From d7bb1eaa350a1f38599f481540225cb26078162e Mon Sep 17 00:00:00 2001
From: Denis Orehovsky <denis.orehovsky@gmail.com>
Date: Wed, 30 Sep 2020 08:39:18 +0300
Subject: [PATCH] Partial serializer should not have required fields

---
 rest_framework/schemas/openapi.py |  2 +-
 tests/schemas/test_openapi.py     | 50 +++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/rest_framework/schemas/openapi.py b/rest_framework/schemas/openapi.py
index 8a8e267e0f..a7fd91c2ec 100644
--- a/rest_framework/schemas/openapi.py
+++ b/rest_framework/schemas/openapi.py
@@ -515,7 +515,7 @@ def map_serializer(self, serializer):
             if isinstance(field, serializers.HiddenField):
                 continue
 
-            if field.required:
+            if field.required and not serializer.partial:
                 required.append(field.field_name)
 
             schema = self.map_field(field)
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
index 8ea910dc1e..b8ca241107 100644
--- a/tests/schemas/test_openapi.py
+++ b/tests/schemas/test_openapi.py
@@ -349,6 +349,56 @@ class View(generics.GenericAPIView):
         assert list(schema['properties']['nested']['properties'].keys()) == ['number']
         assert schema['properties']['nested']['required'] == ['number']
 
+    def test_response_body_partial_serializer(self):
+        path = '/'
+        method = 'GET'
+
+        class ItemSerializer(serializers.Serializer):
+            text = serializers.CharField()
+
+            def __init__(self, *args, **kwargs):
+                super().__init__(*args, **kwargs)
+                self.partial = True
+
+        class View(generics.GenericAPIView):
+            serializer_class = ItemSerializer
+
+        view = create_view(
+            View,
+            method,
+            create_request(path),
+        )
+        inspector = AutoSchema()
+        inspector.view = view
+
+        responses = inspector.get_responses(path, method)
+        assert responses == {
+            '200': {
+                'description': '',
+                'content': {
+                    'application/json': {
+                        'schema': {
+                            'type': 'array',
+                            'items': {
+                                '$ref': '#/components/schemas/Item'
+                            },
+                        },
+                    },
+                },
+            },
+        }
+        components = inspector.get_components(path, method)
+        assert components == {
+            'Item': {
+                'type': 'object',
+                'properties': {
+                    'text': {
+                        'type': 'string',
+                    },
+                },
+            }
+        }
+
     def test_list_response_body_generation(self):
         """Test that an array schema is returned for list views."""
         path = '/'