Fix filtering by embedded_doc=None

mongoengine/connection.py

@@ -25,8 +25,7 @@ _dbs = {}
 
 def register_connection(alias, name=None, host=None, port=None,
                         read_preference=READ_PREFERENCE,
-                        username=None, password=None,
-                        authentication_source=None,
+                        username=None, password=None, authentication_source=None,
                         authentication_mechanism=None,
                         **kwargs):
     """Add a connection.
@@ -71,26 +70,20 @@ def register_connection(alias, name=None, host=None, port=None,
 
     resolved_hosts = []
     for entity in conn_host:
-
-        # Handle Mongomock
+        # Handle uri style connections
         if entity.startswith('mongomock://'):
             conn_settings['is_mock'] = True
             # `mongomock://` is not a valid url prefix and must be replaced by `mongodb://`
             resolved_hosts.append(entity.replace('mongomock://', 'mongodb://', 1))
-
-        # Handle URI style connections, only updating connection params which
-        # were explicitly specified in the URI.
         elif '://' in entity:
             uri_dict = uri_parser.parse_uri(entity)
             resolved_hosts.append(entity)
-
-            if uri_dict.get('database'):
-                conn_settings['name'] = uri_dict.get('database')
-
-            for param in ('read_preference', 'username', 'password'):
-                if uri_dict.get(param):
-                    conn_settings[param] = uri_dict[param]
-
+            conn_settings.update({
+                'name': uri_dict.get('database') or name,
+                'username': uri_dict.get('username'),
+                'password': uri_dict.get('password'),
+                'read_preference': read_preference,
+            })
             uri_options = uri_dict['options']
             if 'replicaset' in uri_options:
                 conn_settings['replicaSet'] = True

mongoengine/fields.py

@@ -577,7 +577,7 @@ class EmbeddedDocumentField(BaseField):
         return self.document_type._fields.get(member_name)
 
     def prepare_query_value(self, op, value):
-        if not isinstance(value, self.document_type):
+        if value is not None and not isinstance(value, self.document_type):
             value = self.document_type._from_son(value)
         super(EmbeddedDocumentField, self).prepare_query_value(op, value)
         return self.to_mongo(value)

tests/queryset/queryset.py

@@ -1239,7 +1239,8 @@ class QuerySetTest(unittest.TestCase):
             self.assertFalse('$orderby' in q.get_ops()[0]['query'])
 
     def test_find_embedded(self):
-        """Ensure that an embedded document is properly returned from a query.
+        """Ensure that an embedded document is properly returned from
+        a query.
         """
         class User(EmbeddedDocument):
             name = StringField()
@@ -1250,16 +1251,31 @@ class QuerySetTest(unittest.TestCase):
 
         BlogPost.drop_collection()
 
-        post = BlogPost(content='Had a good coffee today...')
-        post.author = User(name='Test User')
-        post.save()
+        BlogPost.objects.create(
+            author=User(name='Test User'),
+            content='Had a good coffee today...'
+        )
 
         result = BlogPost.objects.first()
         self.assertTrue(isinstance(result.author, User))
         self.assertEqual(result.author.name, 'Test User')
 
+    def test_find_empty_embedded(self):
+        """Ensure that you can save and find an empty embedded document."""
+        class User(EmbeddedDocument):
+            name = StringField()
+
+        class BlogPost(Document):
+            content = StringField()
+            author = EmbeddedDocumentField(User)
+
         BlogPost.drop_collection()
 
+        BlogPost.objects.create(content='Anonymous post...')
+
+        result = BlogPost.objects.get(author=None)
+        self.assertEqual(result.author, None)
+
     def test_find_dict_item(self):
         """Ensure that DictField items may be found.
         """

tests/test_connection.py

@@ -174,9 +174,19 @@ class ConnectionTest(unittest.TestCase):
         c.mongoenginetest.system.users.remove({})
 
     def test_connect_uri_without_db(self):
-        """Ensure connect() method works properly if the URI doesn't
-        include a database name.
+        """Ensure connect() method works properly with uri's without database_name
         """
+        c = connect(db='mongoenginetest', alias='admin')
+        c.admin.system.users.remove({})
+        c.mongoenginetest.system.users.remove({})
+
+        c.admin.add_user("admin", "password")
+        c.admin.authenticate("admin", "password")
+        c.mongoenginetest.add_user("username", "password")
+
+        if not IS_PYMONGO_3:
+            self.assertRaises(ConnectionError, connect, "testdb_uri_bad", host='mongodb://test:password@localhost')
+
         connect("mongoenginetest", host='mongodb://localhost/')
 
         conn = get_connection()
@@ -186,31 +196,8 @@ class ConnectionTest(unittest.TestCase):
         self.assertTrue(isinstance(db, pymongo.database.Database))
         self.assertEqual(db.name, 'mongoenginetest')
 
-    def test_connect_uri_default_db(self):
-        """Ensure connect() defaults to the right database name if
-        the URI and the database_name don't explicitly specify it.
-        """
-        connect(host='mongodb://localhost/')
-
-        conn = get_connection()
-        self.assertTrue(isinstance(conn, pymongo.mongo_client.MongoClient))
-
-        db = get_db()
-        self.assertTrue(isinstance(db, pymongo.database.Database))
-        self.assertEqual(db.name, 'test')
-
-    def test_uri_without_credentials_doesnt_override_conn_settings(self):
-        """Ensure connect() uses the username & password params if the URI
-        doesn't explicitly specify them.
-        """
-        c = connect(host='mongodb://localhost/mongoenginetest',
-                    username='user',
-                    password='pass')
-
-        # OperationFailure means that mongoengine attempted authentication
-        # w/ the provided username/password and failed - that's the desired
-        # behavior. If the MongoDB URI would override the credentials
-        self.assertRaises(OperationFailure, get_db)
+        c.admin.system.users.remove({})
+        c.mongoenginetest.system.users.remove({})
 
     def test_connect_uri_with_authsource(self):
         """Ensure that the connect() method works well with