Re: symbolic link management in git-archive

From: Sergio Callegari <sergio.callegari@gmail.com>
Date: Mar 27, 2008, 18:34 UTC
Message-ID: <loom.20080327T175844-199@post.gmane.org>
In-Reply-To: <7v3aqcb02s.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster <at> pobox.com> writes:

Show 13 quoted lines

> 
> Sergio Callegari <sergio.callegari <at> gmail.com> writes:
> 
> > I guess the answer is "no" or "not yet", but is there a way to tell the
> > zip
> > backend of git-archive to follow symbolic links rather than to store 
> > them?
> 
> I am not sure what you mean.  Are you tracking a symbolic link X that
> points at Y in your revision and expecting git-archive to include 
> whatever
> happens to be at Y (which may or may not even exist) when you run the
> command?

Yes, this is the case.

> If that is the case, the answer is "no" and "will never happen".  If you
> are tracking a symbolic link X that points at Y, the information git
> tracks is the fact that there is a symbolic link X that points at Y,

... I obviously agree with this!

> and
> not what Y happens to look like at a random moment.

Well, certainly if the zip backend of git-archive in addition to the -1 ... -9 switches also supported a --dereference switch, I would not run git-archive --format=zip --dereference at "random moments". I would run it when I am sure that things pointed at by the symbolic links in the tracked project actually point at sensible things.

> Change to Y is not
> tracked by git

Unless Y is also in the tracked project...

> so why should you get different output from git-archive of
> the same revision before and after you modify Y which is not part of the
> revision to begin with?

Basically, because if I make a zip archive instead of a git bundle, I want to store (and probably give to someone else) a copy of what _I see_ at a certain instant in time which might not exactly coincide with the tracked state.

Note that if Y is outside of the tracked project and I make an archive, and then I give the archive to my friend X, Mr. X will see the same symbolic link, but still a completely and randomly different content than I do, depending on where he is unpacking the archive.

But to get to a more practical case, my situation is this:

I have a project where I need to have the same content in multiple places, otherwise development tools are not happy. Since I do most of the development on Linux, I use symbolic links. This is very good, not just because I save space, but particularly because I am sure that the content cannot loose coherency (which would be very bad) at the different places.

Every now and then, to distribute snapshots of the project, I run git archive to make a zip file, that I give to other people. Unfortunately, some of them use Windows, where the symbolic links appear as one-liner text files. And obviously they cannot compile anything and they complain.

So I would like git archive to be able to make zip archives with the symbolic links /resolved/.

what I am asking is not to modify the standard behaviour of git archive to follow links, rather to have a switch to activate the dereferencing behaviour only when needed. In the end git archive is a nice shorthand for a checkout and a successive run of zip or tar and both zip and tar have a switch to control this dereferencing behaviour (BTW, zip on my distro dereferences by default, the switch is to store symbolic links).

Sergio