Re: [PATCH] wrap-for-bin.sh: facilitate running Git executables under valgrind

From: Antonio Ospite <ao2@ao2.it>
Date: May 9, 2018, 15:56 UTC
Message-ID: <20180509175647.0961d469e01367783090e764@ao2.it>
In-Reply-To: <CABPp-BEvNOBkq0-v_Uq0CHkvRixCKmUhYPMeH-MHHZGb0x9NkA@mail.gmail.com>

On Wed, 9 May 2018 08:25:21 -0700 Elijah Newren <newren@gmail.com> wrote:

> Hi Antonio,
>

Hi Elijah,

Show 39 quoted lines

> On Wed, May 9, 2018 at 6:28 AM, Antonio Ospite <ao2@ao2.it> wrote:
> > Testing locally built git executables under valgrind is not immediate.
> >
> > Something like the following does not work:
> >
> >   $ valgrind ./bin-wrappers/git
> >
> > because the wrapper script forks and execs the command and valgrind does
> > not track children processes by default.
> >
> > Something like the following may work:
> >
> >   $ valgrind --trace-children=yes ./bin-wrappers/git
> >
> > However it's counterintuitive and not ideal anyways because valgrind is
> > supposed to be called on the actual executable, not on wrapper scripts.
> >
> > So, following the idea from commit 6a94088cc ("test: facilitate
> > debugging Git executables in tests with gdb", 2015-10-30) provide
> > a mechanism in the wrapper script to call valgrind directly on the
> > actual executable.
> >
> > This mechanism could even be used by the test infrastructure in the
> > future, but it is already useful by its own on the command line:
> >
> >   $ GIT_TEST_VALGRIND=1 \
> >     GIT_VALGRIND_OPTIONS="--leak-check=full" \
> >     ./bin-wrappers/git
> >
> 
> Wow, timing; nice to see someone else finds this kind of thing useful.
> 
> I submitted something very similar recently; see commit 842436466aa5
> ("Make running git under other debugger-like programs easy",
> 2018-04-24) from next, or the discussion at
> https://public-inbox.org/git/20180424234645.8735-1-newren@gmail.com/.
> That other patch has the advantage of enabling the user to run git
> under other debugger-like programs besides just gdb and valgrind.
>

Thanks Elijah, I am not subscribed to the list so I didn't see your change and I usually only track the master branch.

Obviously your changes work for me, so I am dropping my patch.

As the changes in 842436466aa5 ("Make running git under other debugger-like programs easy", 2018-04-24) are not specific to valgrind they should also address Jeff's concerns in the sense that it's up to the particular GIT_DEBUGGER how it handles sub-processes.

In valgrind case one may still want to pass "--trace-children=yes" in GIT_DEBUGGER after all for better coverage. Thank you Jeff for the remark.

Ciao,
   Antonio

-- 
Antonio Ospite
https://ao2.it
https://twitter.com/ao2it

A: Because it messes up the order in which people normally read text.
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