Re: [PATCH v4 5/6] bisect--helper: reimplement `bisect_run` shell function in C

["Miriam R." <mirucam@gmail.com>]

Hi Johannes,

El mar, 17 ago 2021 a las 13:42, Johannes Schindelin
(<Johannes.Schindelin@gmx.de>) escribió:
>
> Hi Miriam,
>
> On Tue, 17 Aug 2021, Miriam Rubio wrote:
>
> > From: Tanushree Tumane <tanushreetumane@gmail.com>
> >
> > Reimplement the `bisect_run()` shell function
> > in C and also add `--bisect-run` subcommand to
> > `git bisect--helper` to call it from git-bisect.sh.
> >
> > Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> > Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
> > Signed-off-by: Miriam Rubio <mirucam@gmail.com>
> > ---
> >  builtin/bisect--helper.c | 75 ++++++++++++++++++++++++++++++++++++++++
> >  git-bisect.sh            | 62 +--------------------------------
> >  2 files changed, 76 insertions(+), 61 deletions(-)
> >
> > diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
> > index 4258429c1c..852e0a30fb 100644
> > --- a/builtin/bisect--helper.c
> > +++ b/builtin/bisect--helper.c
> > @@ -31,6 +31,7 @@ static const char * const git_bisect_helper_usage[] = {
> >       N_("git bisect--helper --bisect-replay <filename>"),
> >       N_("git bisect--helper --bisect-skip [(<rev>|<range>)...]"),
> >       N_("git bisect--helper --bisect-visualize"),
> > +     N_("git bisect--helper --bisect-run <cmd>..."),
> >       NULL
> >  };
> >
> > @@ -1075,6 +1076,71 @@ static int bisect_visualize(struct bisect_terms *terms, const char **argv, int a
> >       return res;
> >  }
> >
> > +static int bisect_run(struct bisect_terms *terms, const char **argv, int argc)
> > +{
> > +     int res = BISECT_OK;
> > +     struct strbuf command = STRBUF_INIT;
> > +     struct strvec args = STRVEC_INIT;
> > +     struct strvec run_args = STRVEC_INIT;
> > +     int exit = 0;
> > +
> > +     if (bisect_next_check(terms, NULL))
> > +             return BISECT_FAILED;
> > +
> > +     if (argc)
> > +             sq_quote_argv(&command, argv);
> > +     else
> > +             return BISECT_FAILED;
>
> Do we want to say something helpful here, e.g. _("bisect run failed: no
> command provided.")?
>
Ok, noted
> > +
> > +     strvec_push(&run_args, command.buf);
> > +
> > +     while (1) {
> > +             strvec_clear(&args);
> > +             exit = 1;
> > +
> > +             printf(_("running %s"), command.buf);
> > +             res = run_command_v_opt(run_args.v, RUN_USING_SHELL);
> > +
> > +             if (res < 0 || 128 <= res) {
> > +                     error(_("bisect run failed: exit code %d from"
> > +                             " '%s' is < 0 or >= 128"), res, command.buf);
> > +                     strbuf_release(&command);
> > +                     return res;
> > +             }
> > +
> > +             if (res == 125)
> > +                     strvec_push(&args, "skip");
> > +             else if (res > 0)
> > +                     strvec_push(&args, terms->term_bad);
> > +             else
> > +                     strvec_push(&args, terms->term_good);
> > +
> > +             res = bisect_state(terms, args.v, args.nr);
>
> Since `args.nr` will always be 1, it would probably be better to use
> something like this:
>
>                 const char *new_state;
>
>                 [...]
>                 if (res == 125)
>                         new_state = "skip";
>                 else
>                         new_state = res > 0 ?
>                                 terms->term_bad : terms->term_good;
>
>                 res = bisect_state(terms, &new_state, 1);
>
Yes, indeed. I will change it.
> Also: I think at this stage, an equivalent to `cat "$GIT_DIR/BISECT_RUN"`
> is missing.
In the previous patch series (v3), I implemented the equivalent to the
cat command but I understood
reviewers wanted to print the output to the user, so I reverted my
changes for this version.
https://lore.kernel.org/git/20210411095538.34129-4-mirucam@gmail.com/

>
> > +
> > +             if (res == BISECT_ONLY_SKIPPED_LEFT)
> > +                     error(_("bisect run cannot continue any more"));
> > +             else if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) {
> > +                     printf(_("bisect run success"));
> > +                     res = BISECT_OK;
> > +             } else if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
> > +                     printf(_("bisect found first bad commit"));
> > +                     res = BISECT_OK;
> > +             } else if (res) {
> > +                     error(_("bisect run failed:'git bisect--helper --bisect-state"
> > +                     " %s' exited with error code %d"), args.v[0], res);
> > +             } else {
> > +                     exit = 0;
>
> Since the only purpose of `exit` seems to be that the loop should continue
> if `exit` is set to 0, and it is only set here, how about doing away with
> the variable altogether and writing `continue;` instead of `exit = 0;`?
> Then the conditional block below does not need to be conditional.
>
Noted.
> Other than that: well done!
>
Thank you for reviewing!,
Miriam


> Ciao,
> Dscho
>
> > +             }
> > +
> > +             if (exit) {
> > +                     strbuf_release(&command);
> > +                     strvec_clear(&args);
> > +                     strvec_clear(&run_args);
> > +                     return res;
> > +             }
> > +     }
> > +}
> > +
> >  int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
> >  {
> >       enum {
> > @@ -1089,6 +1155,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
> >               BISECT_REPLAY,
> >               BISECT_SKIP,
> >               BISECT_VISUALIZE,
> > +             BISECT_RUN,
> >       } cmdmode = 0;
> >       int res = 0, nolog = 0;
> >       struct option options[] = {
> > @@ -1112,6 +1179,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
> >                        N_("skip some commits for checkout"), BISECT_SKIP),
> >               OPT_CMDMODE(0, "bisect-visualize", &cmdmode,
> >                        N_("visualize the bisection"), BISECT_VISUALIZE),
> > +             OPT_CMDMODE(0, "bisect-run", &cmdmode,
> > +                      N_("use <cmd>... to automatically bisect."), BISECT_RUN),
> >               OPT_BOOL(0, "no-log", &nolog,
> >                        N_("no log for BISECT_WRITE")),
> >               OPT_END()
> > @@ -1177,6 +1246,12 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
> >               get_terms(&terms);
> >               res = bisect_visualize(&terms, argv, argc);
> >               break;
> > +     case BISECT_RUN:
> > +             if (!argc)
> > +                     return error(_("bisect run failed: no command provided."));
> > +             get_terms(&terms);
> > +             res = bisect_run(&terms, argv, argc);
> > +             break;
> >       default:
> >               BUG("unknown subcommand %d", cmdmode);
> >       }
> > diff --git a/git-bisect.sh b/git-bisect.sh
> > index 95f7f3fb8c..e83d011e17 100755
> > --- a/git-bisect.sh
> > +++ b/git-bisect.sh
> > @@ -39,66 +39,6 @@ _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
> >  TERM_BAD=bad
> >  TERM_GOOD=good
> >
> > -bisect_run () {
> > -     git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
> > -
> > -     test -n "$*" || die "$(gettext "bisect run failed: no command provided.")"
> > -
> > -     while true
> > -     do
> > -             command="$@"
> > -             eval_gettextln "running \$command"
> > -             "$@"
> > -             res=$?
> > -
> > -             # Check for really bad run error.
> > -             if [ $res -lt 0 -o $res -ge 128 ]
> > -             then
> > -                     eval_gettextln "bisect run failed:
> > -exit code \$res from '\$command' is < 0 or >= 128" >&2
> > -                     exit $res
> > -             fi
> > -
> > -             # Find current state depending on run success or failure.
> > -             # A special exit code of 125 means cannot test.
> > -             if [ $res -eq 125 ]
> > -             then
> > -                     state='skip'
> > -             elif [ $res -gt 0 ]
> > -             then
> > -                     state="$TERM_BAD"
> > -             else
> > -                     state="$TERM_GOOD"
> > -             fi
> > -
> > -             git bisect--helper --bisect-state $state >"$GIT_DIR/BISECT_RUN"
> > -             res=$?
> > -
> > -             cat "$GIT_DIR/BISECT_RUN"
> > -
> > -             if sane_grep "first $TERM_BAD commit could be any of" "$GIT_DIR/BISECT_RUN" \
> > -                     >/dev/null
> > -             then
> > -                     gettextln "bisect run cannot continue any more" >&2
> > -                     exit $res
> > -             fi
> > -
> > -             if [ $res -ne 0 ]
> > -             then
> > -                     eval_gettextln "bisect run failed:
> > -'bisect-state \$state' exited with error code \$res" >&2
> > -                     exit $res
> > -             fi
> > -
> > -             if sane_grep "is the first $TERM_BAD commit" "$GIT_DIR/BISECT_RUN" >/dev/null
> > -             then
> > -                     gettextln "bisect run success"
> > -                     exit 0;
> > -             fi
> > -
> > -     done
> > -}
> > -
> >  get_terms () {
> >       if test -s "$GIT_DIR/BISECT_TERMS"
> >       then
> > @@ -137,7 +77,7 @@ case "$#" in
> >       log)
> >               git bisect--helper --bisect-log || exit ;;
> >       run)
> > -             bisect_run "$@" ;;
> > +             git bisect--helper --bisect-run "$@" || exit;;
> >       terms)
> >               git bisect--helper --bisect-terms "$@" || exit;;
> >       *)
> > --
> > 2.29.2
> >
> >