Re: v2.15.0-rc1 test failure

From: Adam Dinwoodie <adam@dinwoodie.org>
Date: Oct 12, 2017, 09:06 UTC
Message-ID: <20171012090648.GB6079@dinwoodie.org>
In-Reply-To: <338656d4-182b-563f-9195-515d213d4b6d@ramsayjones.plus.com>

On Thu, Oct 12, 2017 at 01:27:57AM +0100, Ramsay Jones wrote:

Show 30 quoted lines

> On 11/10/17 23:34, Adam Dinwoodie wrote:
> [snip]
> > Hi Ramsay,
> > 
> > I assume, given you're emailing me, that this is a Cygwin failure?
> 
> Yes, sorry, I should have made that clear.
> 
> > t0021.15 has PERL as a requirement, and I see semi-regular failures from
> > Git tests that are Perl-based in one way or another (git-svn tests are
> > the most common problems).  I've not spotted t0021 failing in that way,
> > but it sounds like the same class of problem.
> 
> Yep, many moons ago, I used to run the svn tests (on Linux and cygwin)
> which would fail intermittently on cygwin. I didn't notice any problem
> with perl though.
> 
> > I dig into these failures when I see them, mostly by running the script
> > a few hundred times until I get the failure again, and they've always
> > been Perl itself segfaulting.  That points to the problem being in
> > Cygwin's Perl package rather than Git, and it's very unlikely to be
> > anything that's got worse in v2.15.0.
> 
> Since I stopped running the svn tests, the number of intermittent test failures on cygwin have dropped significantly, but haven't gone away
> completely.
> 
> I just finished the second test-suite run and, of course, t0021 ran
> without problem this time. Hmm, I don't think I have time to chase
> this down at the moment. I will keep your 'perl hypothesis' in mind
> for next time, however.

Evidence for my Perl hypothesis, which I offer at least as much so other people can check my logic as anything else:

Here's a fairly typical set of verbose output from a test failing in this way [0]. The critical bit is the line "error: git-svn died of signal 11". Since git-svn is a Perl script, and Perl is the sort of interpreted language that would throw its own errors if it encountered a script bug, the fact that it's hitting a segfault means there's a problem of some ilk with the Perl interpreter itself.

[0]: https://github.com/me-and/Cygwin-Git/issues/13#issuecomment-211372448

Adam