From 5b5619f717be2a712c05d6c63a0ca4184f263aee Mon Sep 17 00:00:00 2001
From: Petri Lehtinen <petri@digip.org>
Date: Fri, 29 Jun 2012 15:09:12 +0300
Subject: [PATCH] #5346: Preserve permissions of mbox, MMDF and Babyl mailbox
 files on flush()

---
 Lib/mailbox.py           |  3 +++
 Lib/test/test_mailbox.py | 17 +++++++++++++++++
 Misc/NEWS                |  3 +++
 3 files changed, 23 insertions(+)

diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index 73c43e22f7a..8b00460ec6d 100644
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -691,6 +691,9 @@ class _singlefileMailbox(Mailbox):
         _sync_close(new_file)
         # self._file is about to get replaced, so no need to sync.
         self._file.close()
+        # Make sure the new file's mode is the same as the old file's
+        mode = os.stat(self._path).st_mode
+        os.chmod(new_file.name, mode)
         try:
             os.rename(new_file.name, self._path)
         except OSError as e:
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index d8dca1d86cb..9f1fdad383c 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -966,6 +966,23 @@ class _TestSingleFile(TestMailbox):
         self._box = self._factory(self._path)
         self.assertEqual(len(self._box), 1)
 
+    def test_permissions_after_flush(self):
+        # See issue #5346
+
+        # Make the mailbox world writable. It's unlikely that the new
+        # mailbox file would have these permissions after flush(),
+        # because umask usually prevents it.
+        mode = os.stat(self._path).st_mode | 0o666
+        os.chmod(self._path, mode)
+
+        self._box.add(self._template % 0)
+        i = self._box.add(self._template % 1)
+        # Need to remove one message to make flush() create a new file
+        self._box.remove(i)
+        self._box.flush()
+
+        self.assertEqual(os.stat(self._path).st_mode, mode)
+
 
 class _TestMboxMMDF(_TestSingleFile):
 
diff --git a/Misc/NEWS b/Misc/NEWS
index 242b8f76d1a..99515c06392 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -81,6 +81,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #5346: Preserve permissions of mbox, MMDF and Babyl mailbox
+  files on flush().
+
 - Issue #10571: Fix the "--sign" option of distutils' upload command.
   Patch by Jakub Wilk.