 2001
From: Aaron <aaron@10gen.com>
Date: Wed, 8 Apr 2009 14:01:48 -0400
Subject: [PATCH] empty field spec same as missing field spec for queries

---
 db/dbmessage.h         |  2 ++
 dbtests/querytests.cpp | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/db/dbmessage.h b/db/dbmessage.h
index bdf48b5c25c..3420089af38 100644
--- a/db/dbmessage.h
+++ b/db/dbmessage.h
@@ -162,6 +162,8 @@ namespace mongo {
             if ( d.moreJSObjs() ) {
                 fields = auto_ptr< set<string> >(new set<string>());
                 d.nextJsObj().getFieldNames(*fields);
+                if ( fields->size() == 0 )
+                    fields.reset();
             }
             queryOptions = d.msg().data->dataAsInt();
         }
diff --git a/dbtests/querytests.cpp b/dbtests/querytests.cpp
index 23d49a6b72a..1a2d3f75c29 100644
--- a/dbtests/querytests.cpp
+++ b/dbtests/querytests.cpp
@@ -349,6 +349,20 @@ namespace QueryTests {
             ASSERT( !error() );
         }
     };
+
+    class EmptyFieldSpec : public ClientBase {
+    public:
+        ~EmptyFieldSpec() {
+            client().dropCollection( "querytests.EmptyFieldSpec" );            
+        }
+        void run() {
+            const char *ns = "querytests.EmptyFieldSpec";
+            client().insert( ns, BSON( "a" << 1 ) );
+            ASSERT( !client().findOne( ns, "" ).isEmpty() );
+            BSONObj empty;
+            ASSERT( !client().findOne( ns, "", &empty ).isEmpty() );            
+        }        
+    };
     
     class All : public UnitTest::Suite {
     public:
@@ -368,6 +382,7 @@ namespace QueryTests {
             add< OplogReplayMode >();
             add< ArrayId >();
             add< UnderscoreNs >();
+            add< EmptyFieldSpec >();
         }
     };