feat: backfill latest advisory for existing v2 advisories

Signed-off-by: Keshav Priyadarshi <git@keshav.space>

Author: keshav-space

vulnerabilities/migrations/0121_advisoryv2_is_latest_alter_advisoryv2_advisory_id_and_more.py

@@ -0,0 +1,65 @@
+# Generated by Django 5.2.11 on 2026-04-13 19:05
+
+from django.db import migrations
+from django.db import models
+from django.db.models import F
+
+
+class Migration(migrations.Migration):
+    def add_is_latest_on_existing_advisory(apps, schema_editor):
+        Advisory = apps.get_model("vulnerabilities", "AdvisoryV2")
+
+        print(f"\nUpdating is_latest on existing V2 Advisory.")
+        latest_qs = Advisory.objects.order_by(
+            "avid",
+            F("date_collected").desc(nulls_last=True),
+            "-id",
+        ).distinct("avid")
+
+        Advisory.objects.filter(id__in=latest_qs.values("id")).update(is_latest=True)
+
+    dependencies = [
+        ("vulnerabilities", "0120_impactedpackage_last_range_unfurl_at_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="advisoryv2",
+            name="is_latest",
+            field=models.BooleanField(
+                db_index=True,
+                default=False,
+                help_text="Indicates whether this is the latest version of the advisory identified by its AVID.",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="advisoryv2",
+            name="advisory_id",
+            field=models.CharField(
+                db_index=True,
+                help_text="An advisory is a unique vulnerability identifier in some database, such as PYSEC-2020-2233",
+                max_length=500,
+            ),
+        ),
+        migrations.AlterField(
+            model_name="advisoryv2",
+            name="datasource_id",
+            field=models.CharField(
+                db_index=True,
+                help_text="Unique ID for the datasource used for this advisory .e.g.: nginx_importer_v2",
+                max_length=200,
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name="advisoryv2",
+            constraint=models.UniqueConstraint(
+                condition=models.Q(("is_latest", True)),
+                fields=("avid",),
+                name="unique_latest_per_avid",
+            ),
+        ),
+        migrations.RunPython(
+            code=add_is_latest_on_existing_advisory,
+            reverse_code=migrations.RunPython.noop,
+        ),
+    ]