Ticket #29487: 29487.2.diff

src/wp-admin/install.php

@@ -184 +184 @@
 $langugage = '';
 if ( ! empty( $_REQUEST['language'] ) ) {
         $langugage = preg_replace( '/[^a-zA-Z_]/', '', $_REQUEST['language'] );
+} elseif ( isset( $GLOBALS['wp_local_package'] ) ) {
+        $language = $GLOBALS['wp_local_package'];
 }
 
 switch($step) {

src/wp-admin/setup-config.php

@@ -90 +90 @@
 $language = '';
 if ( ! empty( $_REQUEST['language'] ) ) {
         $language = preg_replace( '/[^a-zA-Z_]/', '', $_REQUEST['language'] );
+} elseif ( isset( $GLOBALS['wp_local_package'] ) ) {
+        $language = $GLOBALS['wp_local_package'];
 }
+
 switch($step) {
         case -1:
                 if ( wp_can_install_language_pack() && empty( $language ) && ( $languages = wp_get_available_translations() ) ) {