Ticket #20441: 20441.patch

wp-admin/includes/plugin-install.php

@@ -184 +184 @@
 
         //Check to see if this plugin is known to be installed, and has an update awaiting it.
         $update_plugins = get_site_transient('update_plugins');
-        if ( is_object( $update_plugins ) ) {
+        if ( isset( $update_plugins->response ) ) {
                 foreach ( (array)$update_plugins->response as $file => $plugin ) {
                         if ( $plugin->slug === $api->slug ) {
                                 $status = 'update_available';