id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 36786 XML serializer mishandles nullable elements of a related object's natural key Jacob Walls Youngkwang Yang "If a field on your model's natural key is nullable, a dumpdata/loaddata roundtrip works in JSON but fails in XML because the XML fixture contains `None`, which deserializes to `""None""`, which is != `None`. Elsewhere there is an `addQuickElement(""None"")` that produces a clear `` value, but nothing like that is used for nullable elements of a natural key. ---- models {{{#!py from django.db import models class WidgetManager(models.Manager): def get_by_natural_key(self, name, foo): return self.get(name=name, foo=foo) class Widget(models.Model): name = models.CharField(default=""default"") foo = models.UUIDField(null=True) objects = WidgetManager() def natural_key(self): return (self.name, self.foo) class Gadget(models.Model): widget = models.ForeignKey(Widget, on_delete=models.CASCADE, null=True) }}} {{{ ./manage.py makemigrations ./manage.py migrate ./manage.py shell }}} {{{#!py Gadget.objects.create(widget=Widget.objects.create()) }}} {{{ ./manage.py dumpdata myapp --format=xml --natural-foreign > fixture.xml ./manage.py loaddata fixture.xml }}} Fixture content: {{{#!xml default default None }}} loaddata error: {{{#!py Traceback (most recent call last): File ""/Users/jwalls/django/django/db/models/fields/__init__.py"", line 2766, in to_python return uuid.UUID(**{input_form: value}) ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^ File ""/Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/uuid.py"", line 219, in __init__ raise ValueError('badly formed hexadecimal UUID string') ValueError: badly formed hexadecimal UUID string During handling of the above exception, another exception occurred: Traceback (most recent call last): File ""/Users/jwalls/zed/./manage.py"", line 22, in main() ~~~~^^ File ""/Users/jwalls/zed/./manage.py"", line 18, in main execute_from_command_line(sys.argv) ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^ File ""/Users/jwalls/django/django/core/management/__init__.py"", line 443, in execute_from_command_line utility.execute() ~~~~~~~~~~~~~~~^^ File ""/Users/jwalls/django/django/core/management/__init__.py"", line 437, in execute self.fetch_command(subcommand).run_from_argv(self.argv) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^ File ""/Users/jwalls/django/django/core/management/base.py"", line 416, in run_from_argv self.execute(*args, **cmd_options) ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/core/management/base.py"", line 460, in execute output = self.handle(*args, **options) File ""/Users/jwalls/django/django/core/management/commands/loaddata.py"", line 103, in handle self.loaddata(fixture_labels) ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/core/management/commands/loaddata.py"", line 164, in loaddata self.load_label(fixture_label) ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/core/management/commands/loaddata.py"", line 252, in load_label for obj in objects: ^^^^^^^ File ""/Users/jwalls/django/django/core/serializers/xml_serializer.py"", line 235, in __next__ return self._handle_object(node) ~~~~~~~~~~~~~~~~~~~^^^^^^ File ""/Users/jwalls/django/django/core/serializers/xml_serializer.py"", line 293, in _handle_object value = self._handle_fk_field_node(field_node, field) File ""/Users/jwalls/django/django/core/serializers/xml_serializer.py"", line 332, in _handle_fk_field_node obj = model._default_manager.db_manager( self.db ).get_by_natural_key(*field_value) File ""/Users/jwalls/zed/myapp/models.py"", line 6, in get_by_natural_key return self.get(name=name, foo=foo) ~~~~~~~~^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/manager.py"", line 87, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/query.py"", line 625, in get clone = self._chain() if self.query.combinator else self.filter(*args, **kwargs) ~~~~~~~~~~~^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/query.py"", line 1542, in filter return self._filter_or_exclude(False, args, kwargs) ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/query.py"", line 1560, in _filter_or_exclude clone._filter_or_exclude_inplace(negate, args, kwargs) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/query.py"", line 1570, in _filter_or_exclude_inplace self._query.add_q(Q(*args, **kwargs)) ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/sql/query.py"", line 1671, in add_q clause, _ = self._add_q(q_object, can_reuse) ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/sql/query.py"", line 1703, in _add_q child_clause, needed_inner = self.build_filter( ~~~~~~~~~~~~~~~~~^ child, ^^^^^^ ...<7 lines>... update_join_types=update_join_types, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ) ^ File ""/Users/jwalls/django/django/db/models/sql/query.py"", line 1613, in build_filter condition = self.build_lookup(lookups, col, value) File ""/Users/jwalls/django/django/db/models/sql/query.py"", line 1440, in build_lookup lookup = lookup_class(lhs, rhs) File ""/Users/jwalls/django/django/db/models/lookups.py"", line 35, in __init__ self.rhs = self.get_prep_lookup() ~~~~~~~~~~~~~~~~~~~~^^ File ""/Users/jwalls/django/django/db/models/lookups.py"", line 391, in get_prep_lookup return super().get_prep_lookup() ~~~~~~~~~~~~~~~~~~~~~~~^^ File ""/Users/jwalls/django/django/db/models/lookups.py"", line 93, in get_prep_lookup return self.lhs.output_field.get_prep_value(self.rhs) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^ File ""/Users/jwalls/django/django/db/models/fields/__init__.py"", line 2750, in get_prep_value return self.to_python(value) ~~~~~~~~~~~~~~^^^^^^^ File ""/Users/jwalls/django/django/db/models/fields/__init__.py"", line 2768, in to_python raise exceptions.ValidationError( ...<3 lines>... ) django.core.exceptions.ValidationError: ['“None” is not a valid UUID.'] }}} " Bug closed Core (Serialization) 5.2 Normal fixed xml Youngkwang Yang Ready for checkin 1 0 0 0 0 0