Merge pull request 'mrf/object_age: fix handling of non-public objects' (#851) from Oneric/akkoma:mrf-fix-oage into develop

Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/851

CHANGELOG.md

@@ -28,6 +28,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - AP objects with additional JSON-LD profiles beyond ActivityStreams can now be fetched
 - Single-selection polls no longer expose the voter_count; MastoAPI demands it be null
   and this confused some clients leading to vote distributions >100%
+- ObjectAge policy no longer lets unlisted posts slip through
+- ObjectAge policy no longer leaks belated DMs and follower-only posts
 
 ## Changed
 - Refactored Rich Media to cache the content in the database. Fetching operations that could block status rendering have been eliminated.

lib/pleroma/web/activity_pub/mrf/object_age_policy.ex

@@ -34,16 +34,34 @@ defp check_reject(message, actions) do
     end
   end
 
+  @spec delete_and_count(list(), term()) :: {integer(), list()}
+  defp delete_and_count(list, element), do: delete_and_count(list, element, {0, [], list})
+
+  defp delete_and_count([], _element, {0, _nlist, olist}), do: {0, olist}
+  defp delete_and_count([], _element, {count, nlist, _olist}), do: {count, Enum.reverse(nlist)}
+
+  defp delete_and_count([h | r], h, {count, nlist, olist}),
+    do: delete_and_count(r, h, {count + 1, nlist, olist})
+
+  defp delete_and_count([h | r], element, {count, nlist, olist}),
+    do: delete_and_count(r, element, {count, [h | nlist], olist})
+
+  defp insert_if_needed(list, oldcount, element) do
+    if oldcount <= 0 || Enum.member?(list, element) do
+      list
+    else
+      [element | list]
+    end
+  end
+
   defp check_delist(message, actions) do
     if :delist in actions do
       with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
-        to =
-          List.delete(message["to"] || [], Pleroma.Constants.as_public()) ++
-            [user.follower_address]
+        {pubcnt, to} = delete_and_count(message["to"] || [], Pleroma.Constants.as_public())
+        {flwcnt, cc} = delete_and_count(message["cc"] || [], user.follower_address)
 
-        cc =
-          List.delete(message["cc"] || [], user.follower_address) ++
-            [Pleroma.Constants.as_public()]
+        cc = insert_if_needed(cc, pubcnt, Pleroma.Constants.as_public())
+        to = insert_if_needed(to, flwcnt, user.follower_address)
 
         message =
           message
@@ -65,8 +83,8 @@ defp check_delist(message, actions) do
   defp check_strip_followers(message, actions) do
     if :strip_followers in actions do
       with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
-        to = List.delete(message["to"] || [], user.follower_address)
-        cc = List.delete(message["cc"] || [], user.follower_address)
+        {_, to} = delete_and_count(message["to"] || [], user.follower_address)
+        {_, cc} = delete_and_count(message["cc"] || [], user.follower_address)
 
         message =
           message

test/pleroma/web/activity_pub/mrf/object_age_policy_test.exs

@@ -79,7 +79,7 @@ test "works with objects with empty to or cc fields" do
 
       {:ok, data} = ObjectAgePolicy.filter(data)
 
-      assert Visibility.get_visibility(%{data: data}) == "unlisted"
+      assert Visibility.get_visibility(%{data: data}) == "direct"
     end
 
     test "it delists an old post" do