fix(streaming): preserve followed domain exception

changelog.d/stream-domain-block-following.fix

@@ -0,0 +1 @@
+Keep followed users visible in streams when their domain is blocked.

lib/pleroma/web/streamer.ex

@@ -195,6 +195,9 @@ defmodule Pleroma.Web.Streamer do
     recipients = MapSet.new(item.recipients)
     domain_blocks = Pleroma.Web.ActivityPub.MRF.subdomains_regex(user.domain_blocks)
 
+    following_ap_ids =
+      if user.domain_blocks == [], do: [], else: User.get_cached_user_friends_ap_ids(user)
+
     with parent <- Object.normalize(item, fetch: false) || item,
          true <- Enum.all?([blocked_ap_ids, muted_ap_ids], &(item.actor not in &1)),
          true <- item.data["type"] != "Announce" || item.actor not in reblog_muted_ap_ids,
@@ -205,8 +208,12 @@ defmodule Pleroma.Web.Streamer do
          true <- MapSet.disjoint?(recipients, recipient_blocks),
          %{host: item_host} <- URI.parse(item.actor),
          %{host: parent_host} <- URI.parse(parent.data["actor"]),
-         false <- Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, item_host),
-         false <- Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, parent_host),
+         false <-
+           item.actor not in following_ap_ids and
+             Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, item_host),
+         false <-
+           parent.data["actor"] not in following_ap_ids and
+             Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, parent_host),
          true <- thread_containment(item, user),
          false <- CommonAPI.thread_muted?(parent, user) do
       false

test/pleroma/web/streamer_test.exs

@@ -475,6 +475,20 @@ defmodule Pleroma.Web.StreamerTest do
       assert Streamer.filtered_by_user?(user, favorite_activity)
     end
 
+    test "it does not filter followed users on blocked domains", %{user: user} do
+      followed =
+        insert(:user, %{ap_id: "https://hecking-lewd-place.com/user/friend"})
+
+      {:ok, user} = User.block_domain(user, "hecking-lewd-place.com")
+      {:ok, activity} = CommonAPI.post(followed, %{status: "still a friend"})
+
+      assert Streamer.filtered_by_user?(user, activity)
+
+      {:ok, user, _followed} = User.follow(user, followed)
+
+      refute Streamer.filtered_by_user?(user, activity)
+    end
+
     test "it sends follow activities to the 'user:notification' stream", %{
       user: user,
       token: oauth_token