keymanapp · darcywong00 · May 11, 2026 · May 13, 2026 · May 13, 2026 · May 13, 2026
diff --git a/_includes/2020/templates/Head.php b/_includes/2020/templates/Head.php
@@ -39,10 +39,7 @@ static function render($fields = []) {
       // Redirect to /en/... if not a supported locale; this needs to be emitted
       // as a HTTP header before first content byte.
       if(Locale::invalidLocale()) {
-        if(preg_match('/^\\/[^\/]+\\/(.+)$/', $_SERVER['REQUEST_URI'], $matches)) {
-          header("Location: /" . Locale::DEFAULT_LOCALE . "/" . $matches[1]);
-          return;
-        }
+        Locale::redirectLocale();
       }
 ?><!DOCTYPE html>
 <html lang='<?=$fields->pageLocale?>'>

diff --git a/_includes/2020/templates/Menu.php b/_includes/2020/templates/Menu.php
@@ -35,7 +35,7 @@ public static function render(array $fields): void {
 
     /**
      * Modify link of the current URL for a given UI language.
-     * Skip if current URL isn't localized (e.g. _legacy)
+     * If current URL isn't localized (e.g. _legacy or no BCP-47 in path), return original URL
      * @param language - language tag to use
      * @return string - modified URL
      */
@@ -45,14 +45,16 @@ private static function change_ui_language($language): string {
       $parts = parse_url($url);
 
       $path = '';
-      // Replace language if current language in path is valid BCP-47
+      // Replace $path[1] if a fallback locale of $language is in DISPLAY_NAMES
       if (!empty($parts['path'])) {
         $path = explode("/", $parts['path']);
-        if ($path[1] == Locale::pageLocale()) {
+        $matchingLanguages = isset($path[1]) ? 
+          array_intersect(Locale::calculateFallbackLocales($path[1]), array_keys(DISPLAY_NAMES)) : [];
+        if (count($matchingLanguages) > 0) {
           $path[1] = $language;
-        } else if (preg_match('/^\/(_legacy)\/.*$/i', $path[1], $matches)) {
+        } else if (preg_match('/^(?!_legacy|go|mac|web)([^\/]+)$/i', $path[1], $matches)) {
           // original URL didn't have a valid BCP-47, so insert new langage
-          // Skip for certain paths like: _legacy
+          // Skip for certain paths like: _legacy or 2-3 letter paths
           array_splice($path, 1, 0, $language);
         }
       }

diff --git a/_includes/locale/Locale.php b/_includes/locale/Locale.php
@@ -62,22 +62,39 @@ public static function invalidLocale() {
       return self::$invalidLocale;
     }
 
+    /**
+     * Redirect page to specified locale. Default to en
+     * @param $newLocale
+     */
+    public static function redirectLocale($newLocale = Locale::DEFAULT_LOCALE) {
+      if(preg_match('/^\\/[^\/]+\\/(.+)$/', $_SERVER['REQUEST_URI'], $matches)) {
+        header("Location: /" . $newLocale . "/" . $matches[1]);
+        return;
+      }
+    }
+
     /**
      * Set the current locale based on the first path component
      * /<locale>/rest/of/path for the current page URL
      */
     private static function setLocaleFromURL() {
       // First component of the URL is always the locale
-      if(preg_match('/^\\/(([a-z]{2,3})(-([A-Za-z]{4}))?(-([a-z]{2}|[0-9]{3}))?)\\//', $_SERVER['REQUEST_URI'], $matches)) {
-        if(!isset(DISPLAY_NAMES[$matches[1]])) {
+      if(preg_match('/^\/(([a-z]{2,3})(-([A-Z][a-z]{3}))?(-([A-Z]{2}|[0-9]{3}))?)\//', $_SERVER['REQUEST_URI'], $matches)) {
+        $fallbackLocales = self::calculateFallbackLocales($matches[1]);
+        if (isset($fallbackLocales[0])) {
+          $pageLocale = $fallbackLocales[0];
+          if ($pageLocale != $matches[1]) {
+            // Redirect if using a fallback locale
+            Locale::redirectLocale($pageLocale);
+          };
+        } else {
           // Note: this is an unsupported locale, so we'll end up redirecting in head.php to /en/...
           $pageLocale = Locale::DEFAULT_LOCALE;
           self::$invalidLocale = true;
-        } else {
-          $pageLocale = $matches[1];
         }
       } else {
         $pageLocale = Locale::DEFAULT_LOCALE;
+        // Don't set invalidLocale so pages like /_test/ work
       }
       self::setLocale($pageLocale);
     }
@@ -178,7 +195,7 @@ public static function definePageScope($define, $id) {
      * @param $locale - the locale to determine fallback locales
      * @return array of fallback locales
      */
-    private static function calculateFallbackLocales($locale) {
+    public static function calculateFallbackLocales($locale) {
       // Start with the given locale
       $fallback = [$locale];
 

diff --git a/build.sh b/build.sh
@@ -38,7 +38,7 @@ function preprocess_htaccess() {
   local locales localesregex
   locales=($(cat ./_includes/locale/locales.json | grep '"' | cut -d\" -f 2 -))
   localesregex=$(IFS=\| ; echo "${locales[*]}")
-  sed -e "s/@locales/${localesregex}/g" .htaccess.in >> .htaccess
+  sed -e "s/(@locales)/(([a-z]{2,3})(-([A-Z][a-z]{3}))?(-([A-Z]{2}|[0-9]{3}))?)/g" .htaccess.in >> .htaccess
 }
 
 function do_configure() {