Ticket #29397: 29397.2.patch

src/wp-admin/includes/translation-install.php

@@ -204 +204 @@
         $skin = new Automatic_Upgrader_Skin;
         $upgrader = new Language_Pack_Upgrader( $skin );
         $translation->type = 'core';
-        /**
-         * @todo failures (such as non-direct FS)
-         */
         $result = $upgrader->upgrade( $translation, array( 'clear_update_cache' => false ) );
+
+        if ( ! $result || is_wp_error( $result ) ) {
+                return false;
+        }
+
         return $translation->language;
 }
+
+/**
+ * Check if WordPress has access to the filesystem without asking for
+ * credentials.
+ *
+ * @since 4.0.0
+ *
+ * @return bool Returns true on success, false on failure.
+ */
+function wp_can_install_language_pack() {
+        if ( defined( 'DISALLOW_FILE_MODS' ) && DISALLOW_FILE_MODS ) {
+                return false;
+        }
+
+        require_once ABSPATH . 'wp-admin/includes/class-wp-upgrader.php';
+        $skin = new Automatic_Upgrader_Skin;
+        $upgrader = new Language_Pack_Upgrader( $skin );
+
+        $check = $upgrader->fs_connect( array( WP_CONTENT_DIR, WP_LANG_DIR ) );
+
+        if ( ! $check || is_wp_error( $check ) ) {
+                return false;
+        }
+
+        return true;
+}

src/wp-admin/install.php

@@ -189 +189 @@
 switch($step) {
         case 0: // Step 0
 
-                if ( empty( $langugage ) && ( $languages = wp_get_available_translations() ) ) {
+                if ( wp_can_install_language_pack() && empty( $langugage ) && ( $languages = wp_get_available_translations() ) ) {
                         display_header( 'language-chooser' );
                         echo '<form id="setup" method="post" action="?step=1">';
                         wp_install_language_form( $languages );

src/wp-admin/setup-config.php

@@ -95 +95 @@
 }
 switch($step) {
         case -1:
-                if ( empty( $language ) && ( $languages = wp_get_available_translations() ) ) {
+                if ( wp_can_install_language_pack() && empty( $language ) && ( $languages = wp_get_available_translations() ) ) {
                         setup_config_display_header( 'language-chooser' );
                         echo '<form id="setup" method="post" action="?step=0">';
                         wp_install_language_form( $languages );