From: Jonathan Nieder <jrnieder@gmail.com>
Date: Wed, 06 Apr 2011 22:12:05 GMT
Subject: Re: git: "git stash" changes owners and permissions
Message-ID: <20110406221205.GB2894@elie>
In-Reply-To: <7voc4jgig7.fsf@alter.siamese.dyndns.org>

Junio C Hamano wrote:

> How does this "rsync" solve "the wrong order" and "creates windows"
> problems?  It will update the paths in the order rsync happens to discover
> and there is a wondow between the time the first path is updated and the
> whole directory gets finally in sync.

All true.  It's a little better than "git checkout" because rsync
will stage files and then rename them into place rather than leaving
a window with files unlinked[1], but it is not much better.

In fact the rsync was a misleading placeholder.  What I really meant
to convey is that this is not something "git checkout" and "git reset
--hard" are designed to do, and that when this much control is needed,
it can be easier to update files out-of-band.

> If you truly want an atomicity, you can make /etc/interesting-subdir a
> symbolic link that points to either interesting-subdir-{0,1}, do the above
> procedure of yours against interesting-subdir-0 (or 1) that is currently
> not pointed by the symbolic link, and when everything in that one is Ok,
> atomically switch the symbolic link to point at it.

True.  Though in practice, a little race might be considered ok. :)

Thanks for clarifying.
Jonathan

[1] rsync with --files-from can update files in a specific order,
which might be appropriate in some cases.