Fix multiple-choice poll detection

lib/pleroma/object.ex

@@ -255,6 +255,12 @@ def increase_replies_count(ap_id) do
     end
   end
 
+  defp poll_is_multiple?(%Object{data: %{"anyOf" => anyOf}}) do
+    !Enum.empty?(anyOf)
+  end
+
+  defp poll_is_multiple?(_), do: false
+
   def decrease_replies_count(ap_id) do
     Object
     |> where([o], fragment("?->>'id' = ?::text", o.data, ^to_string(ap_id)))
@@ -281,10 +287,10 @@ def decrease_replies_count(ap_id) do
   def increase_vote_count(ap_id, name, actor) do
     with %Object{} = object <- Object.normalize(ap_id),
          "Question" <- object.data["type"] do
-      multiple = Map.has_key?(object.data, "anyOf")
+      key = if poll_is_multiple?(object), do: "anyOf", else: "oneOf"
 
       options =
-        (object.data["anyOf"] || object.data["oneOf"] || [])
+        object.data[key]
         |> Enum.map(fn
           %{"name" => ^name} = option ->
             Kernel.update_in(option["replies"]["totalItems"], &(&1 + 1))
@@ -296,11 +302,8 @@ def increase_vote_count(ap_id, name, actor) do
       voters = [actor | object.data["voters"] || []] |> Enum.uniq()
 
       data =
-        if multiple do
-          Map.put(object.data, "anyOf", options)
-        else
-          Map.put(object.data, "oneOf", options)
-        end
+        object.data
+        |> Map.put(key, options)
         |> Map.put("voters", voters)
 
       object

lib/pleroma/web/common_api/common_api.ex

@@ -340,8 +340,13 @@ defp validate_existing_votes(%{ap_id: ap_id}, object) do
     end
   end
 
-  defp get_options_and_max_count(%{data: %{"anyOf" => any_of}}), do: {any_of, Enum.count(any_of)}
-  defp get_options_and_max_count(%{data: %{"oneOf" => one_of}}), do: {one_of, 1}
+  defp get_options_and_max_count(%{data: %{"anyOf" => any_of}})
+       when is_list(any_of) and any_of != [],
+       do: {any_of, Enum.count(any_of)}
+
+  defp get_options_and_max_count(%{data: %{"oneOf" => one_of}})
+       when is_list(one_of) and one_of != [],
+       do: {one_of, 1}
 
   defp normalize_and_validate_choices(choices, object) do
     choices = Enum.map(choices, fn i -> if is_binary(i), do: String.to_integer(i), else: i end)

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

@@ -28,10 +28,10 @@ def render("show.json", %{object: object, multiple: multiple, options: options}
 
   def render("show.json", %{object: object} = params) do
     case object.data do
-      %{"anyOf" => options} when is_list(options) ->
+      %{"anyOf" => options} when is_list(options) and options != [] ->
         render(__MODULE__, "show.json", Map.merge(params, %{multiple: true, options: options}))
 
-      %{"oneOf" => options} when is_list(options) ->
+      %{"oneOf" => options} when is_list(options) and options != [] ->
         render(__MODULE__, "show.json", Map.merge(params, %{multiple: false, options: options}))
 
       _ ->