From: Jeff King <peff@peff.net>
Date: Thu, 23 Jun 2016 19:22:51 GMT
Subject: Re: [PATCH 2/2] archive-tar: write extended headers for far-future mtime
Message-ID: <20160623192251.GB32745@sigill.intra.peff.net>
In-Reply-To: <576A2631.2000608@web.de>

On Wed, Jun 22, 2016 at 07:46:25AM +0200, René Scharfe wrote:

> Am 21.06.2016 um 00:54 schrieb René Scharfe:
> > Am 16.06.2016 um 06:37 schrieb Jeff King:
> > >    2. System tars that cannot handle pax headers.
> > 
> > In t5000 there is a simple interpreter for path headers for systems
> > whose tar doesn't handle them.  Adding one for mtime headers may be
> > feasible.
> > 
> > It's just a bit complicated to link a pax header file to the file it
> > applies to when it doesn't also contain a path header.  But we know that
> > the mtime of all entries in tar files created by git archive are is the
> > same, so we could simply read one header and then adjust the mtime of
> > all files accordingly.
> 
> This brings me to the idea of using a single global pax header for mtime
> instead of one per entry.  It reduces the size of the archive and allows for
> slightly easier testing -- it just fits better since we know that all our
> mtimes are the same.

Yeah, I had a similar thought while writing it, but wasn't quite sure
how that was supposed to be formatted. I modeled my output after what
GNU tar writes, but of course they are expecting a different mtime for
each file.

I'll look into how global pax headers should look.

-Peff