add migration file

Signed-off-by: tdruez <tdruez@aboutcode.org>

Author: tdruez

scanpipe/migrations/0082_project_labels_json.py

@@ -0,0 +1,76 @@
+# Generated by Django 6.0.5 on 2026-07-02 13:07
+
+from django.db import migrations, models
+
+
+def populate_labels_json(apps, schema_editor):
+    """
+    Copy the existing django-taggit labels into the new ``labels_json`` field.
+    Raw SQL is used against the legacy ``scanpipe_uuidtaggeditem`` and
+    ``taggit_tag`` tables since the "taggit" app is no longer installed and has no
+    ORM model available in this migration state.
+    """
+    Project = apps.get_model("scanpipe", "Project")
+
+    with schema_editor.connection.cursor() as cursor:
+        existing_tables = schema_editor.connection.introspection.table_names(cursor)
+        if "scanpipe_uuidtaggeditem" not in existing_tables:
+            return
+
+        cursor.execute(
+            "SELECT tagged_item.object_id, tag.name "
+            "FROM scanpipe_uuidtaggeditem AS tagged_item "
+            "JOIN taggit_tag AS tag ON tag.id = tagged_item.tag_id "
+            "ORDER BY tag.name"
+        )
+        rows = cursor.fetchall()
+
+    if not rows:
+        return
+
+    labels_by_project_id = {}
+    for project_id, label in rows:
+        labels_by_project_id.setdefault(project_id, []).append(label)
+
+    projects = [
+        Project(pk=project_id, labels_json=labels)
+        for project_id, labels in labels_by_project_id.items()
+    ]
+    Project.objects.bulk_update(projects, ["labels_json"], batch_size=1000)
+
+
+def drop_legacy_taggit_tables(apps, schema_editor):
+    """Drop the legacy django-taggit tables now that their data has been migrated."""
+    with schema_editor.connection.cursor() as cursor:
+        cursor.execute("DROP TABLE IF EXISTS scanpipe_uuidtaggeditem")
+        # The default django-taggit through table, unused since Project.labels used
+        # the custom UUIDTaggedItem through table, but still created by taggit's own
+        # migrations.
+        cursor.execute("DROP TABLE IF EXISTS taggit_taggeditem")
+        cursor.execute("DROP TABLE IF EXISTS taggit_tag")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('scanpipe', '0081_project_count_fields'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='project',
+            name='labels_json',
+            field=models.JSONField(
+                blank=True, 
+                default=list, 
+                help_text='A list of labels for this project.',
+            ),
+        ),
+        migrations.RunPython(populate_labels_json, migrations.RunPython.noop),
+        migrations.RunPython(drop_legacy_taggit_tables, migrations.RunPython.noop),
+        migrations.RenameField(
+            model_name='project',
+            old_name='labels_json',
+            new_name='labels',
+        ),
+    ]