Re: [PATCH v4 2/5] t5000: test tar files that overflow ustar headers

From: Jeff King <peff@peff.net>
Date: Jul 14, 2016, 18:21 UTC
Message-ID: <20160714182108.GB16497@sigill.intra.peff.net>
In-Reply-To: <alpine.DEB.2.20.1607141745420.6426@virtualbox>

On Thu, Jul 14, 2016 at 05:47:41PM +0200, Johannes Schindelin wrote:

Show 17 quoted lines

> On Thu, 30 Jun 2016, Jeff King wrote:
> 
> > The ustar format only has room for 11 (or 12, depending on
> > some implementations) octal digits for the size and mtime of
> > each file. For values larger than this, we have to add pax
> > extended headers to specify the real data, and git does not
> > yet know how to do so.
> >
> > [...]
> >  t/t5000/19f9c8273ec45a8938e6999cb59b3ff66739902a | Bin 0 -> 2048 bytes
> 
> It appears that this blob cannot be read when sizeof(unsigned long) == 4.
> This happens to break the t5000 test on Windows, where that comparison
> holds true.
> 
> I am sure that I missed some other discussion about this issue... could
> you point me to it?

There's tons of discussion in:

  http://thread.gmane.org/gmane.comp.version-control.git/297409

but frankly it is not worth your time to read it. These tests are about overflowing the tar limits, which can only happen with times and sizes greater than 32-bits. The right thing to do is to skip the tests entirely on systems where sizeof(unsigned long) is less than 8 (the actual value is 64GB+1, so technically a 37-bit system would work, but I think it is OK for the test-skipping to be less specific).

-Peff