Send and handle "Delete" activity for deleted users

lib/pleroma/user.ex

@@ -937,6 +937,8 @@ defmodule Pleroma.User do
 
   @spec perform(atom(), User.t()) :: {:ok, User.t()}
   def perform(:delete, %User{} = user) do
+    {:ok, _user} = ActivityPub.delete(user)
+
     # Remove all relationships
     {:ok, followers} = User.get_followers(user)
 
@@ -953,8 +955,8 @@ defmodule Pleroma.User do
     end)
 
     delete_user_activities(user)
-
-    {:ok, _user} = Repo.delete(user)
+    invalidate_cache(user)
+    Repo.delete(user)
   end
 
   @spec perform(atom(), User.t()) :: {:ok, User.t()}

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -405,6 +405,19 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
+  def delete(%User{ap_id: ap_id, follower_address: follower_address} = user) do
+    with data <- %{
+           "to" => [follower_address],
+           "type" => "Delete",
+           "actor" => ap_id,
+           "object" => %{"type" => "Person", "id" => ap_id}
+         },
+         {:ok, activity} <- insert(data, true, true),
+         :ok <- maybe_federate(activity) do
+      {:ok, user}
+    end
+  end
+
   def delete(%Object{data: %{"id" => id, "actor" => actor}} = object, local \\ true) do
     user = User.get_cached_by_ap_id(actor)
     to = (object.data["to"] || []) ++ (object.data["cc"] || [])

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -641,7 +641,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   # an error or a tombstone.  This would allow us to verify that a deletion actually took
   # place.
   def handle_incoming(
-        %{"type" => "Delete", "object" => object_id, "actor" => _actor, "id" => _id} = data,
+        %{"type" => "Delete", "object" => object_id, "actor" => actor, "id" => _id} = data,
         _options
       ) do
     object_id = Utils.get_ap_id(object_id)
@@ -653,7 +653,30 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
          {:ok, activity} <- ActivityPub.delete(object, false) do
       {:ok, activity}
     else
-      _e -> :error
+      nil ->
+        case User.get_cached_by_ap_id(object_id) do
+          %User{ap_id: ^actor} = user ->
+            {:ok, followers} = User.get_followers(user)
+
+            Enum.each(followers, fn follower ->
+              User.unfollow(follower, user)
+            end)
+
+            {:ok, friends} = User.get_friends(user)
+
+            Enum.each(friends, fn followed ->
+              User.unfollow(user, followed)
+            end)
+
+            User.invalidate_cache(user)
+            Repo.delete(user)
+
+          nil ->
+            :error
+        end
+
+      _e ->
+        :error
     end
   end