Use default value only for special fields like timestamp, uuid

model_clone/mixins/clone.py

@@ -321,12 +321,11 @@ def _create_copy_of_instance(instance, using=None, force=False, sub_clone=False)
         new_instance = cls()
 
         for f in fields:
-            value = f.get_default() or getattr(instance, f.attname, None)
+            if not f.editable:
+                f.pre_save(new_instance, add=True)
+                continue
 
-            if isinstance(f, (models.DateTimeField, models.DateField)):
-                if f.auto_now or f.auto_now_add:
-                    f.pre_save(new_instance, add=True)
-                    continue
+            value = getattr(instance, f.attname)
 
             if all(
                 [

model_clone/tests/test_clone_mixin.py

@@ -62,12 +62,13 @@ def test_cloning_model_with_custom_id(self):
         clone = instance.make_clone({"user": self.user2})
         self.assertNotEqual(instance.pk, clone.pk)
 
-    @patch("sample.models.Book._clone_excluded_fields", new_callable=PropertyMock)
+    @patch("sample.models.Library._clone_excluded_fields", new_callable=PropertyMock)
     def test_cloning_model_with_excluded_fields(self, _clone_excluded_fields_mock):
         _clone_excluded_fields_mock.return_value = ["name"]
         instance = Library.objects.create(name="First library", user=self.user1)
         clone = instance.make_clone({"name": "New Library"})
         self.assertNotEqual(instance.pk, clone.pk)
+        self.assertNotEqual(instance.name, clone.name)
 
     def test_cloning_explict_fields(self):
         name = "New Library"
@@ -78,6 +79,25 @@ def test_cloning_explict_fields(self):
         self.assertNotEqual(instance.pk, clone.pk)
         self.assertNotEqual(instance.name, clone.name)
 
+    @patch("sample.models.Book._clone_fields", new_callable=PropertyMock)
+    def test_cloning_with_default_value(self, _clone_fields_mock):
+        instance = Book.objects.create(
+            name="Not Published Book", created_by=self.user1, published_at=None
+        )
+        _clone_fields_mock.return_value = ["name", "created_by", "slug", "published_at"]
+        clone = instance.make_clone()
+        self.assertNotEqual(instance.pk, clone.pk)
+        self.assertEqual(instance.name, clone.name)
+        self.assertNotEqual(instance.slug, clone.slug)
+        self.assertIsNone(clone.published_at)
+
+        _clone_fields_mock.return_value.remove("published_at")
+        clone = instance.make_clone()
+        self.assertNotEqual(instance.pk, clone.pk)
+        self.assertEqual(instance.name, clone.name)
+        self.assertNotEqual(instance.slug, clone.slug)
+        self.assertIsNotNone(clone.published_at)
+
     def test_cloning_unique_fk_field(self):
         name = "New Library"
         instance = Library.objects.create(name=name, user=self.user1)

sample/migrations/0018_auto_20210628_2301.py

@@ -0,0 +1,33 @@
+# Generated by Django 3.1.8 on 2021-06-28 23:01
+
+from django.db import migrations, models
+from django.utils import timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("sample", "0017_auto_20210624_1117"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="author",
+            name="last_name",
+            field=models.CharField(blank=True, default="Unknown", max_length=200),
+        ),
+        migrations.AlterField(
+            model_name="author",
+            name="sex",
+            field=models.CharField(
+                choices=[("U", "Unknown"), ("F", "Female"), ("M", "Male")],
+                default="U",
+                max_length=1,
+            ),
+        ),
+        migrations.AddField(
+            model_name="book",
+            name="published_at",
+            field=models.DateTimeField(blank=True, default=timezone.now, null=True),
+        ),
+    ]

sample/models.py

@@ -11,16 +11,17 @@
 
 class Author(CloneModel):
     first_name = models.CharField(max_length=200, blank=True, unique=True)
-    last_name = models.CharField(max_length=200, blank=True)
+    last_name = models.CharField(default="Unknown", max_length=200, blank=True)
     age = models.PositiveIntegerField()
 
     uuid = models.UUIDField(default=uuid4, unique=True, editable=False)
 
     SEX_CHOICES = [
+        ("U", "Unknown"),
         ("F", "Female"),
         ("M", "Male"),
     ]
-    sex = models.CharField(choices=SEX_CHOICES, max_length=1)
+    sex = models.CharField(choices=SEX_CHOICES, max_length=1, default="U")
     created_by = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         on_delete=models.PROTECT,
@@ -62,6 +63,7 @@ class Book(CloneModel):
     created_at = models.DateTimeField(auto_now_add=True)
     tags = models.ManyToManyField(Tag, through="BookTag")
     sale_tags = models.ManyToManyField(SaleTag, through="BookSaleTag")
+    published_at = models.DateTimeField(null=True, blank=True, default=timezone.now)
 
     def __str__(self):
         return _(self.name)