From 0526f577ffd39ead42936f029aed225f8dc1d48e Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Wed, 22 Aug 2012 09:27:18 +0100
Subject: [PATCH] Embedded Documents still can inherit fields
 MongoEngine/mongoengine#84

---
 mongoengine/base.py    | 22 ++++++++++++++--------
 tests/test_document.py | 15 +++++++++++++++
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/mongoengine/base.py b/mongoengine/base.py
index 3c3dcdc9..3d78aaa0 100644
--- a/mongoengine/base.py
+++ b/mongoengine/base.py
@@ -514,6 +514,18 @@ class DocumentMetaclass(type):
             if hasattr(base, '_fields'):
                 doc_fields.update(base._fields)
 
+            # Standard object mixin - merge in any Fields
+            if not hasattr(base, '_meta'):
+                base_fields = {}
+                for attr_name, attr_value in base.__dict__.iteritems():
+                    if not isinstance(attr_value, BaseField):
+                        continue
+                    attr_value.name = attr_name
+                    if not attr_value.db_field:
+                        attr_value.db_field = attr_name
+                    base_fields[attr_name] = attr_value
+                doc_fields.update(base_fields)
+
         # Discover any document fields
         field_names = {}
         for attr_name, attr_value in attrs.iteritems():
@@ -537,9 +549,8 @@ class DocumentMetaclass(type):
 
         # Set _fields and db_field maps
         attrs['_fields'] = doc_fields
-        attrs['_db_field_map'] = dict(
-            ((k, v.db_field) for k, v in doc_fields.items()
-             if k != v.db_field))
+        attrs['_db_field_map'] = dict([(k, getattr(v, 'db_field', k))
+                                        for k, v in doc_fields.iteritems()])
         attrs['_reverse_db_field_map'] = dict(
                 (v, k) for k, v in attrs['_db_field_map'].iteritems())
 
@@ -757,11 +768,6 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
                 if callable(collection):
                     meta['collection'] = collection(base)
 
-            # Standard object mixin - merge in any Fields
-            if not hasattr(base, '_meta'):
-                attrs.update(dict([(k, v) for k, v in base.__dict__.items()
-                               if issubclass(v.__class__, BaseField)]))
-
         meta.merge(attrs.get('_meta', {}))  # Top level meta
 
         # Only simple classes (direct subclasses of Document)
diff --git a/tests/test_document.py b/tests/test_document.py
index fdca119f..b8e3a775 100644
--- a/tests/test_document.py
+++ b/tests/test_document.py
@@ -2585,6 +2585,21 @@ class DocumentTest(unittest.TestCase):
 
         Person.drop_collection()
 
+    def test_object_mixins(self):
+
+        class NameMixin(object):
+            name = StringField()
+
+        class Foo(EmbeddedDocument, NameMixin):
+            quantity = IntField()
+
+        self.assertEqual(['name', 'quantity'], sorted(Foo._fields.keys()))
+
+        class Bar(Document, NameMixin):
+            widgets = StringField()
+
+        self.assertEqual(['id', 'name', 'widgets'], sorted(Bar._fields.keys()))
+
     def test_mixin_inheritance(self):
         class BaseMixIn(object):
             count = IntField()