Skip endonym in linguist settings list when not available

The settings dialog iterates all members of the QLocale::Language
enum, producing an entry for each. It tried to add the endonym of each
language to its entry; however, QLocale(language) gets the default
locale if there is no CLDR data for the given language; and the
default locale's endonym is no use to us. So don't attempt to include
the endonym of a language unless the locale from which we get it
actually does use the requested language. Also mention why English
skips its endonym.

Fixes: QTBUG-102832
Change-Id: Ia4583727beb247e4775f443d98089db3f02a17d2
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
(cherry picked from commit b30768f7714141158b4fa7afd3ae2ad5ca68dceb)
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 11 insertions, 9 deletions

diff --git a/src/linguist/linguist/translationsettingsdialog.cpp b/src/linguist/linguist/translationsettingsdialog.cpp
index 7a1a53585..dc523f8f4 100644
--- a/src/linguist/linguist/translationsettingsdialog.cpp
+++ b/src/linguist/linguist/translationsettingsdialog.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Linguist of the Qt Toolkit.
@@ -41,14 +41,16 @@ TranslationSettingsDialog::TranslationSettingsDialog(QWidget *parent)
     m_ui.setupUi(this);
 
     for (int i = QLocale::C + 1; i < QLocale::LastLanguage; ++i) {
-        QString lang = QLocale::languageToString(QLocale::Language(i));
-        auto loc = QLocale(QLocale::Language(i));
-        if (loc.language() != QLocale::English) {
-            QString nln = loc.nativeLanguageName();
-            if (!nln.isEmpty()) {
-                //: <english> (<endonym>)  (language and country names)
-                lang = tr("%1 (%2)").arg(lang, nln);
-            }
+        const auto language = QLocale::Language(i);
+        QString lang = QLocale::languageToString(language);
+        const auto loc = QLocale(language);
+        // Languages for which we have no data get mapped to the default locale;
+        // its endonym is unrelated to the language requested. For English, the
+        // endonym is the name we already have; don't repeat it.
+        if (loc.language() == language && language != QLocale::English) {
+            const QString native = loc.nativeLanguageName();
+            if (!native.isEmpty()) //: <english> (<endonym>)  (language names)
+                lang = tr("%1 (%2)").arg(lang, native);
         }
         m_ui.srcCbLanguageList->addItem(lang, QVariant(i));
     }