Fix loading language from system UI languages

Fixes #1847

src/core/translations.cpp

@@ -41,17 +41,19 @@ Translations::~Translations() {
 
 }
 
-void Translations::LoadTranslation(const QString &prefix, const QString &path, const QString &language) {
+bool Translations::LoadTranslation(const QString &prefix, const QString &path, const QString &language) {
 
   const QString basefilename = prefix + u'_' + language;
   QTranslator *t = new QTranslator;
-  if (t->load(basefilename, path)) {
+  if (!t->load(basefilename, path)) {
-    qLog(Debug) << "Tranlations loaded from" << basefilename;
-    QCoreApplication::installTranslator(t);
-    translations_ << t;
-  }
-  else {
     delete t;
+    return false;
   }
 
+  qLog(Debug) << "Tranlations loaded from" << basefilename;
+  QCoreApplication::installTranslator(t);
+  translations_ << t;
+
+  return true;
+
 }

src/core/translations.h

@@ -31,7 +31,7 @@ class Translations {
  public:
   explicit Translations();
   ~Translations();
-  void LoadTranslation(const QString &prefix, const QString &path, const QString &language);
+  bool LoadTranslation(const QString &prefix, const QString &path, const QString &language);
 
  private:
   QList<QTranslator*> translations_;

src/main.cpp

@@ -260,46 +260,76 @@ int main(int argc, char *argv[]) {
   IconLoader::Init();
 
 #ifdef HAVE_TRANSLATIONS
-  QString language = options.language();
+
-  if (language.isEmpty()) {
+  QStringList languages;
-    Settings s;
+
-    s.beginGroup(BehaviourSettings::kSettingsGroup);
+  // Load language from command line options
-    language = s.value(BehaviourSettings::kLanguage).toString();
+  if (!options.language().isEmpty()) {
-    s.endGroup();
+    languages << options.language();
   }
 
-  if (language.isEmpty()) {
+  // Load language from settings
+  if (languages.isEmpty()) {
+    Settings s;
+    s.beginGroup(BehaviourSettings::kSettingsGroup);
+    const QString language = s.value(BehaviourSettings::kLanguage).toString();
+    s.endGroup();
+    if (!language.isEmpty()) {
+      languages << language;
+    }
+  }
+
+  // Use system UI languages
+  if (languages.isEmpty()) {
 #if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
-    const QStringList system_languages = QLocale::system().uiLanguages(QLocale::TagSeparator::Underscore);
+     languages = QLocale::system().uiLanguages(QLocale::TagSeparator::Underscore);
 #else
     const QStringList system_languages = QLocale::system().uiLanguages();
-#endif
+    for (const QString &language : system_languages) {
-    if (system_languages.isEmpty()) {
+      QString language_underscore = language;
-      language = QLocale::system().name();
+      language_underscore = language_underscore.replace(u'-', u'_');
+      languages << language_underscore;
     }
-    else {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
-      language = system_languages.first();
-#else
-      language = system_languages.first();
-      language = language.replace(u'-', u'_');
 #endif
-    }
+  }
+
+  if (languages.isEmpty()) {
+    languages << QLocale::system().name();
   }
 
   ScopedPtr<Translations> translations(new Translations);
 
-  translations->LoadTranslation(u"qt"_s, QLibraryInfo::path(QLibraryInfo::TranslationsPath), language);
+  for (const QString &language : std::as_const(languages)) {
-  translations->LoadTranslation(u"strawberry"_s, u":/i18n"_s, language);
+    if (translations->LoadTranslation(u"qt"_s, QLibraryInfo::path(QLibraryInfo::TranslationsPath), language)) {
-  translations->LoadTranslation(u"strawberry"_s, QStringLiteral(TRANSLATIONS_DIR), language);
+      break;
-  translations->LoadTranslation(u"strawberry"_s, QCoreApplication::applicationDirPath(), language);
+    }
-  translations->LoadTranslation(u"strawberry"_s, QDir::currentPath(), language);
+  }
+
+  static const QStringList language_paths = QStringList() << u":/i18n"_s
+                                                          << QStringLiteral(TRANSLATIONS_DIR)
+                                                          << QCoreApplication::applicationDirPath()
+                                                          << QDir::currentPath();
+
+  for (const QString &language : std::as_const(languages)) {
+    bool language_loaded = false;
+    for (const QString &language_path : language_paths) {
+      if (translations->LoadTranslation(u"strawberry"_s, language_path, language)) {
+        language_loaded = true;
+        break;
+      }
+    }
+    if (language_loaded) {
+      break;
+    }
+  }
 
 #  ifdef HAVE_QTSPARKLE
-  qtsparkle::LoadTranslations(language);
+  if (!languages.isEmpty()) {
+    qtsparkle::LoadTranslations(languages.first());
+  }
 #  endif
 
-#endif
+#endif  // HAVE_TRANSLATIONS
 
   Application app;