From 35e9282ffdafd8a04d1c09ec5eff3f176bb389de Mon Sep 17 00:00:00 2001
From: lain <lain@soykaf.club>
Date: Mon, 22 Jun 2020 10:35:11 +0200
Subject: [PATCH] HellthreadPolicy: Restrict to Notes and Articles.

---
 .../web/activity_pub/mrf/hellthread_policy.ex  |  7 +++++--
 .../mrf/hellthread_policy_test.exs             | 18 +++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/mrf/hellthread_policy.ex b/lib/pleroma/web/activity_pub/mrf/hellthread_policy.ex
index 1764bc789..f6b2c4415 100644
--- a/lib/pleroma/web/activity_pub/mrf/hellthread_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/hellthread_policy.ex
@@ -13,8 +13,10 @@ defmodule Pleroma.Web.ActivityPub.MRF.HellthreadPolicy do
 
   defp delist_message(message, threshold) when threshold > 0 do
     follower_collection = User.get_cached_by_ap_id(message["actor"]).follower_address
+    to = message["to"] || []
+    cc = message["cc"] || []
 
-    follower_collection? = Enum.member?(message["to"] ++ message["cc"], follower_collection)
+    follower_collection? = Enum.member?(to ++ cc, follower_collection)
 
     message =
       case get_recipient_count(message) do
@@ -71,7 +73,8 @@ defmodule Pleroma.Web.ActivityPub.MRF.HellthreadPolicy do
   end
 
   @impl true
-  def filter(%{"type" => "Create"} = message) do
+  def filter(%{"type" => "Create", "object" => %{"type" => object_type}} = message)
+      when object_type in ~w{Note Article} do
     reject_threshold =
       Pleroma.Config.get(
         [:mrf_hellthread, :reject_threshold],
diff --git a/test/web/activity_pub/mrf/hellthread_policy_test.exs b/test/web/activity_pub/mrf/hellthread_policy_test.exs
index 95ef0b168..6e9daa7f9 100644
--- a/test/web/activity_pub/mrf/hellthread_policy_test.exs
+++ b/test/web/activity_pub/mrf/hellthread_policy_test.exs
@@ -8,6 +8,8 @@ defmodule Pleroma.Web.ActivityPub.MRF.HellthreadPolicyTest do
 
   import Pleroma.Web.ActivityPub.MRF.HellthreadPolicy
 
+  alias Pleroma.Web.CommonAPI
+
   setup do
     user = insert(:user)
 
@@ -20,7 +22,10 @@ defmodule Pleroma.Web.ActivityPub.MRF.HellthreadPolicyTest do
         "https://instance.tld/users/user1",
         "https://instance.tld/users/user2",
         "https://instance.tld/users/user3"
-      ]
+      ],
+      "object" => %{
+        "type" => "Note"
+      }
     }
 
     [user: user, message: message]
@@ -28,6 +33,17 @@ defmodule Pleroma.Web.ActivityPub.MRF.HellthreadPolicyTest do
 
   setup do: clear_config(:mrf_hellthread)
 
+  test "doesn't die on chat messages" do
+    Pleroma.Config.put([:mrf_hellthread], %{delist_threshold: 2, reject_threshold: 0})
+
+    user = insert(:user)
+    other_user = insert(:user)
+
+    {:ok, activity} = CommonAPI.post_chat_message(user, other_user, "moin")
+
+    assert {:ok, _} = filter(activity.data)
+  end
+
   describe "reject" do
     test "rejects the message if the recipient count is above reject_threshold", %{
       message: message