Do not call LanguageDetector when not language is provided

Signed-off-by: mkljczk <git@mkljczk.pl>

lib/pleroma/web/activity_pub/object_validators/common_fixes.ex

@@ -152,11 +152,19 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
   def maybe_add_language(object) do
     language =
       [
-        get_language_from_context(object),
-        get_language_from_content_map(object),
-        get_language_from_content(object)
+        &get_language_from_context/1,
+        &get_language_from_content_map/1,
+        &get_language_from_content/1
       ]
-      |> Enum.find(&good_locale_code?(&1))
+      |> Enum.find_value(fn get_language ->
+        language = get_language.(object)
+
+        if good_locale_code?(language) do
+          language
+        else
+          nil
+        end
+      end)
 
     if language do
       Map.put(object, "language", language)
@@ -189,8 +197,8 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
 
   defp get_language_from_content_map(_), do: nil
 
-  defp get_language_from_content(%{"summary" => summary, "content" => content}) do
-    LanguageDetector.detect("#{summary} #{content}")
+  defp get_language_from_content(%{"content" => content} = object) do
+    LanguageDetector.detect("#{object["summary"] || ""} #{content}")
   end
 
   defp get_language_from_content(_), do: nil

test/pleroma/web/activity_pub/object_validators/article_note_page_validator_test.exs

@@ -9,6 +9,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidatorTest
   alias Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidator
   alias Pleroma.Web.ActivityPub.Utils
 
+  import Mock
   import Pleroma.Factory
 
   describe "Notes" do
@@ -234,6 +235,28 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidatorTest
       assert object.language == "pl"
     end
 
+    test_with_mock "it doesn't call LanguageDetector when language is specified",
+                   Pleroma.Language.LanguageDetector,
+                   detect: fn _ -> nil end do
+      user = insert(:user)
+
+      note = %{
+        "to" => ["https://www.w3.org/ns/activitystreams#Public"],
+        "cc" => [],
+        "id" => Utils.generate_object_id(),
+        "type" => "Note",
+        "content" => "a post in English",
+        "contentMap" => %{
+          "en" => "a post in English"
+        },
+        "attributedTo" => user.ap_id
+      }
+
+      ArticleNotePageValidator.cast_and_apply(note)
+
+      refute called(Pleroma.Language.LanguageDetector.detect(:_))
+    end
+
     test "it adds contentMap if language is specified" do
       user = insert(:user)