Filter duplicate language code and script in system locale restoration

The new system language design restricts multiple country/region locales
for the same language code. Therefore, the system language restoration
flow must apply the same restriction.

Bug: 403442408
Test: run the test
Flag: EXEMPT bugfix
Change-Id: I1287483fdb56a00029ae1b03c86425361d4cdd1d

2 files changed, 21 insertions, 2 deletions

diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsHelper.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsHelper.java
index ed11e12c32ff..2273b4f81eea 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsHelper.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsHelper.java
@@ -54,6 +54,7 @@ import com.android.settingslib.devicestate.DeviceStateRotationLockSettingsManage
 import java.io.FileNotFoundException;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
@@ -650,6 +651,10 @@ public class SettingsHelper {
      *   e.g. current locale "en-US,zh-CN" and backup locale "ja-JP,zh-Hans-CN,en-US" are merged to
      *   "en-US,zh-CN,ja-JP".
      *
+     * - Same language codes and scripts are dropped.
+     *   e.g. current locale "en-US, zh-Hans-TW" and backup locale "en-UK, en-GB, zh-Hans-HK" are
+     *   merged to "en-US, zh-Hans-TW".
+     *
      * - Unsupported locales are dropped.
      *   e.g. current locale "en-US" and backup locale "ja-JP,zh-CN" but the supported locales
      *   are "en-US,zh-CN", the merged locale list is "en-US,zh-CN".
@@ -683,13 +688,23 @@ public class SettingsHelper {
             filtered.add(locale);
         }
 
+        final HashSet<String> existingLanguageAndScript = new HashSet<>();
         for (int i = 0; i < restore.size(); i++) {
             final Locale restoredLocaleWithExtension = copyExtensionToTargetLocale(restoredLocale,
                     getFilteredLocale(restore.get(i), allLocales));
+
             if (restoredLocaleWithExtension != null) {
-                filtered.add(restoredLocaleWithExtension);
+                String language = restoredLocaleWithExtension.getLanguage();
+                String script = restoredLocaleWithExtension.getScript();
+
+                String restoredLanguageAndScript =
+                        script == null ? language : language + "-" + script;
+                if (existingLanguageAndScript.add(restoredLanguageAndScript)) {
+                    filtered.add(restoredLocaleWithExtension);
+                }
             }
         }
+
         if (filtered.size() == current.size()) {
             return current;  // Nothing added to current locale list.
         }
diff --git a/packages/SettingsProvider/test/src/com/android/providers/settings/SettingsHelperTest.java b/packages/SettingsProvider/test/src/com/android/providers/settings/SettingsHelperTest.java
index 40654b0e2f37..48c778542d66 100644
--- a/packages/SettingsProvider/test/src/com/android/providers/settings/SettingsHelperTest.java
+++ b/packages/SettingsProvider/test/src/com/android/providers/settings/SettingsHelperTest.java
@@ -388,7 +388,11 @@ public class SettingsHelperTest {
                         LocaleList.forLanguageTags("zh-Hant-TW"),  // current
                         new String[] { "fa-Arab-AF-u-nu-latn", "zh-Hant-TW" }));  // supported
 
-
+        assertEquals(LocaleList.forLanguageTags("en-US,zh-Hans-TW"),
+                SettingsHelper.resolveLocales(
+                        LocaleList.forLanguageTags("en-UK,en-GB,zh-Hans-HK"),  // restore
+                        LocaleList.forLanguageTags("en-US,zh-Hans-TW"),  // current
+                        new String[] { "en-US,zh-Hans-TW,en-UK,en-GB,zh-Hans-HK" }));  // supported
     }
 
     @Test