Add support for incoming remote unfollows

lib/pleroma/user.ex

@@ -404,18 +404,22 @@ defmodule Pleroma.User do
       from(
         u in User,
         select_merge: %{
-          search_distance: fragment(
-            "? <-> (? || ?)",
-            ^query,
-            u.nickname,
-            u.name
-          )}
+          search_distance:
+            fragment(
+              "? <-> (? || ?)",
+              ^query,
+              u.nickname,
+              u.name
+            )
+        }
       )
 
-    q = from(s in subquery(inner),
-      order_by: s.search_distance,
-      limit: 20
-    )
+    q =
+      from(
+        s in subquery(inner),
+        order_by: s.search_distance,
+        limit: 20
+      )
 
     Repo.all(q)
   end

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -241,6 +241,24 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
+  def handle_incoming(
+        %{
+          "type" => "Undo",
+          "object" => %{"type" => "Follow", "object" => followed},
+          "actor" => follower,
+          "id" => id
+        } = data
+      ) do
+    with %User{local: true} = followed = User.get_cached_by_ap_id(followed),
+         %User{} = follower = User.get_or_fetch_by_ap_id(follower),
+         {:ok, activity} <- ActivityPub.unfollow(follower, followed, false) do
+      User.unfollow(follower, followed)
+      {:ok, activity}
+    else
+      e -> :error
+    end
+  end
+
   # TODO
   # Accept
   # Undo for non-Announce