From b772499b9b9f4878420ad7c91515f2c45ea1e0d2 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Sun, 19 Jun 2016 14:29:41 -0700
Subject: [PATCH] Improved Interface/ObjectType is_type_of abstraction

---
 graphene/types/interface.py  | 20 ++++++++++++-------
 graphene/types/objecttype.py | 37 ++++++++++++++++++++----------------
 2 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/graphene/types/interface.py b/graphene/types/interface.py
index 190d9f66..37218d8c 100644
--- a/graphene/types/interface.py
+++ b/graphene/types/interface.py
@@ -16,6 +16,16 @@ class GrapheneInterfaceType(GrapheneGraphQLType, GraphQLInterfaceType):
 
 class InterfaceTypeMeta(type):
 
+    @staticmethod
+    def _get_interface_options(meta):
+        return Options(
+            meta,
+            name=None,
+            description=None,
+            graphql_type=None,
+            abstract=False
+        )
+
     def __new__(cls, name, bases, attrs):
         super_new = super(InterfaceTypeMeta, cls).__new__
 
@@ -24,13 +34,7 @@ class InterfaceTypeMeta(type):
         if not is_base_type(bases, InterfaceTypeMeta):
             return super_new(cls, name, bases, attrs)
 
-        options = Options(
-            attrs.pop('Meta', None),
-            name=None,
-            description=None,
-            graphql_type=None,
-            abstract=False
-        )
+        options = cls._get_interface_options(attrs.pop('Meta', None))
 
         fields = get_fields(Interface, attrs, bases)
         attrs = attrs_without_fields(attrs, fields)
@@ -41,6 +45,7 @@ class InterfaceTypeMeta(type):
             options.graphql_type = GrapheneInterfaceType(
                 graphene_type=cls,
                 name=options.name or cls.__name__,
+                resolve_type=cls.resolve_type,
                 description=options.description or cls.__doc__,
                 fields=fields,
             )
@@ -59,6 +64,7 @@ def attrs_without_fields(attrs, fields):
 
 
 class Interface(six.with_metaclass(InterfaceTypeMeta)):
+    resolve_type = None
 
     def __init__(self, *args, **kwargs):
         from .objecttype import ObjectType
diff --git a/graphene/types/objecttype.py b/graphene/types/objecttype.py
index e4518145..6892936b 100644
--- a/graphene/types/objecttype.py
+++ b/graphene/types/objecttype.py
@@ -26,22 +26,6 @@ class GrapheneObjectType(GrapheneGraphQLType, GraphQLObjectType):
             if isinstance(interface, GrapheneInterfaceType):
                 interface.graphene_type.implements(self.graphene_type)
 
-    @property
-    def is_type_of(self):
-        return self._is_type_of or self.default_is_type_of
-
-    @is_type_of.setter
-    def is_type_of(self, is_type_of):
-        self._is_type_of = is_type_of
-
-    def default_is_type_of(self, interface, context, info):
-        from ..utils.get_graphql_type import get_graphql_type
-        try:
-            graphql_type = get_graphql_type(type(interface))
-            return graphql_type.name == self.name
-        except:
-            return False
-
 
 def get_interfaces(interfaces):
     from ..utils.get_graphql_type import get_graphql_type
@@ -51,6 +35,13 @@ def get_interfaces(interfaces):
         yield graphql_type
 
 
+def is_objecttype(bases):
+    for base in bases:
+        if issubclass(base, ObjectType):
+            return True
+    return False
+
+
 # We inherit from InterfaceTypeMeta instead of type for being able
 # to have ObjectTypes extending Interfaces using Python syntax, like:
 # class MyObjectType(ObjectType, MyInterface)
@@ -61,9 +52,13 @@ class ObjectTypeMeta(InterfaceTypeMeta):
 
         # Also ensure initialization is only performed for subclasses of Model
         # (excluding Model class itself).
+
         if not is_base_type(bases, ObjectTypeMeta):
             return super_new(cls, name, bases, attrs)
 
+        if not is_objecttype(bases):
+            return super(ObjectTypeMeta, cls).__new__(cls, name, bases, attrs)
+
         options = Options(
             attrs.pop('Meta', None),
             name=None,
@@ -86,6 +81,7 @@ class ObjectTypeMeta(InterfaceTypeMeta):
                 name=options.name or cls.__name__,
                 description=options.description or cls.__doc__,
                 fields=fields,
+                is_type_of=cls.is_type_of,
                 interfaces=tuple(get_interfaces(interfaces + base_interfaces))
             )
         else:
@@ -147,3 +143,12 @@ class ObjectType(six.with_metaclass(ObjectTypeMeta)):
                 raise TypeError(
                     "'%s' is an invalid keyword argument for this function" %
                     list(kwargs)[0])
+
+    @classmethod
+    def is_type_of(cls, interface, context, info):
+        from ..utils.get_graphql_type import get_graphql_type
+        try:
+            graphql_type = get_graphql_type(type(interface))
+            return graphql_type.name == cls._meta.graphql_type.name
+        except:
+            return False