The Maildir specification doesn't seem to say anything about this
situation, and it can happen if you're keeping a Maildir mailbox in
Subversion (.svn directories) or some similar system. The patch just
ignores directories in the cur/, new/, tmp/ folders.
Add length checking to single-file mailbox formats: before doing a
flush() on a mailbox, seek to the end and verify its length is
unchanged, raising ExternalClashError if the file's length has
changed.
This fix avoids potential data loss if some other process appends to
the mailbox file after the table of contents has been generated;
instead of overwriting the modified file, you'll get the exception.
I also noticed that the self._lookup() call in self.flush() wasn't
necessary (everything that sets self._pending to True also calls
self.lookup()), and replaced it by an assertion.
2.5 backport candidate.
This change looks massive but it's mostly a re-indenting after
removing some try...finally blocks.
Also adds a test case that does a pack() while the mailbox is locked; this
test would have turned up bugs in the original code on some platforms.
In both nmh and GNU Mailutils' implementation of MH-format mailboxes,
no locking is done of individual message files when renaming them.
The original mailbox.py code did do locking, which meant that message
files had to be opened. This code was buggy on certain platforms
(found through reading the code); there were code paths that closed
the file object and then called _unlock_file() on it.
Will backport to 25-maint once I see how the buildbots react to this patch.
Two changes:
Where possible, use link()/remove() to move files into a directory; this
makes it easier to avoid overwriting an existing file.
Use _create_carefully() to create files in tmp/, which uses O_EXCL.
Backport candidate.
remove the flock() calls.
On FreeBSD, the two methods lockf() and flock() end up using the same
mechanism and the second one fails. A Linux man page claims that the
two methods are orthogonal (so locks acquired one way don't interact
with locks acquired the other way) but that clearly must be false.
the 2005 Summer of Code).
The revision adds a number of new mailbox classes that support adding
and removing messages; these classes also support mailbox locking and
default to using email.Message instead of rfc822.Message.
The old mailbox classes are largely left alone for backward compatibility.
The exception is the Maildir class, which was present in the old module
and now inherits from the new classes. The Maildir class's interface
is pretty simple, though, so I think it'll be compatible with existing
code.
(The change to the NEWS file also adds a missing word to a different
news item, which unfortunately required rewrapping the line.)
