Fix error of multiple inputs with the same type. When using same seri…

graphene_django/rest_framework/serializer_converter.py

@@ -57,18 +57,25 @@ def convert_serializer_field(field, is_input=True):
 
 
 def convert_serializer_to_input_type(serializer_class):
+    cached_type = convert_serializer_to_input_type.cache.get(serializer_class.__name__, None)
+    if cached_type:
+        return cached_type
     serializer = serializer_class()
 
     items = {
         name: convert_serializer_field(field)
         for name, field in serializer.fields.items()
     }
-
-    return type(
+    ret_type = type(
         "{}Input".format(serializer.__class__.__name__),
         (graphene.InputObjectType,),
         items,
     )
+    convert_serializer_to_input_type.cache[serializer_class.__name__] = ret_type
+    return ret_type
+
+
+convert_serializer_to_input_type.cache = {}
 
 
 @get_graphene_type_from_serializer_field.register(serializers.Field)

graphene_django/rest_framework/tests/test_multiple_model_serializers.py

@@ -0,0 +1,63 @@
+import graphene
+import pytest
+from django.db import models
+from graphene import Schema
+from rest_framework import serializers
+
+from graphene_django import DjangoObjectType
+from graphene_django.rest_framework.mutation import SerializerMutation
+
+pytestmark = pytest.mark.django_db
+
+
+class MyFakeChildModel(models.Model):
+    name = models.CharField(max_length=50)
+    created = models.DateTimeField(auto_now_add=True)
+
+
+class MyFakeParentModel(models.Model):
+    name = models.CharField(max_length=50)
+    created = models.DateTimeField(auto_now_add=True)
+    child1 = models.OneToOneField(MyFakeChildModel, related_name='parent1', on_delete=models.CASCADE)
+    child2 = models.OneToOneField(MyFakeChildModel, related_name='parent2', on_delete=models.CASCADE)
+
+
+class ParentType(DjangoObjectType):
+    class Meta:
+        model = MyFakeParentModel
+        interfaces = (graphene.relay.Node,)
+
+
+class ChildType(DjangoObjectType):
+    class Meta:
+        model = MyFakeChildModel
+        interfaces = (graphene.relay.Node,)
+
+
+class MyModelChildSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = MyFakeChildModel
+        fields = "__all__"
+
+
+class MyModelParentSerializer(serializers.ModelSerializer):
+    child1 = MyModelChildSerializer()
+    child2 = MyModelChildSerializer()
+
+    class Meta:
+        model = MyFakeParentModel
+        fields = "__all__"
+
+
+class MyParentModelMutation(SerializerMutation):
+    class Meta:
+        serializer_class = MyModelParentSerializer
+
+
+class Mutation(graphene.ObjectType):
+    createParentWithChild = MyParentModelMutation.Field()
+
+
+def test_create_schema():
+    schema = Schema(mutation=Mutation, types=[ParentType, ChildType])
+    assert schema