From 4972bdb3834e0b5db1c4f20cf4bf0082a813ab76 Mon Sep 17 00:00:00 2001
From: Stephan Jaekel <steph@rdev.info>
Date: Fri, 14 May 2010 14:02:39 +0200
Subject: [PATCH] ignore empty Q objects when combining Q objects.

---
 mongoengine/queryset.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mongoengine/queryset.py b/mongoengine/queryset.py
index 11b5321a..3db23baa 100644
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
@@ -59,8 +59,10 @@ class Q(object):
 
     def _combine(self, other, op):
         obj = Q()
-        obj.query = ['('] + copy.deepcopy(self.query) + [op]
-        obj.query += copy.deepcopy(other.query) + [')']
+        if self.query[0]:
+            obj.query = ['('] + copy.deepcopy(self.query) + [op] + copy.deepcopy(other.query) + [')']
+        else:
+            obj.query = copy.deepcopy(other.query)
         return obj
 
     def __or__(self, other):