From 4f44fd32eae100d5ce74b3c9bd5457858f145198 Mon Sep 17 00:00:00 2001
From: Tusooa Zhu <tusooa@kazv.moe>
Date: Sun, 12 Sep 2021 21:52:44 -0400
Subject: [PATCH] Federate unfollow activity in move_following properly

0: Use the CommonAPI unfollow function to make sure the
unfollow activity is federated.

1: Limit the follow and unfollow to local followers only,
while let the romote servers decide whether to move their followers.

Ref: emit-move
---
 lib/pleroma/following_relationship.ex         |  3 +-
 .../web/activity_pub/activity_pub_test.exs    | 36 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/lib/pleroma/following_relationship.ex b/lib/pleroma/following_relationship.ex
index a0c7e6e39..61d36ce93 100644
--- a/lib/pleroma/following_relationship.ex
+++ b/lib/pleroma/following_relationship.ex
@@ -194,11 +194,12 @@ def move_following(origin, target) do
     |> join(:inner, [r], f in assoc(r, :follower))
     |> where(following_id: ^origin.id)
     |> where([r, f], f.allow_following_move == true)
+    |> where([r, f], f.local == true)
     |> limit(50)
     |> preload([:follower])
     |> Repo.all()
     |> Enum.map(fn following_relationship ->
-      Repo.delete(following_relationship)
+      Pleroma.Web.CommonAPI.unfollow(following_relationship.follower, origin)
       Pleroma.Web.CommonAPI.follow(following_relationship.follower, target)
     end)
     |> case do
diff --git a/test/pleroma/web/activity_pub/activity_pub_test.exs b/test/pleroma/web/activity_pub/activity_pub_test.exs
index 3021f2995..dec28f81b 100644
--- a/test/pleroma/web/activity_pub/activity_pub_test.exs
+++ b/test/pleroma/web/activity_pub/activity_pub_test.exs
@@ -1775,6 +1775,42 @@ test "old user must be in the new user's `also_known_as` list" do
       assert {:error, "Target account must have the origin in `alsoKnownAs`"} =
                ActivityPub.move(old_user, new_user)
     end
+
+    test "do not move remote user following relationships" do
+      %{ap_id: old_ap_id} = old_user = insert(:user)
+      %{ap_id: new_ap_id} = new_user = insert(:user, also_known_as: [old_ap_id])
+      follower_remote = insert(:user, local: false)
+
+      User.follow(follower_remote, old_user)
+
+      assert User.following?(follower_remote, old_user)
+
+      assert {:ok, activity} = ActivityPub.move(old_user, new_user)
+
+      assert %Activity{
+               actor: ^old_ap_id,
+               data: %{
+                 "actor" => ^old_ap_id,
+                 "object" => ^old_ap_id,
+                 "target" => ^new_ap_id,
+                 "type" => "Move"
+               },
+               local: true
+             } = activity
+
+      params = %{
+        "op" => "move_following",
+        "origin_id" => old_user.id,
+        "target_id" => new_user.id
+      }
+
+      assert_enqueued(worker: Pleroma.Workers.BackgroundWorker, args: params)
+
+      Pleroma.Workers.BackgroundWorker.perform(%Oban.Job{args: params})
+
+      assert User.following?(follower_remote, old_user)
+      refute User.following?(follower_remote, new_user)
+    end
   end
 
   test "doesn't retrieve replies activities with exclude_replies" do