From a8584febade36344386ee06dfdeffb1750677564 Mon Sep 17 00:00:00 2001
From: Jonathan Kim <jkimbo@gmail.com>
Date: Tue, 25 Jun 2019 16:55:34 +0100
Subject: [PATCH] Add some checking around fields and exclude definitions

---
 graphene_django/tests/test_types.py | 28 ++++++++++++++++++++++++++++
 graphene_django/types.py            | 15 +++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/graphene_django/tests/test_types.py b/graphene_django/tests/test_types.py
index 06a9e3d..0cd0740 100644
--- a/graphene_django/tests/test_types.py
+++ b/graphene_django/tests/test_types.py
@@ -275,6 +275,34 @@ def test_django_objecttype_exclude_fields_and_exclude():
                 exclude_fields = ["email"]
 
 
+@with_local_registry
+def test_django_objecttype_exclude_and_only():
+    with pytest.raises(AssertionError):
+
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                exclude = ["email"]
+                fields = ["id"]
+
+
+@with_local_registry
+def test_django_objecttype_fields_exclude_type_checking():
+    with pytest.raises(TypeError):
+
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = "foo"
+
+    with pytest.raises(TypeError):
+
+        class Reporter2(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = "foo"
+
+
 class TestDjangoObjectType:
     @pytest.fixture
     def PetModel(self):
diff --git a/graphene_django/types.py b/graphene_django/types.py
index 1492f38..145e9a9 100644
--- a/graphene_django/types.py
+++ b/graphene_django/types.py
@@ -111,17 +111,32 @@ class DjangoObjectType(ObjectType):
                 )
             )
 
+        assert not (fields and exclude), (
+            "Cannot set both 'fields' and 'exclude' options on "
+            "DjangoObjectType {class_name}.".format(class_name=cls.__name__)
+        )
+
         # Alias only_fields -> fields
         if only_fields and fields:
             raise Exception("Can't set both only_fields and fields")
         if only_fields:
             fields = only_fields
+        if fields and not isinstance(fields, (list, tuple)):
+            raise TypeError(
+                'The `fields` option must be a list or tuple or "__all__". '
+                "Got %s." % type(fields).__name__
+            )
 
         # Alias exclude_fields -> exclude
         if exclude_fields and exclude:
             raise Exception("Can't set both exclude_fields and exclude")
         if exclude_fields:
             exclude = exclude_fields
+        if exclude and not isinstance(exclude, (list, tuple)):
+            raise TypeError(
+                "The `exclude` option must be a list or tuple. Got %s."
+                % type(exclude).__name__
+            )
 
         django_fields = yank_fields_from_attrs(
             construct_fields(model, registry, fields, exclude, convert_choices_to_enum),