Resolved bug cloning models with UniqueConstraint. (#423)

* Resolved bug cloning models with UniqueConstraint.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fixed test.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fixed test.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fixed test.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fixed test.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Updated test.

* Updated test.

* Updated test.

* Update utils.py

* Update test_clone_mixin.py

* Update test_clone_mixin.py

* Update test_clone_mixin.py

* Update test_clone_mixin.py

* Update utils.py

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

django_clone/settings.py

@@ -47,7 +47,7 @@
     "sample_driver",
 ]
 
-if sys.version_info >= (3, 6):
+if sys.version_info >= (3, 6) and "--fix" in sys.argv:
     INSTALLED_APPS += ["migration_fixer"]
 
 

model_clone/mixins/clone.py

@@ -14,6 +14,7 @@
     clean_value,
     context_mutable_attribute,
     get_fields_and_unique_fields_from_cls,
+    get_unique_default,
     get_unique_value,
     transaction_autocommit,
 )
@@ -341,9 +342,26 @@ def _create_copy_of_instance(instance, using=None, force=False, sub_clone=False)
                     and not f.choices
                 ):
                     value = clean_value(value, unique_duplicate_suffix)
-                    if use_unique_duplicate_suffix:
+
+                    if f.has_default():
+                        value = f.get_default()
+
+                        if not callable(f.default):
+                            value = get_unique_default(
+                                model=cls,
+                                fname=f.attname,
+                                value=value,
+                                transform=(
+                                    slugify if isinstance(f, SlugField) else str
+                                ),
+                                suffix=unique_duplicate_suffix,
+                                max_length=f.max_length,
+                                max_attempts=max_unique_duplicate_query_attempts,
+                            )
+
+                    elif use_unique_duplicate_suffix:
                         value = get_unique_value(
-                            obj=instance,
+                            model=cls,
                             fname=f.attname,
                             value=value,
                             transform=(slugify if isinstance(f, SlugField) else str),

model_clone/tests/test_clone_mixin.py

@@ -233,6 +233,34 @@ def test_cloning_without_explicit_clone_m2m_fields(self):
             list(book_clone.authors.values_list("first_name", "last_name")),
         )
 
+    def test_cloning_with_unique_constraint_is_valid(self):
+        sale_tag = SaleTag.objects.create(name="test-sale-tag")
+        clone_sale_tag_1 = sale_tag.make_clone()
+
+        self.assertNotEqual(sale_tag.pk, clone_sale_tag_1.pk)
+        self.assertRegexpMatches(
+            clone_sale_tag_1.name,
+            r"{}\s[\d]".format(SaleTag.UNIQUE_DUPLICATE_SUFFIX),
+        )
+
+        clone_sale_tag_2 = clone_sale_tag_1.make_clone()
+
+        self.assertNotEqual(clone_sale_tag_1.pk, clone_sale_tag_2.pk)
+        self.assertRegexpMatches(
+            clone_sale_tag_2.name,
+            r"{}\s[\d]".format(SaleTag.UNIQUE_DUPLICATE_SUFFIX),
+        )
+
+    def test_cloning_with_unique_constraint_uses_field_default(self):
+        tag = Tag.objects.create(name="test-tag")
+        clone_tag = tag.make_clone()
+
+        self.assertNotEqual(tag.pk, clone_tag.pk)
+        self.assertRegexpMatches(
+            clone_tag.name,
+            r"\s[\d]",
+        )
+
     @patch("sample.models.Book._clone_m2m_fields", new_callable=PropertyMock)
     def test_cloning_with_explicit_clone_m2m_fields(
         self,
@@ -416,17 +444,51 @@ def test_cloning_unique_together_fields_with_enum_field(self):
             created_by=self.user1,
         )
 
-        author_clone = author.make_clone()
+        author_clone_1 = author.make_clone()
 
-        self.assertNotEqual(author.pk, author_clone.pk)
-        self.assertEqual(author.sex, author_clone.sex)
+        self.assertNotEqual(author.pk, author_clone_1.pk)
+        self.assertEqual(author.sex, author_clone_1.sex)
         self.assertEqual(
-            author_clone.first_name,
+            author_clone_1.first_name,
             "{} {} {}".format(first_name, Author.UNIQUE_DUPLICATE_SUFFIX, 1),
         )
         self.assertEqual(
-            author_clone.last_name,
-            "{} {} {}".format(last_name, Author.UNIQUE_DUPLICATE_SUFFIX, 1),
+            author_clone_1.last_name,
+            Author._meta.get_field("last_name").get_default(),
+        )
+
+        author_clone_2 = author.make_clone()
+
+        self.assertNotEqual(author.pk, author_clone_2.pk)
+        self.assertEqual(author.sex, author_clone_2.sex)
+        self.assertEqual(
+            author_clone_2.first_name,
+            "{} {} {}".format(first_name, Author.UNIQUE_DUPLICATE_SUFFIX, 2),
+        )
+        self.assertEqual(
+            author_clone_2.last_name,
+            "{} {} {}".format(
+                Author._meta.get_field("last_name").get_default(),
+                Author.UNIQUE_DUPLICATE_SUFFIX,
+                1,
+            ),
+        )
+
+        author_clone_3 = author.make_clone()
+
+        self.assertNotEqual(author.pk, author_clone_3.pk)
+        self.assertEqual(author.sex, author_clone_3.sex)
+        self.assertEqual(
+            author_clone_3.first_name,
+            "{} {} {}".format(first_name, Author.UNIQUE_DUPLICATE_SUFFIX, 3),
+        )
+        self.assertEqual(
+            author_clone_3.last_name,
+            "{} {} {}".format(
+                Author._meta.get_field("last_name").get_default(),
+                Author.UNIQUE_DUPLICATE_SUFFIX,
+                2,
+            ),
         )
 
     def test_cloning_unique_slug_field(self):

model_clone/utils.py

@@ -99,6 +99,25 @@ def create_copy_of_instance(
     return new_obj
 
 
+def unpack_unique_constraints(opts, only_fields=()):
+    """
+    Unpack unique constraint fields.
+
+    :param opts: Model options
+    :type opts: `django.db.models.options.Options`
+    :param only_fields: Fields that should be considered.
+    :type only_fields: `collections.Iterable`
+    :return: Flat list of fields.
+    """
+    fields = []
+    constraints = getattr(
+        opts, "total_unique_constraints", getattr(opts, "constraints", [])
+    )
+    for constraint in constraints:
+        fields.extend([f for f in constraint.fields if f in only_fields])
+    return fields
+
+
 def unpack_unique_together(opts, only_fields=()):
     """
     Unpack unique together fields.
@@ -163,7 +182,7 @@ def get_value(value, suffix, transform, max_length, index):
     Append a suffix to a string value and apply a pass directly to a
     transformation function.
     """
-    duplicate_suffix = " {} {}".format(suffix, index)
+    duplicate_suffix = " " + "{} {}".format(suffix, index).strip()
     total_length = len(value + duplicate_suffix)
 
     if max_length is not None and total_length > max_length:
@@ -189,12 +208,20 @@ def generate_value(value, suffix, transform, max_length, max_attempts):
     )
 
 
-def get_unique_value(obj, fname, value, transform, suffix, max_length, max_attempts):
+def get_unique_value(
+    model,
+    fname,
+    value="",
+    transform=lambda v: v,
+    suffix="",
+    max_length=None,
+    max_attempts=100,
+):
     """
     Generate a unique value using current value and query the model
     for existing objects with the new value.
     """
-    qs = obj.__class__._default_manager.all()
+    qs = model._default_manager.all()
     it = generate_value(value, suffix, transform, max_length, max_attempts)
 
     new = six.next(it)
@@ -251,10 +278,54 @@ def get_fields_and_unique_fields_from_cls(
         only_fields=[f.attname for f in fields],
     )
 
+    unique_constraint_field_names = unpack_unique_constraints(
+        opts=cls._meta,
+        only_fields=[f.attname for f in fields],
+    )
+
     unique_fields = [
         f.name
         for f in fields
-        if not f.auto_created and (f.unique or f.name in unique_field_names)
+        if not f.auto_created
+        and (
+            f.unique
+            or f.name in unique_field_names
+            or f.name in unique_constraint_field_names
+        )
     ]
 
     return fields, unique_fields
+
+
+def get_unique_default(
+    model,
+    fname,
+    value,
+    transform=lambda v: v,
+    suffix="",
+    max_length=None,
+    max_attempts=100,
+):
+    """Get a unique value using the value and adding a suffix if needed."""
+
+    qs = model._default_manager.all()
+
+    if not qs.filter(**{fname: value}).exists():
+        return value
+
+    it = generate_value(
+        value,
+        suffix,
+        transform,
+        max_length,
+        max_attempts,
+    )
+
+    new = six.next(it)
+    kwargs = {fname: new}
+
+    while qs.filter(**kwargs).exists():
+        new = six.next(it)
+        kwargs[fname] = new
+
+    return new

sample/migrations/0019_saletag_sale_tag_unique_name.py

@@ -0,0 +1,30 @@
+# Generated by Django 3.2.5 on 2021-07-17 20:26
+
+import django
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("sample", "0018_auto_20210628_2301"),
+    ]
+
+    operations = (
+        [
+            migrations.AddConstraint(
+                model_name="saletag",
+                constraint=models.UniqueConstraint(
+                    fields=("name",), name="sale_tag_unique_name"
+                ),
+            ),
+        ]
+        if django.VERSION >= (2, 2)
+        else [
+            migrations.AlterField(
+                model_name="saletag",
+                name="name",
+                field=models.CharField(max_length=255, unique=True),
+            ),
+        ]
+    )

sample/migrations/0020_auto_20210717_2230.py

@@ -0,0 +1,42 @@
+# Generated by Django 3.2.5 on 2021-07-17 22:30
+import django
+from django.db import migrations, models
+
+import sample.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("sample", "0019_saletag_sale_tag_unique_name"),
+    ]
+
+    operations = (
+        [
+            migrations.AlterField(
+                model_name="tag",
+                name="name",
+                field=models.CharField(
+                    default=sample.models.get_unique_tag_name, max_length=255
+                ),
+            ),
+            migrations.AddConstraint(
+                model_name="tag",
+                constraint=models.UniqueConstraint(
+                    fields=("name",), name="tag_unique_name"
+                ),
+            ),
+        ]
+        if django.VERSION >= (2, 2)
+        else [
+            migrations.AlterField(
+                model_name="tag",
+                name="name",
+                field=models.CharField(
+                    default=sample.models.get_unique_tag_name,
+                    max_length=255,
+                    unique=True,
+                ),
+            ),
+        ]
+    )

sample/models.py

@@ -1,10 +1,16 @@
 from uuid import uuid4
 
+import django
 from django.conf import settings
 from django.db import models
 from django.utils import timezone
 from django.utils.translation import gettext as _
 
+from model_clone.utils import get_unique_default
+
+if django.VERSION >= (2, 2):
+    from django.db.models import UniqueConstraint
+
 from model_clone import CloneMixin
 from model_clone.models import CloneModel
 
@@ -38,15 +44,39 @@ class Meta:
         unique_together = (("first_name", "last_name", "sex"),)
 
 
+def get_unique_tag_name():
+    return get_unique_default(
+        model=Tag,
+        fname="name",
+        value="test-tag",
+    )
+
+
 class Tag(CloneModel):
-    name = models.CharField(max_length=255)
+    name = models.CharField(
+        max_length=255, default=get_unique_tag_name, unique=django.VERSION < (2, 2)
+    )
+
+    if django.VERSION >= (2, 2):
+
+        class Meta:
+            constraints = [
+                UniqueConstraint(fields=["name"], name="tag_unique_name"),
+            ]
 
     def __str__(self):
         return _(self.name)
 
 
 class SaleTag(CloneModel):
-    name = models.CharField(max_length=255)
+    name = models.CharField(max_length=255, unique=django.VERSION < (2, 2))
+
+    if django.VERSION >= (2, 2):
+
+        class Meta:
+            constraints = [
+                UniqueConstraint(fields=["name"], name="sale_tag_unique_name"),
+            ]
 
     def __str__(self):
         return _(self.name)