From 5b90f5de26fc6a659e8bb2224c31af89c0b71d0b Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sun, 1 Feb 2015 19:01:10 +0200
Subject: [PATCH] Don't seek to the start of the file when open ZipFile with
 the 'w' mode (regression introduced in issue #14099).

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

diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 845c6a96fc6..8c2950f5333 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -1002,7 +1002,7 @@ class ZipFile:
                 # set the modified flag so central directory gets written
                 # even if no files are added to the archive
                 self._didModify = True
-                self.start_dir = 0
+                self.start_dir = self.fp.tell()
             elif mode == 'a':
                 try:
                     # See if file is a zip file