snapshot of https://github.com/zulip/zulip.git @ 48c69911c7dd4e03b20552eb3bd77ad8151c1357 (2026-09-15)

zerver/migrations/0803_delete_orphan_recipients_and_huddles.py

@@ -0,0 +1,86 @@
+from django.conf import settings
+from django.db import migrations
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+from django.db.migrations.state import StateApps
+from django.db.models import Exists, OuterRef
+
+STREAM = 2
+DIRECT_MESSAGE_GROUP = 3
+BATCH_SIZE = 1000
+
+
+def delete_orphan_recipients_and_huddles(
+    apps: StateApps, schema_editor: BaseDatabaseSchemaEditor
+) -> None:
+    Recipient = apps.get_model("zerver", "Recipient")
+    Subscription = apps.get_model("zerver", "Subscription")
+    DirectMessageGroup = apps.get_model("zerver", "DirectMessageGroup")
+    UserProfile = apps.get_model("zerver", "UserProfile")
+    Stream = apps.get_model("zerver", "Stream")
+
+    # Stream has no FK from Recipient (only a type_id int); when
+    # realm.delete() cascades the Stream, its Recipient row is left
+    # behind.  Orphans are those whose type_id no longer points at
+    # a live Stream.
+    orphan_stream_recipient_ids = list(
+        Recipient.objects.filter(type=STREAM)
+        .exclude(type_id__in=Stream.objects.values_list("id", flat=True))
+        .values_list("id", flat=True)
+    )
+    print()
+    print(f"Deleting {len(orphan_stream_recipient_ids)} orphan stream recipients...")
+    for chunk_start in range(0, len(orphan_stream_recipient_ids), BATCH_SIZE):
+        chunk = orphan_stream_recipient_ids[chunk_start : chunk_start + BATCH_SIZE]
+        Recipient.objects.filter(id__in=chunk).delete()
+        print(
+            f"  Deleted {chunk_start + len(chunk)}/{len(orphan_stream_recipient_ids)} orphan stream recipients."
+        )
+
+    # A DMG Recipient is orphan when its only remaining Subscriptions
+    # are from cross-realm system bots, or when none remain.
+    crossrealm_bot_ids = set(
+        UserProfile.objects.filter(
+            delivery_email__in=settings.CROSS_REALM_BOT_EMAILS,
+        ).values_list("id", flat=True)
+    )
+    has_human_subscriber = Exists(
+        Subscription.objects.filter(recipient_id=OuterRef("id")).exclude(
+            user_profile_id__in=crossrealm_bot_ids,
+        )
+    )
+    orphan_dmg_recipient_ids = list(
+        Recipient.objects.filter(type=DIRECT_MESSAGE_GROUP)
+        .annotate(has_human=has_human_subscriber)
+        .filter(has_human=False)
+        .values_list("id", flat=True)
+    )
+    print(f"Deleting {len(orphan_dmg_recipient_ids)} orphan direct message groups...")
+    for chunk_start in range(0, len(orphan_dmg_recipient_ids), BATCH_SIZE):
+        chunk = orphan_dmg_recipient_ids[chunk_start : chunk_start + BATCH_SIZE]
+        chunk_huddle_ids = list(
+            Recipient.objects.filter(id__in=chunk).values_list("type_id", flat=True)
+        )
+        # Recipient.delete() cascades Subscription and Message;
+        # DirectMessageGroup.recipient is SET_NULL, so the DMG row
+        # needs an explicit delete.
+        Recipient.objects.filter(id__in=chunk).delete()
+        DirectMessageGroup.objects.filter(id__in=chunk_huddle_ids).delete()
+        print(
+            f"  Deleted {chunk_start + len(chunk)}/{len(orphan_dmg_recipient_ids)} orphan direct message groups."
+        )
+
+
+class Migration(migrations.Migration):
+    atomic = False
+
+    dependencies = [
+        ("zerver", "0802_realmexport_restore_command_line_export_status"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            delete_orphan_recipients_and_huddles,
+            reverse_code=migrations.RunPython.noop,
+            elidable=True,
+        ),
+    ]