Fix MapField in order to handle unicode keys.

mongoengine/dereference.py

@@ -1,5 +1,7 @@
 from bson import DBRef, SON
 
+from mongoengine.python_support import txt_type
+
 from base import (
     BaseDict, BaseList, EmbeddedDocumentList,
     TopLevelDocumentMetaclass, get_document
@@ -226,7 +228,7 @@ class DeReference(object):
                         data[k]._data[field_name] = self.object_map.get(
                             (v['_ref'].collection, v['_ref'].id), v)
                     elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                        item_name = "{0}.{1}.{2}".format(name, k, field_name)
+                        item_name = txt_type("{0}.{1}.{2}").format(name, k, field_name)
                         data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=item_name)
             elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
                 item_name = '%s.%s' % (name, k) if name else name

tests/fields/fields.py

@@ -1515,6 +1515,29 @@ class FieldTest(unittest.TestCase):
             actions__friends__operation='drink',
             actions__friends__object='beer').count())
 
+    def test_map_field_unicode(self):
+
+        class Info(EmbeddedDocument):
+            description = StringField()
+            value_list = ListField(field=StringField())
+
+        class BlogPost(Document):
+            info_dict = MapField(field=EmbeddedDocumentField(Info))
+
+        BlogPost.drop_collection()
+
+        tree = BlogPost(info_dict={
+            u"éééé": {
+                'description': u"VALUE: éééé"
+            }
+        })
+
+        tree.save()
+
+        self.assertEqual(BlogPost.objects.get(id=tree.id).info_dict[u"éééé"].description, u"VALUE: éééé")
+
+        BlogPost.drop_collection()
+
     def test_embedded_db_field(self):
 
         class Embedded(EmbeddedDocument):