Re: t5800-*.sh: Intermittent test failures

From: Jeff King <peff@peff.net>
Date: Sep 8, 2011, 18:20 UTC
Message-ID: <20110908182055.GA16500@sigill.intra.peff.net>
In-Reply-To: <4E68FE73.4000005@ramsay1.demon.co.uk>

On Thu, Sep 08, 2011 at 06:42:11PM +0100, Ramsay Jones wrote:

> When I run the tests with "make test >test-out", I see a failure rate of about
> 1 in 10. If I then set the debug environment variables (GIT_TRANSPORT_HELPER_DEBUG,
> GIT_TRANSLOOP_DEBUG and GIT_DEBUG_TESTGIT) and run the test script directly (-v),
> then the failure rate goes up to about 1 in 3.

Hmm. I can't reproduce a failure here, but I do get some weirdness. My recipe is:

-- >8 -- cat >foo.sh <<\EOF #!/bin/sh

exec >$1.out 2>&1

n=0
while test $n -lt 100; do
	n=$(($n+1))
	GIT_TRANSPORT_HELPER_DEBUG=1 \
	GIT_TRANSLOOP_DEBUG=1 \
	GIT_DEBUG_TESTGIT=1 \
	./t5800-remote-helpers.sh --root=/run/shm/git-tests-$1 -v || {
		echo FAIL $n
		exit 1
	}
	echo OK $n
done
EOF

# try to keep an 8-core machine busy
for i in `seq 1 16`; do
  sh foo.sh $i &
done
-- 8< --

I never see a test failure, but a few of the 16 end up hanging. The process tree for the hanged tests look like:

  t5800-remote-helper
    git push
      git-remote-testgit
        git fast-import
          git-fast-import

All of them are blocked on wait(), except for the final fast-import, which is blocked trying to read() from stdin.

-Peff