Clean up bookmarks after prune_objects

When doing prune_objects, it's possible that bookmarked objects are deleted.
This gave problems when fetching the bookmark TL.
Here we clean up the bookmarks during pruning in the case were it's possible that bookmarked objects are deleted.

lib/mix/tasks/pleroma/database.ex

@@ -171,6 +171,21 @@ def run(["prune_objects" | args]) do
     end
     |> Repo.delete_all(timeout: :infinity)
 
+    if !Keyword.get(options, :keep_threads) do
+      # Without the --keep-threads option, it's possible that bookmarked
+      # objects have been deleted. We remove the corresponding bookmarks.
+      """
+      delete from public.bookmarks
+      where id in (
+        select b.id from public.bookmarks b
+        left join public.activities a on b.activity_id = a.id
+        left join public.objects o on a."data" ->> 'object' = o.data ->> 'id'
+        where o.id is null
+      )
+      """
+      |> Repo.query([], timeout: :infinity)
+    end
+
     if Keyword.get(options, :prune_orphaned_activities) do
       # Prune activities who link to a single object
       """

test/mix/tasks/pleroma/database_test.exs

@@ -7,6 +7,7 @@ defmodule Mix.Tasks.Pleroma.DatabaseTest do
   use Oban.Testing, repo: Pleroma.Repo
 
   alias Pleroma.Activity
+  alias Pleroma.Bookmark
   alias Pleroma.Object
   alias Pleroma.Repo
   alias Pleroma.User
@@ -87,6 +88,29 @@ test "it prunes old objects from the database", %{old_insert_date: old_insert_da
       refute Object.get_by_id(note_remote_non_public_id)
     end
 
+    test "it cleans up bookmarks", %{old_insert_date: old_insert_date} do
+      user = insert(:user)
+      {:ok, old_object_activity} = CommonAPI.post(user, %{status: "yadayada"})
+
+      Repo.one(Object)
+      |> Ecto.Changeset.change(%{updated_at: old_insert_date})
+      |> Repo.update!()
+
+      {:ok, new_object_activity} = CommonAPI.post(user, %{status: "yadayada"})
+
+      {:ok, _} = Bookmark.create(user.id, old_object_activity.id)
+      {:ok, _} = Bookmark.create(user.id, new_object_activity.id)
+
+      assert length(Repo.all(Object)) == 2
+      assert length(Repo.all(Bookmark)) == 2
+
+      Mix.Tasks.Pleroma.Database.run(["prune_objects"])
+
+      assert length(Repo.all(Object)) == 1
+      assert length(Repo.all(Bookmark)) == 1
+      refute Bookmark.get(user.id, old_object_activity.id)
+    end
+
     test "with the --keep-non-public option it still keeps non-public posts even if they are not local",
          %{old_insert_date: old_insert_date} do
       insert(:note)