Re: [Outreachy] [PATCH v2] bisect--helper: avoid free-after-use

>
> Junio C Hamano <gitster@pobox.com> writes:
>
> > Subject: Re: [Outreachy] [PATCH v2] bisect--helper: avoid free-after-use
>
> It is surprising with multiple mentors, nobody noticed free-after-use
> is perfectly fine---it is use-after-free we would want to avoid.
>

> > Miriam Rubio <mirucam@gmail.com> writes:
> >
> >> From: Tanushree Tumane <tanushreetumane@gmail.com>
> >>
> >> In 5e82c3dd22a (bisect--helper: `bisect_reset` shell function in C,
> >> 2019-01-02), the `git bisect reset` subcommand was ported to C. When the
> >> call to `git checkout` failed, an error message was reported to the
> >> user.
> >>
> >> However, this error message used the `strbuf` that had just been
> >> released already. Let's switch that around: first use it, then release
> >> it.
> >>
> >> Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
> >> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> >> Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
> >> Signed-off-by: Miriam Rubio <mirucam@gmail.com>
> >> ---
> >> This patch is a new version of
> >> https://public-inbox.org/git/20191208172813.16518-1-mirucam@gmail.com/
> >> which itself has been sent previously by Tanushree
> >> (https://public-inbox.org/git/64117cde718f0d56ebfa4c30f4d8fe2155f5cf65.1551003074.git.gitgitgadget@gmail.com/).
> >>
> >>  builtin/bisect--helper.c | 7 ++++---
> >>  1 file changed, 4 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
> >> index 1fbe156e67..3055b2bb50 100644
> >> --- a/builtin/bisect--helper.c
> >> +++ b/builtin/bisect--helper.c
> >> @@ -169,11 +169,12 @@ static int bisect_reset(const char *commit)
> >>
> >>              argv_array_pushl(&argv, "checkout", branch.buf, "--", NULL);
> >>              if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
> >> +                    error(_("could not check out original"
> >> +                            " HEAD '%s'. Try 'git bisect"
> >> +                            " reset <commit>'."), branch.buf);
> >>                      strbuf_release(&branch);
> >>                      argv_array_clear(&argv);
> >> -                    return error(_("could not check out original"
> >> -                                   " HEAD '%s'. Try 'git bisect"
> >> -                                   " reset <commit>'."), branch.buf);
> >
> > The original obviously was bad X-<.  Will queue.  Thanks.
> >
> >> +                    return -1;
> >>              }
> >>              argv_array_clear(&argv);
> >>      }