diff -r c177faafec51 -r c6a4d267fe88 Lib/urllib/request.py
--- a/Lib/urllib/request.py	Thu Mar 24 22:27:01 2011 +0800
+++ b/Lib/urllib/request.py	Thu Mar 24 23:21:46 2011 +0800
@@ -543,8 +543,11 @@
         else:
             return
 
-        # fix a possible malformed URL
         urlparts = urlparse(newurl)
+
+        if not urlparts.scheme in ('http','https','ftp'):
+            return
+
         if not urlparts.path:
             urlparts = list(urlparts)
             urlparts[2] = "/"