Pubsub notifications not being sent on a cascade_destroy

[sevenseacat]

I've tried to replicate this in a failing test in Ash and I can't, which is frustrating. I have it as a failing test in my app though, so I'll try to break that down here.

Describe the bug

When adding cascade_destroy to a resource, and the cascaded records have pubsub notifications configured on destroy, the pubsub notifications are not being generated/sent.

This failure only started occurring after this commit - 23d7479

To Reproduce

Short version - see failing test in Tunez mix test test/tunez/music/album_test.exs:70

Long version:

• An Album resource:

defmodule Tunez.Music.Album do
  use Ash.Resource,
    domain: Tunez.Music,
    data_layer: AshPostgres.DataLayer

  actions do 
    destroy :destroy do
      change cascade_destroy(:notifications, return_notifications?: true)
    end
  end

  relationships do 
    has_many :notifications, Tunez.Accounts.Notification
  end
end

• A Notification resource

defmodule Tunez.Accounts.Notification do
  use Ash.Resource,
    domain: Tunez.Accounts,
    data_layer: AshPostgres.DataLayer,
    notifiers: [Ash.Notifier.PubSub]

  postgres do
    references do
      reference :album, deferrable: :initially
    end
  end

  pub_sub do
    prefix "notifications"
    module TunezWeb.Endpoint
    publish :destroy, [:user_id, "destroy"]
  end

  relationships do
    belongs_to :user, Tunez.Accounts.User do
      allow_nil? false
    end

    belongs_to :album, Tunez.Music.Album do
      domain Tunez.Music
    end
  end

  actions do
    defaults [:read, :destroy]
  end
end

• The test:

    test "sends pubsub notifications about the notification deletion" do
      follower = insert(:user)
      album = insert(:album)
      %{id: notification_id} = insert(:notification, %{album: album, user: follower})
      TunezWeb.Endpoint.subscribe("notifications:#{follower.id}:destroy")

      Music.destroy_album!(album, authorize?: false)

      assert_received %Phoenix.Socket.Broadcast{
        payload: %{data: %{id: ^notification_id}, action: %{name: :destroy}}
      }
    end
  end

  1) test destroy sends pubsub notifications about the notification deletion (TunezWeb.Music.AlbumTest)
     test/tunez/music/album_test.exs:62
     Assertion failed, no matching message after 0ms
     The following variables were pinned:
       notification_id = "9085a13b-3042-4445-a513-4a8164dcfa65"
     The process mailbox is empty.
     code: assert_received %Phoenix.Socket.Broadcast{payload: %{data: %{id: ^notification_id}, action: %{name: :destroy}}}
     stacktrace:
       test/tunez/music/album_test.exs:70: (test)

On an interesting note, if I change the test to use Music.destroy_album!(album, authorize?: false, return_notifications?: true) I do get the notification returned, so its being generated, just not sent? This isn't a bulk action - it's only a single record. I'm not sure what's going on and can't really replicate it anywhere else.

Expected behavior

The test should pass, as it is subscribed to a topic that a pubsub broadcast should be being sent on, when the cascaded record is destroyed.

Runtime

• Elixir version 1.16.2-otp-26
• Erlang version 26.2.3
• OS macOS something
• Ash version main branch, sha 9fc5ddf
• any related extension versions AshPostgres 2.0.1 (not sure if related?)