From b474010060cba077af65d0a6dfe50f9a1cd09ad1 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Tue, 10 Nov 2015 11:54:20 -0800
Subject: [PATCH] Added LazyType

---
 graphene/core/schema.py                 |  3 +--
 graphene/core/types/base.py             |  9 +++++++++
 graphene/core/types/field.py            |  5 ++++-
 graphene/core/types/tests/test_field.py | 20 ++++++++++++++++++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/graphene/core/schema.py b/graphene/core/schema.py
index 66184b61..baf46d59 100644
--- a/graphene/core/schema.py
+++ b/graphene/core/schema.py
@@ -36,8 +36,7 @@ class Schema(object):
     def T(self, object_type):
         if not object_type:
             return
-        # if inspect.isclass(object_type) and issubclass(object_type, BaseType):
-        if True:
+        if inspect.isclass(object_type) and issubclass(object_type, BaseType) or isinstance(object_type, BaseType):
             if object_type not in self._types:
                 internal_type = object_type.internal_type(self)
                 self._types[object_type] = internal_type
diff --git a/graphene/core/types/base.py b/graphene/core/types/base.py
index e1ca98ae..cc8d4e20 100644
--- a/graphene/core/types/base.py
+++ b/graphene/core/types/base.py
@@ -7,6 +7,15 @@ class BaseType(object):
         return getattr(cls, 'T', None)
 
 
+class LazyType(BaseType):
+    def __init__(self, type_str):
+        self.type_str = type_str
+
+    def internal_type(self, schema):
+        type = schema.get_type(self.type_str)
+        return schema.T(type)
+
+
 @total_ordering
 class OrderedType(BaseType):
     creation_counter = 0
diff --git a/graphene/core/types/field.py b/graphene/core/types/field.py
index 5e03e2d0..d6367b5f 100644
--- a/graphene/core/types/field.py
+++ b/graphene/core/types/field.py
@@ -1,9 +1,10 @@
+import six
 from collections import OrderedDict
 from functools import wraps
 
 from graphql.core.type import GraphQLField, GraphQLInputObjectField
 
-from .base import OrderedType
+from .base import LazyType, OrderedType
 from .argument import to_arguments
 from ...utils import to_camel_case
 from ..types import BaseObjectType, InputObjectType
@@ -18,6 +19,8 @@ class Field(OrderedType):
         _creation_counter = kwargs.pop('_creation_counter', None)
         super(Field, self).__init__(_creation_counter=_creation_counter)
         self.name = name
+        if isinstance(type, six.string_types) and type != 'self':
+            type = LazyType(type)
         self.type = type
         self.description = description
         args = OrderedDict(args or {}, **kwargs)
diff --git a/graphene/core/types/tests/test_field.py b/graphene/core/types/tests/test_field.py
index 449f52a3..5f8042d5 100644
--- a/graphene/core/types/tests/test_field.py
+++ b/graphene/core/types/tests/test_field.py
@@ -2,6 +2,7 @@ from graphql.core.type import GraphQLField, GraphQLInputObjectField, GraphQLStri
 
 from ..field import Field, InputField
 from ..scalars import String
+from ..base import LazyType
 from graphene.core.types import ObjectType, InputObjectType
 from graphene.core.schema import Schema
 
@@ -52,6 +53,25 @@ def test_field_custom_name():
     assert field.attname == 'my_field'
 
 
+def test_field_self():
+    field = Field('self', name='my_customName')
+
+    class MyObjectType(ObjectType):
+        my_field = field
+
+    assert field.type == MyObjectType
+
+
+def test_field_string_reference():
+    field = Field('MyObjectType', name='my_customName')
+
+    class MyObjectType(ObjectType):
+        my_field = field
+
+    assert isinstance(field.type, LazyType)
+    assert field.type.type_str == 'MyObjectType'
+
+
 def test_field_custom_arguments():
     field = Field(None, name='my_customName', p=String())