Ticket #43700: 43700.2.diff

src/wp-admin/css/login.css

@@ -232 +232 @@
 }
 
 .login #nav,
-.login #backtoblog {
+.login #backtoblog,
+.language-switcher {
         font-size: 13px;
         padding: 0 24px 0;
 }
@@ -328 +329 @@
         margin: 0;
 }
 
+#language-switcher {
+    padding: 0;
+    background: none;
+    box-shadow: none;
+}
+
+#language-switcher select {
+    height: 30px;
+}
+
+.screen-reader-text {
+    border: 0;
+    clip: rect(1px, 1px, 1px, 1px);
+    -webkit-clip-path: inset(50%);
+    clip-path: inset(50%);
+    height: 1px;
+    margin: -1px;
+    overflow: hidden;
+    padding: 0;
+    position: absolute;
+    width: 1px;
+    word-wrap: normal !important;
+}
+
+.language-switcher {
+    width: 320px;
+    margin: 0 auto 24px;
+    box-sizing: border-box;
+}
+
+.language-switcher label {
+    margin-right: .5em;
+}
+
+.language-switcher .dashicons {
+    line-height: 30px;
+}
+
 @-ms-viewport {
         width: device-width;
 }

src/wp-includes/l10n.php

@@ -143 +143 @@
                 $determined_locale = get_user_locale();
         }
 
-        if ( ! empty( $_GET['wp_lang'] ) && ! empty( $GLOBALS['pagenow'] ) && 'wp-login.php' === $GLOBALS['pagenow'] ) {
-                $determined_locale = sanitize_text_field( $_GET['wp_lang'] );
+        $wp_lang = '';
+
+        if ( ! empty( $_GET['wp_lang'] ) ) {
+                $wp_lang = $_GET['wp_lang'];
+        } elseif ( ! empty( $_COOKIE['wp_lang'] ) ) {
+                $wp_lang = $_COOKIE['wp_lang'];
+        }
+
+        if ( ! empty( $wp_lang ) && ! empty( $GLOBALS['pagenow'] ) && 'wp-login.php' === $GLOBALS['pagenow'] ) {
+                $determined_locale = sanitize_text_field( $wp_lang );
         }
 
         /**
@@ -1397 +1405 @@
  * @since 4.3.0 Introduced the `echo` argument.
  * @since 4.7.0 Introduced the `show_option_site_default` argument.
  * @since 5.1.0 Introduced the `show_option_en_us` argument.
+ * @since x.x.x Introduced the `explicit_option_en_us` argument.
  *
  * @see get_available_languages()
  * @see wp_get_available_translations()
@@ -1416 +1425 @@
  *     @type bool     $show_available_translations  Whether to show available translations. Default true.
  *     @type bool     $show_option_site_default     Whether to show an option to fall back to the site's locale. Default false.
  *     @type bool     $show_option_en_us            Whether to show an option for English (United States). Default true.
+ *     @type bool     $explicit_option_en_us        Whether the English (United States) option uses an explict value of en_US
+ *                                                  instead of an empty value. Default false.
  * }
  * @return string HTML content
  */
@@ -1433 +1444 @@
                         'show_available_translations' => true,
                         'show_option_site_default'    => false,
                         'show_option_en_us'           => true,
+                        'explicit_option_en_us'       => false,
                 )
         );
 
@@ -1442 +1454 @@
         }
 
         // English (United States) uses an empty string for the value attribute.
-        if ( 'en_US' === $parsed_args['selected'] ) {
+        if ( 'en_US' === $parsed_args['selected'] && ! $parsed_args['explicit_option_en_us'] ) {
                 $parsed_args['selected'] = '';
         }
 
@@ -1497 +1509 @@
         }
 
         if ( $parsed_args['show_option_en_us'] ) {
+                $value = ( $parsed_args['explicit_option_en_us'] ) ? 'en_US' : '';
                 $structure[] = sprintf(
-                        '<option value="" lang="en" data-installed="1"%s>English (United States)</option>',
+                        '<option value="%s" lang="en" data-installed="1"%s>English (United States)</option>',
+                        esc_attr( $value ),
                         selected( '', $parsed_args['selected'], false )
                 );
         }

src/wp-login.php

@@ -291 +291 @@
         </div><?php // End of <div id="login"> ?>
 
         <?php
+    $languages = get_available_languages();
+
+    if ( ! empty( $languages ) ) { ?>
+
+        <div class="language-switcher">
+                <form id="language-switcher" action="" method="GET">
+
+                <label for="language-switcher-locales">
+                        <span aria-hidden="true" class="dashicons dashicons-translation"></span>
+                        <span class="screen-reader-text"><?php _e( 'Language' ); ?></span>
+                </label>
+
+                <?php
+                        $args = array(
+                                'id'                          => 'language-switcher-locales',
+                                'name'                        => 'wp_lang',
+                                'selected'                    => determine_locale(),
+                                'show_available_translations' => false,
+                                'explicit_option_en_us'       => true,
+                                'languages'                   => $languages,
+                        );
+
+                        /**
+                         * Filters default arguments for the Languages dropdown on the login screen.
+                         *
+                         * @since x.x.x
+                         *
+                         * @param Array $args Arguments for the Languages dropdown on the login screen.
+                         */
+                        wp_dropdown_languages( apply_filters( 'wp_login_language_switcher_args', $args ) );
+                ?>
+
+                <?php if ( $interim_login ) { ?>
+                        <input type="hidden" name="interim-login" value="1" />
+                <?php } ?>
+
+                <?php if ( isset( $_GET['redirect_to'] ) && '' !== $_GET['redirect_to'] ) { ?>
+                        <input type="hidden" name="redirect_to" value="<?php echo esc_url_raw( $_GET['redirect_to'] ) ?>" />
+                <?php } ?>
+
+                <?php if ( isset( $_GET['action'] ) && '' !== $_GET['action'] ) { ?>
+                        <input type="hidden" name="action" value="<?php echo sanitize_text_field( $_GET['action'] ) ?>" />
+                <?php } ?>
+
+                </form>
+        </div>
+
+        <script>
+        var switcherForm  = document.getElementById( 'language-switcher' );
+        var localesSelect = document.getElementById( 'language-switcher-locales' );
+        localesSelect.addEventListener( 'change', function() {
+                switcherForm.submit()
+        } );
+        </script>
+
+<?php } ?>
+
+        <?php
 
         if ( ! empty( $input_id ) ) {
                 ?>
@@ -513 +571 @@
         setcookie( TEST_COOKIE, 'WP Cookie check', 0, SITECOOKIEPATH, COOKIE_DOMAIN, $secure );
 }
 
+if ( isset( $_GET['wp_lang'] ) ) {
+        setcookie( 'wp_lang', $_GET['wp_lang'], 0, COOKIEPATH, COOKIE_DOMAIN, $secure );
+}
+
 /**
  * Fires when the login form is initialized.
  *