From ed52a20c6eb451cd8827e3901f115709980edaae Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 16 Feb 1999 15:10:12 +0000
Subject: [PATCH] In open_ftp(), check that retrlen is not None before using it
 in a %d format!

---
 Lib/urllib.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/urllib.py b/Lib/urllib.py
index d175eef91b..d37906c0b2 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -387,7 +387,7 @@ class URLopener:
 				   value in ('a', 'A', 'i', 'I', 'd', 'D'):
 					type = string.upper(value)
                         (fp, retrlen) = self.ftpcache[key].retrfile(file, type)
-                        if retrlen >= 0:
+                        if retrlen is not None and retrlen >= 0:
                             import mimetools, StringIO
                             headers = mimetools.Message(StringIO.StringIO(
                                 'Content-Length: %d\n' % retrlen))
-- 
2.50.0