add "null" to the error code enum of non_field_errors validation …

…errors since the error code is returned when submitting a post/patch/put with `null` as the request body (see #74 for details)

docs/changelog.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - enforce support of only drf-spectacular 0.27 and newer in pyproject.toml
 - ensure examples from `@extend_schema_serializer` are not ignored when adding error response examples
 - show default error response examples only when the corresponding status code is allowed
+- add `"null"` to the error code enum of `non_field_errors` validation errors
 
 ## [0.13.0] - 2024-02-28
 ### Changed

drf_standardized_errors/openapi_utils.py

@@ -205,7 +205,7 @@ def get_serializer_field_error_codes(field: serializers.Field, attr: str) -> Set
     # for top-level (as opposed to nested) serializer non_field_errors,
     # "required" and "null" errors are not raised
     if attr == drf_settings.NON_FIELD_ERRORS_KEY:
-        error_codes = set(error_codes).difference(["required", "null"])
+        error_codes = set(error_codes).difference(["required"])
 
     # for ManyRelatedFields, add the error codes from the child_relation
     # to the parent error codes. That's because DRF raises child_relation

tests/test_openapi.py

@@ -216,12 +216,17 @@ def test_error_codes_for_polymorphic_serializer():
     create_error_codes = schema["components"]["schemas"][
         "ValidateCreateNonFieldErrorsErrorComponent"
     ]["properties"]["code"]["enum"]
-    assert set(create_error_codes) == {"invalid", "object1_code", "object2_code"}
+    assert set(create_error_codes) == {
+        "invalid",
+        "null",
+        "object1_code",
+        "object2_code",
+    }
 
     patch_error_codes = schema["components"]["schemas"][
         "ValidatePartialUpdateNonFieldErrorsErrorComponent"
     ]["properties"]["code"]["enum"]
-    assert set(patch_error_codes) == {"invalid", "object1_code", "object2_code"}
+    assert set(patch_error_codes) == {"invalid", "null", "object1_code", "object2_code"}
 
 
 class CustomFilterSet(FilterSet):

tests/test_openapi_utils.py

@@ -298,7 +298,7 @@ def serializer():
 def test_top_level_non_field_errors_error_codes(serializer):
     """required and null should NOT be listed as error codes"""
     (field,) = get_serializer_fields_with_error_codes([serializer])
-    assert field.error_codes == {"invalid"}
+    assert field.error_codes == {"invalid", "null"}
 
 
 @pytest.fixture