Re: [PATCH 0/3] leak tests: mark remaining tests leak-free as such

From: Jeff King <peff@peff.net>
Date: Aug 24, 2023, 20:50 UTC
Message-ID: <20230824205009.GA1516@coredump.intra.peff.net>
In-Reply-To: <cover.1692902414.git.me@ttaylorr.com>

On Thu, Aug 24, 2023 at 02:40:34PM -0400, Taylor Blau wrote:

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> While working on another topic that cleared up some leaks, I wanted to
> see if any new tests became leak-free, so I ran:
> 
>     $ make SANITIZE=leak
>     $ make GIT_TEST_PASSING_SANITIZE_LEAK=check GIT_TEST_OPTS=-i test

Is that exactly what you ran? Because I'd expect the second "make" invocation to rebuild Git _without_ SANITIZE=leak enabled in that case. (Though I would have then expected most of the scripts to complain loudly about the mismatch; did you "cd t" in between the two?).

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>  t/t3321-notes-stripspace.sh | 1 +
>  t/t5571-pre-push-hook.sh    | 1 +
>  t/t5583-push-branches.sh    | 1 +
>  t/t7516-commit-races.sh     | 2 ++
>  4 files changed, 5 insertions(+)

If I run a single:

  make SANITIZE=leak GIT_TEST_PASSING_SANITIZE_LEAK=check GIT_TEST_OPTS=-i test

on v2.42.0, I get many hits. All of the ones you mentioned, plus:

  t7408 t5407 t7008 t5811 t3407 t6001 t4058 t2016

If I run a few by hand, I _do_ see leaks in them, but the exit codes are hidden from the test suite (they are sub-programs of scripts, etc). I guess you also have:

  GIT_TEST_SANITIZE_LEAK_LOG=true

set, which should find those (and which you mention in your first commit). Turning that on eliminates some of them, but I'm left with:

  t5614 t5317 t5503

not in your list. Which is super weird, because t5614 is marked with TEST_PASSES_SANITIZE_LEAK. Hrm. And if I run it again, I get a _different_ set (t5614 again, along with your 4, but also t5303, t7701, and t4050). I wonder if we have a race in the leak-log code or something (I'm running under prove with -j32, naturally).

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> This series marks all leak-free tests as such, meaning that the above
> "make test" invocation will pass after this series. The bulk of the
> tests which are marked here in the first patch were always
> leak-free[^1]. The remaining two patches address a couple of special
> cases of tests which are also leak-free.

Hmm. If I check t5571, for example, by bisecting on:

  make SANITIZE=leak && (cd t && ./t5571-pre-push-hook.sh -v -i)

it shows that it was fixed by 861c56f6f9 (branch: fix a leak in setup_tracking, 2023-06-11), which make sense. There are a bunch of leak fixes in the same series, which makes me wonder if they're responsible for most of these.

If the leaks are gone, I am happy that we are marking them. But it is weird to me that we are getting different results.

-Peff