Re: Intermittent Failures in t1450-fsck (Bisected)

From: Brian Gernhardt <benji@silverinsanity.com>
Date: May 5, 2011, 20:04 UTC
Message-ID: <60194977-A4A9-4E18-9878-C1CDE77B75C2@silverinsanity.com>
In-Reply-To: <20110505093226.GA29595@sigill.intra.peff.net>

On May 5, 2011, at 5:32 AM, Jeff King wrote:

Show 35 quoted lines

> On Thu, May 05, 2011 at 02:46:52AM -0400, Brian Gernhardt wrote:
>>> t1450-fsck fails in test 10 "tag pointing to something else than its type", but only if I run it as part of the full test suite (with either `make test` or `make prove`).  If I run the test separately, it passes.
>>> 
>>> The output from running with GIT_TEST_OPTS="-v" is:
>>> 
>>> expecting success: 
>>> 	sha=$(echo blob | git hash-object -w --stdin) &&
>>> 	test_when_finished "remove_object $sha" &&
>>> 	cat >wrong-tag <<-EOF &&
>>> 	object $sha
>>> 	type commit
>>> 	tag wrong
>>> 	tagger T A Gger <tagger@example.com> 1234567890 -0000
>>> 
>>> 	This is an invalid tag.
>>> 	EOF
>>> 
>>> 	tag=$(git hash-object -t tag -w --stdin <wrong-tag) &&
>>> 	test_when_finished "remove_object $tag" &&
>>> 	echo $tag >.git/refs/tags/wrong &&
>>> 	test_when_finished "git update-ref -d refs/tags/wrong" &&
>>> 	test_must_fail git fsck --tags 2>out &&
>>> 	cat out &&
>>> 	grep "error in tag.*broken links" out
>>> 
>>> tagged commit 63499e4ea8e096b831515ceb1d5a7593e4d87ae5 (wrong) in 66f6581d549f70e05ca586bc2df5c15a95662c36
>>> missing commit 63499e4ea8e096b831515ceb1d5a7593e4d87ae5
>>> error: Object 63499e4ea8e096b831515ceb1d5a7593e4d87ae5 is a commit, not a blob
>>> error: 63499e4ea8e096b831515ceb1d5a7593e4d87ae5: object corrupt or missing
>>> not ok - 10 tag pointing to something else than its type
> 
> So how did you bisect down to it? You said reverting e96c19c fixes it,
> which does seem like strong evidence, but what I am wondering is if a
> _different_ test in t1450 fails at e96c19c. That would point to
> something else funny going on.

I actually bisected the test failure to "c5a5f12e: Merge branch 'ef/maint-strbuf-init'", and then rebased e96c19c on top of 2a2dbd2 to see what actually caused the error.  I re-ran it like this again today and got the exact same error.

> Double weird is that my output for t1450.10 is totally different from
> that.  Which commit are you testing on?

The original e-mail was from next at that point.  The output from the rebased version and current next (76e37e2) is identical.

> Given that the problem seems racy and intermittent, have you tried
> running under valgrind?

This is on my OS X laptop and last I knew valgrind was very buggy on OS X, so I've never tried it.  I'll install it now and see if I can get anything useful out of it.

~~ Brian