Index: includes/module.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/module.inc,v
retrieving revision 1.161
diff -u -p -r1.161 module.inc
--- includes/module.inc	16 Oct 2009 03:01:54 -0000	1.161
+++ includes/module.inc	27 Oct 2009 10:42:10 -0000
@@ -62,6 +62,8 @@ function module_list($refresh = FALSE, $
       }
       foreach ($result as $module) {
         if (file_exists($module->filename)) {
+          // First call drupal_get_filename() to prime the static cache for
+          // later lookups of the module path. For example by drupal_load().
           drupal_get_filename('module', $module->name, $module->filename);
           $list[$module->name] = $module->name;
         }