Allow nested collections

core/migrations/0019_remove_collectionsection_unique_collection_item_and_more.py

@@ -0,0 +1,40 @@
+# Generated by Django 5.2.17 on 2026-08-30 11:23
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0018_remove_collection_tags_collection_filter_tags_and_more'),
+    ]
+
+    operations = [
+        migrations.RemoveConstraint(
+            model_name='collectionsection',
+            name='unique_collection_item',
+        ),
+        migrations.AddField(
+            model_name='collectionsection',
+            name='sub_collection',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='containing_sections', to='core.collection'),
+        ),
+        migrations.AlterField(
+            model_name='collectionsection',
+            name='item',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='collection_sections', to='core.item'),
+        ),
+        migrations.AddConstraint(
+            model_name='collectionsection',
+            constraint=models.CheckConstraint(condition=models.Q(models.Q(('item__isnull', False), ('sub_collection__isnull', True)), models.Q(('item__isnull', True), ('sub_collection__isnull', False)), _connector='OR'), name='collection_section_exactly_one_target'),
+        ),
+        migrations.AddConstraint(
+            model_name='collectionsection',
+            constraint=models.UniqueConstraint(condition=models.Q(('item__isnull', False)), fields=('collection', 'item'), name='unique_collection_item'),
+        ),
+        migrations.AddConstraint(
+            model_name='collectionsection',
+            constraint=models.UniqueConstraint(condition=models.Q(('sub_collection__isnull', False)), fields=('collection', 'sub_collection'), name='unique_collection_sub_collection'),
+        ),
+    ]