Android: use BCP 47 tag to create a correct Locale for QTimeZone::displayName()

Before the patch we tried to create a java Locale object by passing the
human-readable language, territory and variant strings. However, the
Locale constructor accepts ISO-defined codes.

Fix it by using a factory method Locale.forLanguageTag() [0] that
constructs a Java Locale object based on BCP 47 tag.

[0]: https://developer.android.com/reference/java/util/Locale#forLanguageTag(java.lang.String)

Fixes: QTBUG-101460
Change-Id: If414c66cf0e5b7e8299ffc3a6038b6f9eb79d5ec
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit 44f3fe1cf4e2319e012207eba3afe7adfe09cad6)

2 files changed, 55 insertions, 11 deletions

diff --git a/src/corelib/time/qtimezoneprivate_android.cpp b/src/corelib/time/qtimezoneprivate_android.cpp
index 9ba6f58072..3829ff3bb5 100644
--- a/src/corelib/time/qtimezoneprivate_android.cpp
+++ b/src/corelib/time/qtimezoneprivate_android.cpp
@@ -88,17 +88,10 @@ QAndroidTimeZonePrivate::~QAndroidTimeZonePrivate()
 static QString getDisplayName(QJniObject zone, jint style, jboolean dst,
                                         const QLocale &locale)
 {
-    QJniObject jlanguage
-        = QJniObject::fromString(QLocale::languageToString(locale.language()));
-    QJniObject jterritory
-        = QJniObject::fromString(QLocale::territoryToString(locale.territory()));
-    QJniObject
-        jvariant = QJniObject::fromString(QLocale::scriptToString(locale.script()));
-    QJniObject jlocale("java.util.Locale",
-                       "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V",
-                       jlanguage.object<jstring>(),
-                       jterritory.object<jstring>(),
-                       jvariant.object<jstring>());
+    QJniObject jbcpTag = QJniObject::fromString(locale.bcp47Name());
+    QJniObject jlocale = QJniObject::callStaticObjectMethod(
+                "java/util/Locale", "forLanguageTag", "(Ljava/lang/String;)Ljava/util/Locale;",
+                jbcpTag.object<jstring>());
 
     return zone.callObjectMethod("getDisplayName",
                                  "(ZILjava/util/Locale;)Ljava/lang/String;",
diff --git a/tests/auto/corelib/time/qtimezone/tst_qtimezone.cpp b/tests/auto/corelib/time/qtimezone/tst_qtimezone.cpp
index 12370f9e14..c4a7c3cf33 100644
--- a/tests/auto/corelib/time/qtimezone/tst_qtimezone.cpp
+++ b/tests/auto/corelib/time/qtimezone/tst_qtimezone.cpp
@@ -75,6 +75,8 @@ private Q_SLOTS:
     void macTest();
     void darwinTypes();
     void winTest();
+    void localeSpecificDisplayName_data();
+    void localeSpecificDisplayName();
 
 private:
     void printTimeZone(const QTimeZone &tz);
@@ -1450,6 +1452,55 @@ void tst_QTimeZone::winTest()
 #endif // QT_BUILD_INTERNAL && USING_WIN_TZ
 }
 
+void tst_QTimeZone::localeSpecificDisplayName_data()
+{
+#ifdef USING_WIN_TZ
+    QSKIP("MS backend does not use locale parameter");
+#endif
+    QTest::addColumn<QByteArray>("zoneName");
+    QTest::addColumn<QLocale>("locale");
+    QTest::addColumn<QTimeZone::TimeType>("timeType");
+    QTest::addColumn<QString>("expectedName");
+
+    QStringList names;
+    QLocale locale;
+    // Pick a non-system locale; German or French
+    if (QLocale::system().language() != QLocale::German) {
+        locale = QLocale(QLocale::German);
+        names << QString("Mitteleurop\u00e4ische Normalzeit")
+              << QString("Mitteleurop\u00e4ische Sommerzeit");
+    } else {
+        locale = QLocale(QLocale::French);
+        names << QString("heure normale d\u2019Europe centrale")
+              << QString("heure d\u2019\u00E9t\u00E9 d\u2019Europe centrale");
+    }
+
+    qsizetype index = 0;
+    QTest::newRow("Berlin, standard time")
+            << QByteArray("Europe/Berlin") << locale << QTimeZone::StandardTime
+            << names.at(index++);
+
+    QTest::newRow("Berlin, summer time")
+            << QByteArray("Europe/Berlin") << locale << QTimeZone::DaylightTime
+            << names.at(index++);
+}
+
+void tst_QTimeZone::localeSpecificDisplayName()
+{
+    // This test checks that QTimeZone::displayName() correctly uses the
+    // specified locale, NOT the system locale (see QTBUG-101460).
+    QFETCH(QByteArray, zoneName);
+    QFETCH(QLocale, locale);
+    QFETCH(QTimeZone::TimeType, timeType);
+    QFETCH(QString, expectedName);
+
+    QTimeZone zone(zoneName);
+    QVERIFY(zone.isValid());
+
+    const QString localeName = zone.displayName(timeType, QTimeZone::LongName, locale);
+    QCOMPARE(localeName, expectedName);
+}
+
 #ifdef QT_BUILD_INTERNAL
 // Test each private produces the same basic results for CET
 void tst_QTimeZone::testCetPrivate(const QTimeZonePrivate &tzp)