determine error codes for validation errors only when the request serializer is indeed a serializer and not a basic type set using extend_schema (fixes #20)

Author: ghazi-git

docs/changelog.md

@@ -5,6 +5,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [UNRELEASED]
+### Fixed
+- account for specifying the request serializer as a basic type using `@extend_schema(request=OpenApiTypes.STR)`
+when determining error codes for validation errors.
 
 ## [0.12.3] - 2022-11-13
 ### Added

drf_standardized_errors/openapi.py

@@ -1,3 +1,4 @@
+import inspect
 from typing import List, Optional, Type
 
 from drf_spectacular.drainage import warn
@@ -131,8 +132,13 @@ def _should_add_validation_error_response(self) -> bool:
          to override to accomplish that (maybe sth like
          isinstance(self.view, SomeViewSet) and checking self.method)
         """
-        has_request_body = self.method in ("PUT", "PATCH", "POST") and bool(
-            self.get_request_serializer()
+        request_serializer = self.get_request_serializer()
+        has_request_body = self.method in ("PUT", "PATCH", "POST") and (
+            isinstance(request_serializer, serializers.Field)
+            or (
+                inspect.isclass(request_serializer)
+                and issubclass(request_serializer, serializers.Field)
+            )
         )
 
         filter_backends = get_django_filter_backends(self.get_filter_backends())

tests/test_openapi.py

@@ -4,6 +4,8 @@
 from django_filters import CharFilter
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from drf_spectacular.generators import SchemaGenerator
+from drf_spectacular.types import OpenApiTypes
+from drf_spectacular.utils import extend_schema
 from rest_framework import serializers
 from rest_framework.authentication import BasicAuthentication
 from rest_framework.generics import GenericAPIView, ListAPIView
@@ -118,6 +120,27 @@ def test_no_validation_error_for_unsafe_method():
     assert "400" not in responses
 
 
+class OpenAPITypesView(GenericAPIView):
+    # ensure that 400 is not added due to the parser classes by using a parser
+    # that does not raise a ParseError which results in adding a 400 error response
+    parser_classes = [CustomParser]
+
+    @extend_schema(request=OpenApiTypes.OBJECT, responses={204: None})
+    def post(self, request, *args, **kwargs):
+        return Response(status=204)
+
+
+def test_no_error_raised_when_request_serializer_is_set_as_openapi_type():
+    route = "validate/"
+    view = OpenAPITypesView.as_view()
+    try:
+        generate_view_schema(route, view)
+    except Exception:
+        pytest.fail(
+            "Schema generation failed when using `@extend_schema(request.OpenApiTypes.OBJECT)`"
+        )
+
+
 class CustomFilterSet(FilterSet):
     first_name = CharFilter()