commit 0f4ed2cdc6e7887153c481f4c7298bc35e219d84
author Serhiy Storchaka <storchaka@gmail.com> Sun Jan 01 19:04:09 2017 +0200
committer Serhiy Storchaka <storchaka@gmail.com> Sun Jan 01 19:04:09 2017 +0200
tree b32c0db490b4136dc6ededa8eee3aeb9aa28f1f8
parent c644d53acfa0e4f1fe470430e15e69717da4f264

Issue #29094: Offsets in a ZIP file created with extern file object and modes
"w" now are relative to the start of the file.

Lib/zipfile.py

diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 1d10650..cc9f2e6 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -772,7 +772,7 @@
                 # set the modified flag so central directory gets written
                 # even if no files are added to the archive
                 self._didModify = True
-                self._start_disk = self.fp.tell()
+                self._start_disk = 0
             elif key == 'a':
                 try:
                     # See if file is a zip file