Function as_serializer_error

rest_framework/serializers.py:314–349

Coerce validation exceptions into a standardized serialized error format. This function normalizes both Django's `ValidationError` and REST framework's `ValidationError` into a dictionary structure compatible with serializer `.errors`, ensuring all values are represented as lis

(exc)

def as_serializer_error(exc):
    """
    Coerce validation exceptions into a standardized serialized error format.

    This function normalizes both Django's `ValidationError` and REST
    framework's `ValidationError` into a dictionary structure compatible
    with serializer `.errors`, ensuring all values are represented as
    lists of error details.

    The returned structure conforms to the serializer error contract:
    - Field-specific errors are returned as '{field-name: [errors]}'
    - Non-field errors are returned under the 'NON_FIELD_ERRORS_KEY'
    """
    assert isinstance(exc, (ValidationError, DjangoValidationError))

    if isinstance(exc, DjangoValidationError):
        detail = get_error_detail(exc)
    else:
        detail = exc.detail

    if isinstance(detail, Mapping):
        # If errors may be a dict we use the standard {key: list of values}.
        # Here we ensure that all the values are *lists* of errors.
        return {
            key: value if isinstance(value, (list, Mapping)) else [value]
            for key, value in detail.items()
        }
    elif isinstance(detail, list):
        # Errors raised as a list are non-field errors.
        return {
            api_settings.NON_FIELD_ERRORS_KEY: detail
        }
    # Errors raised as a string are non-field errors.
    return {
        api_settings.NON_FIELD_ERRORS_KEY: [detail]
    }


class Serializer(BaseSerializer, metaclass=SerializerMetaclass):