Ticket #24747: 24747.patch

wp-admin/includes/plugin-install.php

@@ -229 +229 @@
                                 if ( current_user_can('install_plugins') )
                                         $url = wp_nonce_url(self_admin_url('update.php?action=install-plugin&plugin=' . $api->slug), 'install-plugin_' . $api->slug);
                         } else {
-                                $key = array_shift( $key = array_keys($installed_plugin) ); //Use the first plugin regardless of the name, Could have issues for multiple-plugins in one directory if they share different version numbers
+                                $key = array_keys( $installed_plugin );
+                                $key = array_shift( $key ); //Use the first plugin regardless of the name, Could have issues for multiple-plugins in one directory if they share different version numbers
                                 if ( version_compare($api->version, $installed_plugin[ $key ]['Version'], '=') ){
                                         $status = 'latest_installed';
                                 } elseif ( version_compare($api->version, $installed_plugin[ $key ]['Version'], '<') ) {