On Tue, 30 Dec 2008, demerphq wrote:
2008/12/30 Asheesh Laroia <asheesh@xxxxxxxxxxx>:
I ask about this because I'm using git to track email in Maildir
repositories, and in that vein I'm getting bitten by git's removal of
empty directories.
Add a .exists to each directory. There is precedent for such an
approach in other systems.
Delivering mail into a Maildir is a three-step process. Let's say
we are delivering to a Maildir spool stored in ~/Maildir.
(1)
The message is written out to ~/Maildir/tmp/some_filename.
(2)
When the message is complete, it is rename()d to
~/Maildir/new/some_name.
(3)
When a mail user agent reads the Maildir spool, it checks new/ for new
mail. If there is a message there, it renames it to
~/Maildir/cur/some_other_filename and announces to the user, "You've got
mail!"
So, let's say I take your suggestion.
$ touch ~/Maildir/new/.exists
$ git add ~/Maildir/new/.exists && git commit -m "La di da"
Now a spec-compliant Maildir user agent will attempt to deliver this new
"email message" of zero bytes into the mail spool and assign it a message
UID. Doing so will remove it from Maildir/new.
Then I do "git pull" to get the new messages from my mail server's Maildir
repository for my email. This causes git read-tree to eventually be run.
If the new tree has no unprocessed email, git runs rmdir() on
~/Maildir/new/.
Now if I want to write a new email to ~/Maildir/ (such as due to copying
an email from another folder), the Maildir user agent suddenly finds
itself in a strange place: new/ does not exist, violating the definition
of a Maildir. This breaks mail processing for that ~/Maildir/ folder.
This is because git is removing these directories. There is a strict
incompatibility between git rmdir()ing empty directories behind my back
and Maildir systems.
I hope that explains the issue I face, both to Junio and to Yves.
Note that for me, there is no issue with how to handle merging of empty
directories, or what happens if these empty directories become files, or
which empty directories to keep around; if git just never rmdir()s any
directories for me, and otherwise acts identically to now, that would
solve my problem. I can look into preparing an RFC patch that creates a
mode like that.
-- Asheesh.
--
You will be the last person to buy a Chrysler.
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
