Re: git and mtime

From: Joey Hess <joey@kitenet.net>
Date: Nov 20, 2008, 19:24 UTC
Message-ID: <20081120192400.GB25604@kodama.kitenet.net>
In-Reply-To: <alpine.LNX.1.00.0811201223300.19665@iabervon.org>

On Thu, 20 Nov 2008, Roger Leigh wrote:

> Except in this case I'm storing the content of *tarballs* (along with
> pristine-tar).  I'm committing exactly what's in the tarball with
> no changes (this is a requirement).  I can't change the source prior
> to commit.

Note that pristine-tar will work no matter what the mtimes or other file metadata are, none of that affects generation of deltas or regeneration of tarballs from them.

Also, the source you commit does not really have to be identical to what's in the tarball. (Despite what it may say in the man page. ;-) A larger delta will be generated if something is different.

So, three possible approaches:

1. Run make or whatever you need to do before running pristine-tar,
   and put up with a larger delta.

2. Before building, you could use pristine-tar to extract the original
   tarball, and then have a program examine that tarball, and reset the
   mtimes in your build tree to match the mtimes of files in it.
   (Or you could duplicate the info with metastore -m, which could be
   restored quicker.)

3. Store uncompressed tarballs in git, so that they will pack
   efficiently, and use pristine-gz to regenerate the pristine .tar.gz.
   Only mentioned because this could be more space efficient than option
   #1, if the pristine-tar deltas get too large.

-- 
see shy jo