Add support for UniqueConstraint for uniqueness validation

modelcluster/forms.py

@@ -134,7 +134,9 @@ def validate_unique(self):
         forms_to_delete = self.deleted_forms
         valid_forms = [form for form in self.forms if form.is_valid() and form not in forms_to_delete]
         for form in valid_forms:
-            unique_checks, date_checks = form.instance._get_unique_checks()
+            unique_checks, date_checks = form.instance._get_unique_checks(
+                include_meta_constraints=True
+            )
             all_unique_checks.update(unique_checks)
             all_date_checks.update(date_checks)
 

tests/migrations/0013_add_log_category.py

@@ -0,0 +1,27 @@
+# Generated by Django 4.2.16 on 2024-11-25 12:55
+
+from django.db import migrations, models
+import django.db.models.deletion
+import modelcluster.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tests', '0012_add_record_label'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='LogCategory',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=32)),
+                ('log', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE, related_name='categories', to='tests.log')),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='logcategory',
+            constraint=models.UniqueConstraint(fields=('log', 'name'), name='unique_log_category'),
+        ),
+    ]

tests/models.py

@@ -157,6 +157,22 @@ def __str__(self):
         return "[%s] %s" % (self.time.isoformat(), self.data)
 
 
+class LogCategory(models.Model):
+    log = ParentalKey(Log, related_name="categories", on_delete=models.CASCADE)
+    name = models.CharField(max_length=32)
+
+    def __str__(self):
+        return self.name
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                fields=["log", "name"],
+                name="unique_log_category",
+            )
+        ]
+
+
 class Document(ClusterableModel):
     title = models.CharField(max_length=255)
     file = models.FileField(upload_to='documents')

tests/tests/test_cluster_form.py

@@ -5,7 +5,7 @@
 from django import VERSION as DJANGO_VERSION
 from django.core.exceptions import ValidationError
 from django.test import TestCase
-from tests.models import Band, BandMember, Album, Restaurant, Article, Author, Document, Gallery, Song
+from tests.models import Band, BandMember, Album, Log, Restaurant, Article, Author, Document, Gallery, Song
 from modelcluster.forms import ClusterForm
 from django.forms import Textarea, CharField
 from django.forms.widgets import TextInput, FileInput
@@ -770,6 +770,28 @@ class Meta:
         })
         self.assertFalse(form.is_valid())
 
+    def test_unique_constraint(self):
+        class LogForm(ClusterForm):
+            class Meta:
+                model = Log
+                fields = ["data"]
+                formsets = ["categories"]
+
+        form = LogForm({
+            "data": "User signed in",
+
+            "categories-TOTAL_FORMS": 2,
+            "categories-INITIAL_FORMS": 0,
+            "categories-MAX_NUM_FORMS": 1000,
+
+            "categories-0-name": "user",
+            "categories-0-id": "",
+
+            "categories-1-name": "user",
+            "categories-1-id": "",
+        })
+        self.assertFalse(form.is_valid())
+
 
 class FormWithM2MTest(TestCase):
     def setUp(self):