From c79097879d1bf43ddc021b03563fcb25d7e73ff5 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Sun, 27 Sep 2015 20:37:47 -0700
Subject: [PATCH] Improved ObjectType instances

---
 README.md                      | 10 ++--------
 graphene/core/schema.py        |  3 ++-
 graphene/core/types.py         |  8 ++++++++
 tests/starwars_relay/schema.py |  8 ++------
 4 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/README.md b/README.md
index 0b3e0019..9e6b9e28 100644
--- a/README.md
+++ b/README.md
@@ -51,8 +51,6 @@ class Query(graphene.ObjectType):
     @resolve_only_args
     def resolve_human(self, id):
         return wrap_character(getHuman(id))
-        if human:
-            return Human(human)
 
     @resolve_only_args
     def resolve_droid(self, id):
@@ -91,9 +89,7 @@ class Ship(relay.Node):
 
     @classmethod
     def get_node(cls, id):
-        ship = getShip(id)
-        if ship:
-            return Ship(ship)
+        return Ship(getShip(id))
 
 
 class Faction(relay.Node):
@@ -107,9 +103,7 @@ class Faction(relay.Node):
 
     @classmethod
     def get_node(cls, id):
-        faction = getFaction(id)
-        if faction:
-            return Faction(faction)
+        return Faction(getFaction(id)
 
 
 class Query(graphene.ObjectType):
diff --git a/graphene/core/schema.py b/graphene/core/schema.py
index 132a4760..75f11eae 100644
--- a/graphene/core/schema.py
+++ b/graphene/core/schema.py
@@ -43,10 +43,11 @@ class Schema(object):
         return self._types[type_name]
 
     def execute(self, request='', root=None, vars=None, operation_name=None):
+        root = root or object()
         return graphql(
             self._schema,
             request=request,
-            root=root or self.query(),
+            root=self.query(root),
             vars=vars,
             operation_name=operation_name
         )
diff --git a/graphene/core/types.py b/graphene/core/types.py
index 978fd41e..6c098a57 100644
--- a/graphene/core/types.py
+++ b/graphene/core/types.py
@@ -83,6 +83,13 @@ class ObjectTypeMeta(type):
 
 
 class ObjectType(six.with_metaclass(ObjectTypeMeta)):
+    def __new__(cls, instance=None, *args, **kwargs):
+        if cls._meta.interface:
+            raise Exception("An interface cannot be initialized")
+        if instance == None:
+            return None
+        return super(ObjectType, cls).__new__(cls, instance, *args, **kwargs)
+
     def __init__(self, instance=None):
         signals.pre_init.send(self.__class__, instance=instance)
         self.instance = instance
@@ -136,6 +143,7 @@ class Interface(ObjectType):
         interface = True
         proxy = True
 
+
 @signals.init_schema.connect
 def add_types_to_schema(schema):
     own_schema = schema
diff --git a/tests/starwars_relay/schema.py b/tests/starwars_relay/schema.py
index fbbfc49c..8731f712 100644
--- a/tests/starwars_relay/schema.py
+++ b/tests/starwars_relay/schema.py
@@ -14,9 +14,7 @@ class Ship(relay.Node):
 
     @classmethod
     def get_node(cls, id):
-        ship = getShip(id)
-        if ship:
-            return Ship(ship)
+        return Ship(getShip(id))
 
 
 class Faction(relay.Node):
@@ -30,9 +28,7 @@ class Faction(relay.Node):
 
     @classmethod
     def get_node(cls, id):
-        faction = getFaction(id)
-        if faction:
-            return Faction(faction)
+        return Faction(getFaction(id))
 
 
 class Query(graphene.ObjectType):