Subject: Re: Maildir ordering in git-mailsplit (was: Using mutt as a git maintainer)

From: Richard Braun <[email-masked]>
Date: Sat, 7 Aug 2010 13:21:59 +0200

On Sat, Aug 07, 2010 at 08:13:39AM +0530, Ramkumar Ramachandra wrote:
> Hi Richard,
> 
> Ah, it looks like this problem went unnoticed probably because
> everyone uses mboxes. One possible solution would be to teach
> `git-mailsplit` to order the emails correctly. You can reply with an
> RFC patch; I've CC'ed the Git list on this email.

Well, if everybody else has survived for five years with mbox patch
series, I guess I can do that too. With some not-so-difficult work, I
managed to have Mutt do what I wanted (that is, saving patch series in
mbox files in one macro and keep everything else with Maildir folders
untouched).

After some digging in the code, it doesn't look like a git issue. When
a Maildir folder is processed, its entries are actually sorted, unlike
what I first thought. populate_maildir_list() calls string_list_insert()
(in string-list.c) which does insertion sort through its static
add_entry() and get_entry_index() functions which use a bare strcmp() to
compare file names (it was path-list.c back in Git 1.5, same code).
When copying a threaded patch series in a Maildir folder with Mutt, here
are the names created:
1281177008.8677_101.myhostname:2,
1281177008.8677_103.myhostname:2,
1281177008.8677_105.myhostname:2,
1281177008.8677_107.myhostname:2,
1281177008.8677_109.myhostname:2,
1281177008.8677_111.myhostname:2,
1281177008.8677_113.myhostname:2,
1281177008.8677_11.myhostname:2,
1281177008.8677_13.myhostname:2,
1281177008.8677_15.myhostname:2,
1281177008.8677_17.myhostname:2,
1281177008.8677_19.myhostname:2,
1281177008.8677_1.myhostname:2,
1281177008.8677_21.myhostname:2,
1281177008.8677_23.myhostname:2,

And for such names, git am determines that e.g.
"1281177008.8677_107.myhostname:2", should be applied before
"1281177008.8677_17.myhostname:2,", which is obviously wrong.

I'm not sure about what depends on string-list.c, but based on the
output of a raw grep, it doesn't seem like a good idea to change the
way strings are sorted, especially if almost noone uses Maildir for
patch series. The best solution IMO would be a Mutt hook to alter the
file names or something like that. A good workaround is configuring it
to use mbox as the default format and keep existing folders as Maildirs
(that's what I'm doing now). I guess the only file to patch in any case
is Documentation/SubmittingPatches, adding an entry for Mutt in the MUA
hints part (if possible with the renaming hook if someone knows how to
do that - I'll search a bit on my side - or with an explanation of the
issue and the simple mbox workaround).

-- 
Richard Braun