From 34646a414c15b016a10bbc95f4c1bd33baa88b97 Mon Sep 17 00:00:00 2001
From: Adam Parrish <aparrish@nyu.edu>
Date: Thu, 10 Nov 2011 12:03:51 -0800
Subject: [PATCH] Fixes bug using positional operator to update embedded
 documents.

append_field wasn't getting reset to True in the loop, so fields wouldn't
get appended to clean_fields after str was encountered

[#354]
---
 AUTHORS                 |  1 +
 docs/changelog.rst      |  1 +
 mongoengine/queryset.py |  2 +-
 tests/queryset.py       | 28 ++++++++++++++++++++++++++++
 4 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 9ebc0054..4f68be2f 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -73,4 +73,5 @@ that much better:
  * Julien Rebetez
  * Marc Tamlyn
  * Karim Allah
+ * Adam Parrish
 
diff --git a/docs/changelog.rst b/docs/changelog.rst
index dbb4a728..53943127 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -5,6 +5,7 @@ Changelog
 Changes in dev
 ==============
 
+- Fixed positional operator when replacing embedded documents
 - Added Non-Django Style choices back (you can have either)
 - Fixed __repr__ of a sliced queryset
 - Added recursive validation error of documents / complex fields
diff --git a/mongoengine/queryset.py b/mongoengine/queryset.py
index 8ebebe3a..6f01b765 100644
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
@@ -1276,8 +1276,8 @@ class QuerySet(object):
                 parts = []
 
                 cleaned_fields = []
-                append_field = True
                 for field in fields:
+                    append_field = True
                     if isinstance(field, str):
                         # Convert the S operator to $
                         if field == 'S':
diff --git a/tests/queryset.py b/tests/queryset.py
index 5f5e78be..60adae37 100644
--- a/tests/queryset.py
+++ b/tests/queryset.py
@@ -378,6 +378,34 @@ class QuerySetTest(unittest.TestCase):
         self.assertRaises(OperationError, update_nested)
         Simple.drop_collection()
 
+    def test_update_using_positional_operator_embedded_document(self):
+        """Ensure that the embedded documents can be updated using the positional
+        operator."""
+
+        class Vote(EmbeddedDocument):
+            score = IntField()
+
+        class Comment(EmbeddedDocument):
+            by = StringField()
+            votes = EmbeddedDocumentField(Vote)
+
+        class BlogPost(Document):
+            title = StringField()
+            comments = ListField(EmbeddedDocumentField(Comment))
+
+        BlogPost.drop_collection()
+
+        c1 = Comment(by="joe", votes=Vote(score=3))
+        c2 = Comment(by="jane", votes=Vote(score=7))
+
+        BlogPost(title="ABC", comments=[c1, c2]).save()
+
+        BlogPost.objects(comments__by="joe").update(set__comments__S__votes=Vote(score=4))
+
+        post = BlogPost.objects.first()
+        self.assertEquals(post.comments[0].by, 'joe')
+        self.assertEquals(post.comments[0].votes.score, 4)
+
     def test_mapfield_update(self):
         """Ensure that the MapField can be updated."""
         class Member(EmbeddedDocument):