From 2d557d6ed729063834dd3c6b39c6584e8a183ab2 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Tue, 11 Jul 2017 21:16:41 -0700
Subject: [PATCH] Simplified mutation

---
 graphene/types/mutation.py   | 79 ++++++++++++++++++++++++------------
 graphene/types/objecttype.py |  5 ++-
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/graphene/types/mutation.py b/graphene/types/mutation.py
index 2e8e120aa..4b662f0d6 100644
--- a/graphene/types/mutation.py
+++ b/graphene/types/mutation.py
@@ -1,33 +1,58 @@
-from functools import partial
+from collections import OrderedDict
 
-import six
-
-from ..utils.is_base_type import is_base_type
 from ..utils.get_unbound_function import get_unbound_function
 from ..utils.props import props
 from .field import Field
-from .objecttype import ObjectType, ObjectTypeMeta
-
-
-class MutationMeta(ObjectTypeMeta):
-    def __new__(cls, name, bases, attrs):
-        # Also ensure initialization is only performed for subclasses of
-        # Mutation
-        if not is_base_type(bases, MutationMeta):
-            return type.__new__(cls, name, bases, attrs)
-
-        input_class = attrs.pop('Input', None)
-
-        cls = ObjectTypeMeta.__new__(cls, name, bases, attrs)
-        field_args = props(input_class) if input_class else {}
-        output_class = getattr(cls, 'Output', cls)
-        resolver = getattr(cls, 'mutate', None)
+from .utils import yank_fields_from_attrs
+from .objecttype import ObjectType, ObjectTypeOptions
+
+from .base import BaseOptions, BaseType
+
+
+class MutationOptions(ObjectTypeOptions):
+    arguments = None  # type: Dict[str, Argument]
+    output = None  # type: Type[ObjectType]
+    resolver = None  # type: Function
+
+
+class Mutation(ObjectType):
+    '''
+    Mutation Type Definition
+    '''
+    @classmethod
+    def __init_subclass_with_meta__(cls, resolver=None, output=None, arguments=None, **options):
+        _meta = MutationOptions(cls)
+
+        output = output or getattr(cls, 'Output', None)
+        fields = {}
+        if not output:
+            # If output is defined, we don't need to get the fields
+            fields = OrderedDict()
+            for base in reversed(cls.__mro__):
+                fields.update(
+                    yank_fields_from_attrs(base.__dict__, _as=Field)
+                )
+            output = cls
+        
+        if not arguments:
+            input_class = getattr(cls, 'Input', None)
+            if input_class:
+                arguments = props(input_class)
+            else:
+                arguments = {}
+
+        resolver = resolver or get_unbound_function(getattr(cls, 'mutate', None))
         assert resolver, 'All mutations must define a mutate method in it'
-        resolver = get_unbound_function(resolver)
-        cls.Field = partial(
-            Field, output_class, args=field_args, resolver=resolver)
-        return cls
-
 
-class Mutation(six.with_metaclass(MutationMeta, ObjectType)):
-    pass
+        _meta.fields = fields
+        _meta.output = output
+        _meta.resolver = resolver
+        _meta.arguments = arguments
+
+        super(Mutation, cls).__init_subclass_with_meta__(_meta=_meta, **options)
+    
+    @classmethod
+    def Field(cls, *args, **kwargs):
+        return Field(
+            cls._meta.output, args=cls._meta.arguments, resolver=cls._meta.resolver
+        )
diff --git a/graphene/types/objecttype.py b/graphene/types/objecttype.py
index ac591e058..e641867a5 100644
--- a/graphene/types/objecttype.py
+++ b/graphene/types/objecttype.py
@@ -23,8 +23,9 @@ class ObjectType(BaseType):
     have a name, but most importantly describe their fields.
     '''
     @classmethod
-    def __init_subclass_with_meta__(cls, interfaces=(), possible_types=(), default_resolver=None, **options):
-        _meta = ObjectTypeOptions(cls)
+    def __init_subclass_with_meta__(cls, interfaces=(), possible_types=(), default_resolver=None, _meta=None, **options):
+        if not _meta:
+            _meta = ObjectTypeOptions(cls)
 
         fields = OrderedDict()