Merge branch 'cancel-follow-request' into 'develop'

Add support for cancellation of a follow request

Closes #1522

See merge request pleroma/pleroma!2175

lib/pleroma/following_relationship.ex

@@ -58,8 +58,8 @@ defmodule Pleroma.FollowingRelationship do
 
   def unfollow(%User{} = follower, %User{} = following) do
     case get(follower, following) do
-      nil -> {:ok, nil}
       %__MODULE__{} = following_relationship -> Repo.delete(following_relationship)
+      _ -> {:ok, nil}
     end
   end
 

lib/pleroma/user.ex

@@ -647,25 +647,48 @@ defmodule Pleroma.User do
     end
   end
 
+  def unfollow(%User{ap_id: ap_id}, %User{ap_id: ap_id}) do
+    {:error, "Not subscribed!"}
+  end
+
   def unfollow(%User{} = follower, %User{} = followed) do
-    if following?(follower, followed) and follower.ap_id != followed.ap_id do
-      FollowingRelationship.unfollow(follower, followed)
+    case get_follow_state(follower, followed) do
+      state when state in ["accept", "pending"] ->
+        FollowingRelationship.unfollow(follower, followed)
+        {:ok, followed} = update_follower_count(followed)
 
-      {:ok, followed} = update_follower_count(followed)
+        {:ok, follower} =
+          follower
+          |> update_following_count()
+          |> set_cache()
 
-      {:ok, follower} =
-        follower
-        |> update_following_count()
-        |> set_cache()
+        {:ok, follower, Utils.fetch_latest_follow(follower, followed)}
 
-      {:ok, follower, Utils.fetch_latest_follow(follower, followed)}
-    else
-      {:error, "Not subscribed!"}
+      nil ->
+        {:error, "Not subscribed!"}
     end
   end
 
   defdelegate following?(follower, followed), to: FollowingRelationship
 
+  def get_follow_state(%User{} = follower, %User{} = following) do
+    following_relationship = FollowingRelationship.get(follower, following)
+
+    case {following_relationship, following.local} do
+      {nil, false} ->
+        case Utils.fetch_latest_follow(follower, following) do
+          %{data: %{"state" => state}} when state in ["pending", "accept"] -> state
+          _ -> nil
+        end
+
+      {%{state: state}, _} ->
+        state
+
+      {nil, _} ->
+        nil
+    end
+  end
+
   def locked?(%User{} = user) do
     user.locked || false
   end

lib/pleroma/web/activity_pub/utils.ex

@@ -490,6 +490,15 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Repo.one()
   end
 
+  def fetch_latest_undo(%User{ap_id: ap_id}) do
+    "Undo"
+    |> Activity.Queries.by_type()
+    |> where(actor: ^ap_id)
+    |> order_by([activity], fragment("? desc nulls last", activity.id))
+    |> limit(1)
+    |> Repo.one()
+  end
+
   def get_latest_reaction(internal_activity_id, %{ap_id: ap_id}, emoji) do
     %{data: %{"object" => object_ap_id}} = Activity.get_by_id(internal_activity_id)