Fix emoji reactions for legacy 2-tuple formats

lib/pleroma/object.ex

@@ -425,4 +425,30 @@ defmodule Pleroma.Object do
   end
 
   def object_data_hashtags(_), do: []
+
+  def get_emoji_reactions(object) do
+    reactions = object.data["reactions"]
+
+    if is_list(reactions) or is_map(reactions) do
+      reactions
+      |> Enum.map(fn
+        [_emoji, users, _maybe_url] = item when is_list(users) ->
+          item
+
+        [emoji, users] when is_list(users) ->
+          [emoji, users, nil]
+
+        # This case is here to process the Map situation, which will happen
+        # only with the legacy two-value format.
+        {emoji, users} when is_list(users) ->
+          [emoji, users, nil]
+
+        _ ->
+          nil
+      end)
+      |> Enum.reject(&is_nil/1)
+    else
+      []
+    end
+  end
 end

lib/pleroma/web/activity_pub/utils.ex

@@ -408,11 +408,7 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   end
 
   def get_cached_emoji_reactions(object) do
-    if is_list(object.data["reactions"]) do
-      object.data["reactions"]
-    else
-      []
-    end
+    Object.get_emoji_reactions(object)
   end
 
   @spec add_like_to_object(Activity.t(), Object.t()) ::

lib/pleroma/web/mastodon_api/views/status_view.ex

@@ -334,8 +334,8 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
       end
 
     emoji_reactions =
-      object.data
-      |> Map.get("reactions", [])
+      object
+      |> Object.get_emoji_reactions()
       |> EmojiReactionController.filter_allowed_users(
         opts[:for],
         Map.get(opts, :with_muted, false)

lib/pleroma/web/pleroma_api/controllers/emoji_reaction_controller.ex

@@ -28,8 +28,8 @@ defmodule Pleroma.Web.PleromaAPI.EmojiReactionController do
   def index(%{assigns: %{user: user}} = conn, %{id: activity_id} = params) do
     with true <- Pleroma.Config.get([:instance, :show_reactions]),
          %Activity{} = activity <- Activity.get_by_id_with_object(activity_id),
-         %Object{data: %{"reactions" => reactions}} when is_list(reactions) <-
-           Object.normalize(activity, fetch: false) do
+         %Object{} = object <- Object.normalize(activity, fetch: false),
+         reactions <- Object.get_emoji_reactions(object) do
       reactions =
         reactions
         |> filter(params)
@@ -60,9 +60,6 @@ defmodule Pleroma.Web.PleromaAPI.EmojiReactionController do
     reactions
     |> Stream.map(fn
       [emoji, users, url] when is_list(users) -> filter_emoji.(emoji, users, url)
-      {emoji, users, url} when is_list(users) -> filter_emoji.(emoji, users, url)
-      {emoji, users} when is_list(users) -> filter_emoji.(emoji, users, nil)
-      _ -> nil
     end)
     |> Stream.reject(&is_nil/1)
   end