serialization_regrouping.py

from collections import OrderedDict
from typing import Dict, Any, Mapping

from django.core.exceptions import ValidationError as DjangoValidationError
from rest_framework import serializers
from rest_framework.fields import set_value, get_error_detail, SkipField
from rest_framework.exceptions import ValidationError
from rest_framework.settings import api_settings


class SetValueOverrideSerializerMixin(serializers.Serializer):
    """
    Copies serializers.Serializer.to_internal_value, making set_value overridable.
    No functional changes introduced when compared to serializers.Serializer.
    """

    def set_value(self, aggregator: Dict[str, Any], field: serializers.Field, validated_value: Any):
        set_value(aggregator, field.source_attrs, validated_value)

    def to_internal_value(self, data):
        """Original implementation, except for the comment-wrapped part below."""
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(datatype=type(data).__name__)
            raise ValidationError({api_settings.NON_FIELD_ERRORS_KEY: [message]}, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                ###########################################
                # NB: Beginning of the added functionality
                self.set_value(ret, field, validated_value)
                # NB: End of the added functionality
                ###########################################

        if errors:
            raise ValidationError(errors)

        return ret


class RegroupSerializerMixin(SetValueOverrideSerializerMixin):

    def set_value(self, aggregator: Dict[str, Any], field: serializers.Field, validated_value: Any):
        """
        Uses deep_update to update aggregator with the validated_value, in case it is a mapping.
        """
        if isinstance(validated_value, Mapping):
            materialized_dict = {}
            set_value(materialized_dict, field.source_attrs, validated_value)
            #https://stackoverflow.com/questions/3232943/update-value-of-a-nested-dictionary-of-varying-depth
            aggregator.update(deep_update(aggregator, materialized_dict))
        else:
            super().set_value(aggregator, field, validated_value)

That might count as a golden vote than 😅

it will actually take some time. see what I commented there.