(unknown)

From: Hin-Tak Leung <htl10@users.sourceforge.net>
Date: Aug 4, 2011, 17:27 UTC
Message-ID: <1312478843.69439.YahooMailClassic@web29510.mail.ird.yahoo.com>

--- On Thu, 4/8/11, Jeff King <peff@peff.net> wrote:

Show 16 quoted lines

> On Wed, Aug 03, 2011 at 11:17:59PM
> +0100, Hin-Tak Leung wrote:
> 
> > The summary of the problem is that, git-archive's
> "--format=tar"
> > option really write the pax format most of the time,
> and some
> > cross-platform archive extraction library (rather than
> the
> > all-powerful GNU tar) really does not think that's the
> tar format and
> > bail out.
> 
> Out of curiosity, what is the library? Putting pax headers
> into ustar
> format has been standardized in POSIX since 2001.

The R people wrote their own in the R language (and the person who responded to my post in that R-devel thread was possibly the one who wrote that part, I believe) - The main reason is probably cross-platform-ness and independence from other programming languages - they are gradually moving away from invoking system() (because they need to run on windows and they used to require many cygwin/mingw tools to build add-on packages).

The R code which does that, scan for certain patterns after seek() into the gunzip'ed stream after 512(?) bytes. It is in a file R/src/library/utils/R/tar.R under the source repository.

Show 18 quoted lines

> That header contains useful information (the commit id from
> which the
> archive was generated). And there is a way to turn it off:
> give a tree
> id instead of a commit id. There is an example in the
> git-archive
> manpage that does exactly this already. Look for the
> example mentioning
> "pax header" here:
> 
>   http://www.kernel.org/pub/software/scm/git/docs/git-archive.html
> 
> It might be a bit more obvious to find if we actually had
> a
> --no-pax-header option, though.
> 
> -Peff
>

I think I tried the tree example and the R code also didn't like it much... may be I'll give it another try.