Fixed #28385 -- Fixed deserializing natural keys when primary key has a default value.

Co-Authored-By: Hasan Ramezani <hasan.r67@gmail.com>

django/core/serializers/base.py

@@ -256,15 +256,18 @@ def build_instance(Model, data, db):
     If the model instance doesn't have a primary key and the model supports
     natural keys, try to retrieve it from the database.
     """
-    obj = Model(**data)
-    if (obj.pk is None and hasattr(Model, 'natural_key') and
-            hasattr(Model._default_manager, 'get_by_natural_key')):
-        natural_key = obj.natural_key()
+    default_manager = Model._meta.default_manager
+    pk = data.get(Model._meta.pk.name)
+    if (pk is None and hasattr(default_manager, 'get_by_natural_key') and
+            hasattr(Model, 'natural_key')):
+        natural_key = Model(**data).natural_key()
         try:
-            obj.pk = Model._default_manager.db_manager(db).get_by_natural_key(*natural_key).pk
+            data[Model._meta.pk.attname] = Model._meta.pk.to_python(
+                default_manager.db_manager(db).get_by_natural_key(*natural_key).pk
+            )
         except Model.DoesNotExist:
             pass
-    return obj
+    return Model(**data)
 
 
 def deserialize_m2m_values(field, field_value, using, handle_forward_references):

tests/serializers/models/natural.py

@@ -1,4 +1,6 @@
 """Models for test_natural.py"""
+import uuid
+
 from django.db import models
 
 
@@ -37,3 +39,17 @@ class NaturalKeyThing(models.Model):
 
     def __str__(self):
         return self.key
+
+
+class NaturalPKWithDefault(models.Model):
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    name = models.CharField(max_length=100, unique=True)
+
+    class Manager(models.Manager):
+        def get_by_natural_key(self, name):
+            return self.get(name=name)
+
+    objects = Manager()
+
+    def natural_key(self):
+        return (self.name,)

tests/serializers/test_natural.py

@@ -2,7 +2,10 @@ from django.core import serializers
 from django.db import connection
 from django.test import TestCase
 
-from .models import Child, FKDataNaturalKey, NaturalKeyAnchor, NaturalKeyThing
+from .models import (
+    Child, FKDataNaturalKey, NaturalKeyAnchor, NaturalKeyThing,
+    NaturalPKWithDefault,
+)
 from .tests import register_tests
 
 
@@ -182,6 +185,21 @@ def forward_ref_m2m_with_error_test(self, format):
         obj.save_deferred_fields()
 
 
+def pk_with_default(self, format):
+    """
+    The deserializer works with natural keys when the primary key has a default
+    value.
+    """
+    obj = NaturalPKWithDefault.objects.create(name='name')
+    string_data = serializers.serialize(
+        format, NaturalPKWithDefault.objects.all(), use_natural_foreign_keys=True,
+        use_natural_primary_keys=True,
+    )
+    objs = list(serializers.deserialize(format, string_data))
+    self.assertEqual(len(objs), 1)
+    self.assertEqual(objs[0].object.pk, obj.pk)
+
+
 # Dynamically register tests for each serializer
 register_tests(NaturalKeySerializerTests, 'test_%s_natural_key_serializer', natural_key_serializer_test)
 register_tests(NaturalKeySerializerTests, 'test_%s_serializer_natural_keys', natural_key_test)
@@ -190,3 +208,4 @@ register_tests(NaturalKeySerializerTests, 'test_%s_forward_references_fks', forw
 register_tests(NaturalKeySerializerTests, 'test_%s_forward_references_fk_errors', forward_ref_fk_with_error_test)
 register_tests(NaturalKeySerializerTests, 'test_%s_forward_references_m2ms', forward_ref_m2m_test)
 register_tests(NaturalKeySerializerTests, 'test_%s_forward_references_m2m_errors', forward_ref_m2m_with_error_test)
+register_tests(NaturalKeySerializerTests, 'test_%s_pk_with_default', pk_with_default)