From 1281c1338df27df529ff7f891d2f23f2993a3178 Mon Sep 17 00:00:00 2001
From: Rustam Ganeyev <rganeyev@gmail.com>
Date: Sat, 2 Jan 2021 04:36:50 +0000
Subject: [PATCH] Introduced optional_fields to SerializationMutation (#1080)

* added optional_field to SerializationMutation to forcefully mark some fields as optional

* added tests
---
 graphene_django/rest_framework/mutation.py    | 10 ++++++++-
 .../rest_framework/serializer_converter.py    |  9 ++++++--
 .../rest_framework/tests/test_mutation.py     | 21 ++++++++++++++++++-
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/graphene_django/rest_framework/mutation.py b/graphene_django/rest_framework/mutation.py
index 000b21e..9e2ae12 100644
--- a/graphene_django/rest_framework/mutation.py
+++ b/graphene_django/rest_framework/mutation.py
@@ -18,6 +18,7 @@ class SerializerMutationOptions(MutationOptions):
     model_class = None
     model_operations = ["create", "update"]
     serializer_class = None
+    optional_fields = ()
 
 
 def fields_for_serializer(
@@ -27,6 +28,7 @@ def fields_for_serializer(
     is_input=False,
     convert_choices_to_enum=True,
     lookup_field=None,
+    optional_fields=(),
 ):
     fields = OrderedDict()
     for name, field in serializer.fields.items():
@@ -44,9 +46,13 @@ def fields_for_serializer(
 
         if is_not_in_only or is_excluded:
             continue
+        is_optional = name in optional_fields
 
         fields[name] = convert_serializer_field(
-            field, is_input=is_input, convert_choices_to_enum=convert_choices_to_enum
+            field,
+            is_input=is_input,
+            convert_choices_to_enum=convert_choices_to_enum,
+            force_optional=is_optional,
         )
     return fields
 
@@ -70,6 +76,7 @@ class SerializerMutation(ClientIDMutation):
         exclude_fields=(),
         convert_choices_to_enum=True,
         _meta=None,
+        optional_fields=(),
         **options
     ):
 
@@ -95,6 +102,7 @@ class SerializerMutation(ClientIDMutation):
             is_input=True,
             convert_choices_to_enum=convert_choices_to_enum,
             lookup_field=lookup_field,
+            optional_fields=optional_fields,
         )
         output_fields = fields_for_serializer(
             serializer,
diff --git a/graphene_django/rest_framework/serializer_converter.py b/graphene_django/rest_framework/serializer_converter.py
index 82a113a..18f34b8 100644
--- a/graphene_django/rest_framework/serializer_converter.py
+++ b/graphene_django/rest_framework/serializer_converter.py
@@ -19,7 +19,9 @@ def get_graphene_type_from_serializer_field(field):
     )
 
 
-def convert_serializer_field(field, is_input=True, convert_choices_to_enum=True):
+def convert_serializer_field(
+    field, is_input=True, convert_choices_to_enum=True, force_optional=False
+):
     """
     Converts a django rest frameworks field to a graphql field
     and marks the field as required if we are creating an input type
@@ -32,7 +34,10 @@ def convert_serializer_field(field, is_input=True, convert_choices_to_enum=True)
         graphql_type = get_graphene_type_from_serializer_field(field)
 
     args = []
-    kwargs = {"description": field.help_text, "required": is_input and field.required}
+    kwargs = {
+        "description": field.help_text,
+        "required": is_input and field.required and not force_optional,
+    }
 
     # if it is a tuple or a list it means that we are returning
     # the graphql type and the child type
diff --git a/graphene_django/rest_framework/tests/test_mutation.py b/graphene_django/rest_framework/tests/test_mutation.py
index ffbc4b5..5c2518d 100644
--- a/graphene_django/rest_framework/tests/test_mutation.py
+++ b/graphene_django/rest_framework/tests/test_mutation.py
@@ -3,7 +3,7 @@ import datetime
 from py.test import raises
 from rest_framework import serializers
 
-from graphene import Field, ResolveInfo
+from graphene import Field, ResolveInfo, NonNull, String
 from graphene.types.inputobjecttype import InputObjectType
 
 from ...types import DjangoObjectType
@@ -98,6 +98,25 @@ def test_exclude_fields():
     assert "created" not in MyMutation.Input._meta.fields
 
 
+def test_model_serializer_required_fields():
+    class MyMutation(SerializerMutation):
+        class Meta:
+            serializer_class = MyModelSerializer
+
+    assert "cool_name" in MyMutation.Input._meta.fields
+    assert MyMutation.Input._meta.fields["cool_name"].type == NonNull(String)
+
+
+def test_model_serializer_optional_fields():
+    class MyMutation(SerializerMutation):
+        class Meta:
+            serializer_class = MyModelSerializer
+            optional_fields = ("cool_name",)
+
+    assert "cool_name" in MyMutation.Input._meta.fields
+    assert MyMutation.Input._meta.fields["cool_name"].type == String
+
+
 def test_write_only_field():
     class WriteOnlyFieldModelSerializer(serializers.ModelSerializer):
         password = serializers.CharField(write_only=True)