Ticket #38632: 38632.2.diff

src/wp-admin/includes/user.php

@@ -98 +98 @@
 
                 if ( isset( $_POST['locale'] ) ) {
                         $locale = sanitize_text_field( $_POST['locale'] );
-                        if ( ! in_array( $locale, get_available_languages(), true ) ) {
+                        if ( 'site-default' === $locale ) {
                                 $locale = '';
+                        } elseif ( ! in_array( $locale, get_available_languages(), true ) ) {
+                                $locale = 'en_US';
                         }
 
-                        $user->locale = ( '' === $locale ) ? 'en_US' : $locale;
+                        $user->locale = $locale;
                 }
         }
 

src/wp-admin/user-edit.php

@@ -284 +284 @@
                 $user_locale = $profileuser->locale;
 
                 if ( 'en_US' === $user_locale ) {
-                        $user_locale = false;
-                } elseif ( ! in_array( $user_locale, $languages, true ) ) {
-                        $user_locale = get_locale();
+                        $user_locale = '';
+                } elseif ( '' === $user_locale || ! in_array( $user_locale, $languages, true ) ) {
+                        $user_locale = 'site-default';
                 }
 
                 wp_dropdown_languages( array(
@@ -294 +294 @@
                         'id'                          => 'locale',
                         'selected'                    => $user_locale,
                         'languages'                   => $languages,
-                        'show_available_translations' => false
+                        'show_available_translations' => false,
+                        'show_site_locale_default'    => true
                 ) );
                 ?>
         </td>

src/wp-includes/l10n.php

@@ -1065 +1065 @@
  *     @type bool|int $echo                         Whether to echo the generated markup. Accepts 0, 1, or their
  *                                                  boolean equivalents. Default 1.
  *     @type bool     $show_available_translations  Whether to show available translations. Default true.
+ *     @type bool     $show_site_locale_default     Whether to show an option to fall back to the site's locale. Default false.
  * }
  * @return string HTML content
  */
@@ -1078 +1079 @@
                 'selected'     => '',
                 'echo'         => 1,
                 'show_available_translations' => true,
+                'show_site_locale_default'    => false,
         ) );
 
+        // English (United States) uses an empty string for the value attribute.
+        if ( 'en_US' === $args['selected'] ) {
+                $args['selected'] = '';
+        }
+
         $translations = $args['translations'];
         if ( empty( $translations ) ) {
                 require_once( ABSPATH . 'wp-admin/includes/translation-install.php' );
@@ -1122 +1129 @@
         if ( $translations_available ) {
                 $structure[] = '<optgroup label="' . esc_attr_x( 'Installed', 'translations' ) . '">';
         }
-        $structure[] = '<option value="" lang="en" data-installed="1">English (United States)</option>';
+
+        if ( $args['show_site_locale_default'] ) {
+                $structure[] = sprintf( '<option value="site-default" data-installed="1">%s</option>', _x( 'Site Default', 'default site language' ) );
+        }
+
+        $structure[] = sprintf(
+                '<option value="" lang="en" data-installed="1"%s>English (United States)</option>',
+                selected( '', $args['selected'], false )
+        );
+
         foreach ( $languages as $language ) {
                 $structure[] = sprintf(
                         '<option value="%s" lang="%s"%s data-installed="1">%s</option>',