Ticket #15906: 15906.diff

wp-admin/includes/plugin.php

@@ -779 +779 @@
         if ( ! file_exists(WP_PLUGIN_DIR . '/' . $plugin) )
                 return new WP_Error('plugin_not_found', __('Plugin file does not exist.'));
 
-        $installed_plugins = get_plugins();
+        $installed_plugins = apply_filters( 'all_plugins', get_plugins() );
         if ( ! isset($installed_plugins[$plugin]) )
                 return new WP_Error('no_plugin_header', __('The plugin does not have a valid header.'));
         return 0;