commit 44989bc2696320cf55ae6f329aaf58edd49d792a
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sat Sep 22 11:03:04 2018 -0700
committer Serhiy Storchaka <storchaka@gmail.com> Sat Sep 22 21:03:04 2018 +0300
tree 7151eeca2af51b3fae90de93c92d2e364dfb4352
parent 0c076caaa82a9c6596e1fe1dbe6384d53f30a1a3

bpo-34472: Add data descriptor signature to zipfile (GH-8871) (GH-9399)

This makes streamed zips compatible with MacOS Archive Utility and
other applications.
(cherry picked from commit 4ba3b50bfe6d50cd82d208023ea23e203ab50589)

Co-authored-by: Silas Sewell <silas@sewell.org>

Lib/zipfile.py

diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 9f88512..a438785 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -159,6 +159,8 @@
 _CD64_DIRECTORY_SIZE = 8
 _CD64_OFFSET_START_CENTDIR = 9
 
+_DD_SIGNATURE = 0x08074b50
+
 _EXTRA_FIELD_STRUCT = struct.Struct('<HH')
 
 def _strip_extra(extra, xids):
@@ -1114,8 +1116,8 @@
         # Write updated header info
         if self._zinfo.flag_bits & 0x08:
             # Write CRC and file sizes after the file data
-            fmt = '<LQQ' if self._zip64 else '<LLL'
-            self._fileobj.write(struct.pack(fmt, self._zinfo.CRC,
+            fmt = '<LLQQ' if self._zip64 else '<LLLL'
+            self._fileobj.write(struct.pack(fmt, _DD_SIGNATURE, self._zinfo.CRC,
                 self._zinfo.compress_size, self._zinfo.file_size))
             self._zipfile.start_dir = self._fileobj.tell()
         else: