7 files changed, 47 insertions, 3 deletions
diff --git a/lib/pleroma/constants.ex b/lib/pleroma/constants.ex
index 77bc4bfac..d814b4931 100644
--- a/lib/pleroma/constants.ex
+++ b/lib/pleroma/constants.ex
@@ -76,6 +76,14 @@ defmodule Pleroma.Constants do
     ]
   )
 
+  const(allowed_user_actor_types,
+    do: [
+      "Person",
+      "Service",
+      "Group"
+    ]
+  )
+
   # basic regex, just there to weed out potential mistakes
   # https://datatracker.ietf.org/doc/html/rfc2045#section-5.1
   const(mime_regex,
diff --git a/lib/pleroma/user.ex b/lib/pleroma/user.ex
index 10dafbe6f..0fd1b6365 100644
--- a/lib/pleroma/user.ex
+++ b/lib/pleroma/user.ex
@@ -39,6 +39,7 @@ defmodule Pleroma.User do
   alias Pleroma.Workers.BackgroundWorker
 
   require Logger
+  require Pleroma.Constants
 
   @type t :: %__MODULE__{}
   @type account_status ::
@@ -579,7 +580,7 @@ defmodule Pleroma.User do
     |> validate_format(:nickname, local_nickname_regex())
     |> validate_length(:bio, max: bio_limit)
     |> validate_length(:name, min: 1, max: name_limit)
-    |> validate_inclusion(:actor_type, ["Person", "Service"])
+    |> validate_inclusion(:actor_type, Pleroma.Constants.allowed_user_actor_types())
     |> put_fields()
     |> put_emoji()
     |> put_change_if_present(:bio, &{:ok, parse_bio(&1, struct)})
diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index 32d1a1037..3b0140d96 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -319,6 +319,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
          {:ok, _actor} <- update_last_status_at_if_public(actor, activity),
          _ <- notify_and_stream(activity),
          :ok <- maybe_schedule_poll_notifications(activity),
+         :ok <- maybe_handle_group_posts(activity),
          :ok <- maybe_federate(activity) do
       {:ok, activity}
     else
diff --git a/lib/pleroma/web/activity_pub/side_effects.ex b/lib/pleroma/web/activity_pub/side_effects.ex
index 10f268f05..59b19180d 100644
--- a/lib/pleroma/web/activity_pub/side_effects.ex
+++ b/lib/pleroma/web/activity_pub/side_effects.ex
@@ -233,6 +233,8 @@ defmodule Pleroma.Web.ActivityPub.SideEffects do
 
       Pleroma.Search.add_to_index(Map.put(activity, :object, object))
 
+      Utils.maybe_handle_group_posts(activity)
+
       meta =
         meta
         |> add_notifications(notifications)
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index b32f19740..e2fc2640d 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -935,4 +935,27 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> where([a, object: o], fragment("(?)->>'type' = 'Answer'", o.data))
     |> Repo.all()
   end
+
+  def maybe_handle_group_posts(activity) do
+    poster = User.get_cached_by_ap_id(activity.actor)
+
+    mentions =
+      activity.data["to"]
+      |> Enum.filter(&(&1 != activity.actor))
+
+    mentioned_local_groups =
+      User.get_all_by_ap_id(mentions)
+      |> Enum.filter(fn user ->
+        user.actor_type == "Group" and
+          user.local and
+          not User.blocks?(user, poster)
+      end)
+
+    mentioned_local_groups
+    |> Enum.each(fn group ->
+      Pleroma.Web.CommonAPI.repeat(activity.id, group)
+    end)
+
+    :ok
+  end
 end
diff --git a/lib/pleroma/web/mastodon_api/views/account_view.ex b/lib/pleroma/web/mastodon_api/views/account_view.ex
index 237de3055..e7c555eb2 100644
--- a/lib/pleroma/web/mastodon_api/views/account_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/account_view.ex
@@ -212,7 +212,7 @@ defmodule Pleroma.Web.MastodonAPI.AccountView do
         do: user.follower_count,
         else: 0
 
-    bot = user.actor_type == "Service"
+    bot = is_bot?(user)
 
     emojis =
       Enum.map(user.emoji, fn {shortcode, raw_url} ->
@@ -468,4 +468,12 @@ defmodule Pleroma.Web.MastodonAPI.AccountView do
 
   defp image_url(%{"url" => [%{"href" => href} | _]}), do: href
   defp image_url(_), do: nil
+
+  defp is_bot?(user) do
+    # Because older and/or Mastodon clients may not recognize a Group actor properly,
+    # and currently the group actor can only boost things, we should let these clients
+    # think groups are bots.
+    # See https://git.pleroma.social/pleroma/pleroma-meta/-/issues/14
+    user.actor_type == "Service" || user.actor_type == "Group"
+  end
 end
diff --git a/lib/pleroma/web/mastodon_api/views/instance_view.ex b/lib/pleroma/web/mastodon_api/views/instance_view.ex
index f95b5360a..e514d0e91 100644
--- a/lib/pleroma/web/mastodon_api/views/instance_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/instance_view.ex
@@ -125,7 +125,8 @@ defmodule Pleroma.Web.MastodonAPI.InstanceView do
       if Config.get([:instance, :profile_directory]) do
         "profile_directory"
       end,
-      "pleroma:get:main/ostatus"
+      "pleroma:get:main/ostatus",
+      "pleroma:group_actors"
     ]
     |> Enum.filter(& &1)
   end