? modules/path/example.patch
Index: modules/path/path.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/path/path.module,v
retrieving revision 1.138.2.3
diff -u -p -r1.138.2.3 path.module
--- modules/path/path.module	22 Nov 2008 10:49:15 -0000	1.138.2.3
+++ modules/path/path.module	30 Mar 2010 14:37:29 -0000
@@ -105,7 +105,7 @@ function path_set_alias($path = NULL, $a
     if ($alias == drupal_get_path_alias($path, $language)) {
       // There is already such an alias, neutral or in this language.
       // Update the alias based on alias; setting the language if not yet done.
-      db_query("UPDATE {url_alias} SET src = '%s', dst = '%s', language = '%s' WHERE dst = '%s'", $path, $alias, $language, $alias);
+      db_query("UPDATE {url_alias} SET src = '%s', dst = '%s', language = '%s' WHERE dst = '%s' AND src='%s'", $path, $alias, $language, $alias, $path);
     }
     else {
       // A new alias. Add it to the database.