UX: Filter only content-translated languages for the language switcher

app/validators/language_switcher_setting_validator.rb

@@ -6,11 +6,12 @@ def initialize(opts = {})
   end
 
   def valid_value?(val)
-    return true if val == "f"
-    SiteSetting.set_locale_from_cookie
+    return true if val == "f" || val == "false"
+    SiteSetting.set_locale_from_cookie &&
+      SiteSetting.automatic_translation_target_languages.present?
   end
 
   def error_message
-    I18n.t("site_settings.errors.set_locale_cookie_requirements")
+    I18n.t("site_settings.errors.experimental_anon_language_switcher_requirements")
   end
 end

assets/javascripts/discourse/components/language-switcher.gjs

@@ -13,14 +13,17 @@ export default class LanguageSwitcher extends Component {
   @service router;
 
   get localeOptions() {
-    return JSON.parse(this.siteSettings.available_locales).map(
-      ({ name, value }) => {
+    const targetLanguages = (
+      this.siteSettings.automatic_translation_target_languages || ""
+    ).split("|");
+    return JSON.parse(this.siteSettings.available_locales)
+      .filter(({ value }) => targetLanguages.includes(value))
+      .map(({ name, value }) => {
         return {
           label: name,
           value,
         };
-      }
-    );
+      });
   }
 
   @action

assets/javascripts/discourse/initializers/extend-for-translate-button.js

@@ -16,7 +16,11 @@ function initializeTranslation(api) {
 
   const currentUser = api.getCurrentUser();
 
-  if (!currentUser && siteSettings.experimental_anon_language_switcher) {
+  if (
+    !currentUser &&
+    siteSettings.experimental_anon_language_switcher &&
+    siteSettings.automatic_translation_target_languages
+  ) {
     api.headerIcons.add(
       "discourse-translator_language-switcher",
       LanguageSwitcher,

config/locales/server.en.yml

@@ -1,6 +1,6 @@
 en:
   site_settings:
-    translator_enabled: "Allow inline translation of posts."
+    translator_enabled: "Enable the translator plugin."
     translator_provider: "The provider of the translation service."
     translator_azure_subscription_key: "Azure Subscription Key"
     translator_azure_region: "Azure Region"
@@ -17,10 +17,10 @@ en:
     translator_azure_custom_subdomain: "Required if using a Virtual Network or Firewall for Azure Cognitive Services. Note: Only enter the custom subdomain not the full custom endpoint."
     restrict_translation_by_group: "Only allowed groups can translate"
     restrict_translation_by_poster_group: "Only allow translation of posts made by users in allowed groups. If empty, allow translations of posts from all users."
-    experimental_anon_language_switcher: "Enable experimental language switcher for anonymous users. This will allow anonymous users to switch between translated versions of Discourse and user-contributed content in topics."
+    experimental_anon_language_switcher: "Enable experimental language switcher. This will allow site visitors who are not logged in to switch between translated versions of Discourse and user-contributed content in topics."
     errors:
-      set_locale_cookie_requirements: "The experimental language switcher for anonymous users requires the `set locale from cookie` site setting to be enabled."
       needs_nonzero_backfill: "Automatic language translation requires the 'automatic_translation_backfill_maximum_translations_per_hour' hidden setting to be a non-zero value. Please approach your site administrator to increase this limit."
+      experimental_anon_language_switcher_requirements: "The experimental language switcher requires the `set locale from cookie` site setting to be enabled, and the `automatic translation target languages` to have at least one language."
     experimental_inline_translation: "Enable experimental inline translation feature. This replaces existing parallel translation, allowing site visitors with a non-default locale to view content in their language."
     automatic_translation_target_languages: "The languages to automatically translate user content (posts, topics) to. If empty, no languages will be automatically translated."
   translator:

config/settings.yml

@@ -16,8 +16,8 @@ discourse_translator:
     validator: "DiscourseTranslator::TranslatorSelectionValidator"
   automatic_translation_target_languages:
     default: ""
-    client: true
     type: list
+    client: true
     list_type: named
     allow_any: false
     choices: "DiscourseTranslator::TranslatableLanguagesSetting.values"

spec/system/anon_language_switcher_spec.rb

@@ -2,6 +2,7 @@
 
 RSpec.describe "Anonymous user language switcher", type: :system do
   fab!(:japanese_user) { Fabricate(:user, locale: "ja") }
+
   it "shows the correct language based on the selected language and login status" do
     SWITCHER_SELECTOR = "button[data-identifier='discourse-translator_language-switcher']"
 
@@ -11,13 +12,23 @@
     SiteSetting.translator_enabled = true
     SiteSetting.allow_user_locale = true
     SiteSetting.set_locale_from_cookie = true
+    SiteSetting.automatic_translation_backfill_maximum_translations_per_hour = 1
+    SiteSetting.automatic_translation_target_languages = "es|ja"
     SiteSetting.experimental_anon_language_switcher = true
     visit("/")
     expect(page).to have_css(SWITCHER_SELECTOR)
     expect(find(".nav-item_latest")).to have_content("Latest")
 
     switcher = PageObjects::Components::DMenu.new(SWITCHER_SELECTOR)
     switcher.expand
+    expect(switcher).to have_content("日本語")
+
+    SiteSetting.automatic_translation_target_languages = "es"
+    SiteSetting.experimental_anon_language_switcher = true
+    visit("/")
+
+    switcher.expand
+    expect(switcher).not_to have_content("日本語")
     switcher.click_button("Español")
     expect(find(".nav-item_latest")).to have_content("Recientes")
 

spec/system/full_page_translation_spec.rb

@@ -33,7 +33,6 @@
       SiteSetting.allow_user_locale = true
       SiteSetting.set_locale_from_cookie = true
       SiteSetting.set_locale_from_param = true
-      SiteSetting.experimental_anon_language_switcher = true
       SiteSetting.experimental_inline_translation = true
     end