scheduled_messages: Store the final delivered message ID.

This could be useful for debugging problems with the system
operationally.

zerver/actions/scheduled_messages.py

@@ -230,10 +230,10 @@ def send_scheduled_message(scheduled_message: ScheduledMessage) -> None:
         scheduled_message.realm,
     )
 
-    # TODO: Store the resulting message ID on the scheduled_message object.
-    do_send_messages([send_request])
+    message_id = do_send_messages([send_request])[0]
+    scheduled_message.delivered_message_id = message_id
     scheduled_message.delivered = True
-    scheduled_message.save(update_fields=["delivered"])
+    scheduled_message.save(update_fields=["delivered", "delivered_message_id"])
     notify_remove_scheduled_message(scheduled_message.sender, scheduled_message.id)
 
 

zerver/migrations/0448_scheduledmessage_new_fields.py

@@ -1,5 +1,6 @@
 # Generated by Django 4.2 on 2023-05-05 00:18
 
+import django.db.models.deletion
 from django.db import migrations, models
 
 
@@ -19,4 +20,11 @@ class Migration(migrations.Migration):
             name="failure_message",
             field=models.TextField(null=True),
         ),
+        migrations.AddField(
+            model_name="scheduledmessage",
+            name="delivered_message",
+            field=models.ForeignKey(
+                null=True, on_delete=django.db.models.deletion.CASCADE, to="zerver.message"
+            ),
+        ),
     ]

zerver/models.py

@@ -4325,6 +4325,7 @@ class ScheduledMessage(models.Model):
     realm = models.ForeignKey(Realm, on_delete=CASCADE)
     scheduled_timestamp = models.DateTimeField(db_index=True)
     delivered = models.BooleanField(default=False)
+    delivered_message = models.ForeignKey(Message, null=True, on_delete=CASCADE)
     has_attachment = models.BooleanField(default=False, db_index=True)
 
     # Metadata for messages that failed to send when their scheduled

zerver/tests/test_retention.py

@@ -1073,7 +1073,7 @@ class TestDoDeleteMessages(ZulipTestCase):
         message_ids = [self.send_stream_message(cordelia, "Verona", str(i)) for i in range(0, 10)]
         messages = Message.objects.filter(id__in=message_ids)
 
-        with self.assert_database_query_count(19):
+        with self.assert_database_query_count(20):
             do_delete_messages(realm, messages)
         self.assertFalse(Message.objects.filter(id__in=message_ids).exists())