Re: [PATCH v13 04/13] bisect--helper: `bisect_clean_state` shell function in C

> Reimplement `bisect_clean_state` shell function in C and add a
> `bisect-clean-state` subcommand to `git bisect--helper` to call it from
> git-bisect.sh .
>
> Using `--bisect-clean-state` subcommand is a measure to port shell
> function to C so as to use the existing test suite. As more functions
> are ported, this subcommand will be retired but its implementation  will
> be called by bisect_reset() and bisect_start().
>
> Mentored-by: Lars Schneider <larsxschneider@gmail.com>
> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
> ---
>  bisect.c                 | 43 +++++++++++++++++++++++++++++++++++++++++++
>  bisect.h                 |  2 ++
>  builtin/bisect--helper.c | 14 +++++++++++++-
>  git-bisect.sh            | 26 +++-----------------------
>  4 files changed, 61 insertions(+), 24 deletions(-)
>
> diff --git a/bisect.c b/bisect.c
> index 6f512c2..45d598d 100644
> --- a/bisect.c
> +++ b/bisect.c
> @@ -430,6 +430,12 @@ static int read_bisect_refs(void)
>
>  static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
>  static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
> +static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
> +static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
> +static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
> +static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
> +static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
> +static GIT_PATH_FUNC(git_path_head_name, "head-name")
>
>  static void read_bisect_paths(struct argv_array *array)
>  {
> @@ -1040,3 +1046,40 @@ int estimate_bisect_steps(int all)
>
>         return (e < 3 * x) ? n : n - 1;
>  }
> +
> +static int mark_for_removal(const char *refname, const struct object_id *oid,
> +                           int flag, void *cb_data)
> +{
> +       struct string_list *refs = cb_data;
> +       char *ref = xstrfmt("refs/bisect%s", refname);
> +       string_list_append(refs, ref);
> +       return 0;
> +}
> +
> +int bisect_clean_state(void)
> +{
> +       int result = 0;
> +
> +       /* There may be some refs packed during bisection */
> +       struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
> +       for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
> +       string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
> +       result = delete_refs(&refs_for_removal, REF_NODEREF);
> +       refs_for_removal.strdup_strings = 1;
> +       string_list_clear(&refs_for_removal, 0);
> +       unlink_or_warn(git_path_bisect_expected_rev());
> +       unlink_or_warn(git_path_bisect_ancestors_ok());
> +       unlink_or_warn(git_path_bisect_log());
> +       unlink_or_warn(git_path_bisect_names());
> +       unlink_or_warn(git_path_bisect_run());
> +       unlink_or_warn(git_path_bisect_terms());
> +       /* Cleanup head-name if it got left by an old version of git-bisect */
> +       unlink_or_warn(git_path_head_name());
> +       /*
> +        * Cleanup BISECT_START last to support the --no-checkout option
> +        * introduced in the commit 4796e823a.
> +        */
> +       unlink_or_warn(git_path_bisect_start());
> +
> +       return result;
> +}
> diff --git a/bisect.h b/bisect.h
> index acd12ef..0ae63d4 100644
> --- a/bisect.h
> +++ b/bisect.h
> @@ -28,4 +28,6 @@ extern int estimate_bisect_steps(int all);
>
>  extern void read_bisect_terms(const char **bad, const char **good);
>
> +extern int bisect_clean_state(void);
> +
>  #endif
> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
> index 30e1031..e50934c 100644
> --- a/builtin/bisect--helper.c
> +++ b/builtin/bisect--helper.c
> @@ -5,10 +5,15 @@
>  #include "refs.h"
>
>  static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
> +static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
> +static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
> +static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
> +static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
>
>  static const char * const git_bisect_helper_usage[] = {
>         N_("git bisect--helper --next-all [--no-checkout]"),
>         N_("git bisect--helper --write-terms <bad_term> <good_term>"),
> +       N_("git bisect--helper --bisect-clean-state"),
>         NULL
>  };
>
> @@ -83,7 +88,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
>  {
>         enum {
>                 NEXT_ALL = 1,
> -               WRITE_TERMS
> +               WRITE_TERMS,
> +               BISECT_CLEAN_STATE
>         } cmdmode = 0;
>         int no_checkout = 0;
>         struct option options[] = {
> @@ -91,6 +97,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
>                          N_("perform 'git bisect next'"), NEXT_ALL),
>                 OPT_CMDMODE(0, "write-terms", &cmdmode,
>                          N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
> +               OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
> +                        N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
>                 OPT_BOOL(0, "no-checkout", &no_checkout,
>                          N_("update BISECT_HEAD instead of checking out the current commit")),
>                 OPT_END()
> @@ -109,6 +117,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
>                 if (argc != 2)
>                         die(_("--write-terms requires two arguments"));
>                 return write_terms(argv[0], argv[1]);
> +       case BISECT_CLEAN_STATE:
> +               if (argc != 0)
> +                       die(_("--bisect-clean-state requires no arguments"));
> +               return bisect_clean_state();
>         default:
>                 die("BUG: unknown subcommand '%d'", cmdmode);
>         }
> diff --git a/git-bisect.sh b/git-bisect.sh
> index 9ef6cb8..f1202df 100755
> --- a/git-bisect.sh
> +++ b/git-bisect.sh
> @@ -186,7 +186,7 @@ bisect_start() {
>         #
>         # Get rid of any old bisect state.
>         #
> -       bisect_clean_state || exit
> +       git bisect--helper --bisect-clean-state || exit
>
>         #
>         # Change state.
> @@ -195,7 +195,7 @@ bisect_start() {
>         # We have to trap this to be able to clean up using
>         # "bisect_clean_state".
>         #
> -       trap 'bisect_clean_state' 0
> +       trap 'git bisect--helper --bisect-clean-state' 0
>         trap 'exit 255' 1 2 3 15
>
>         #
> @@ -430,27 +430,7 @@ bisect_reset() {
>                 die "$(eval_gettext "Could not check out original HEAD '\$branch'.
>  Try 'git bisect reset <commit>'.")"
>         fi
> -       bisect_clean_state
> -}
> -
> -bisect_clean_state() {
> -       # There may be some refs packed during bisection.
> -       git for-each-ref --format='%(refname) %(objectname)' refs/bisect/\* |
> -       while read ref hash
> -       do
> -               git update-ref -d $ref $hash || exit
> -       done
> -       rm -f "$GIT_DIR/BISECT_EXPECTED_REV" &&
> -       rm -f "$GIT_DIR/BISECT_ANCESTORS_OK" &&
> -       rm -f "$GIT_DIR/BISECT_LOG" &&
> -       rm -f "$GIT_DIR/BISECT_NAMES" &&
> -       rm -f "$GIT_DIR/BISECT_RUN" &&
> -       rm -f "$GIT_DIR/BISECT_TERMS" &&
> -       # Cleanup head-name if it got left by an old version of git-bisect
> -       rm -f "$GIT_DIR/head-name" &&
> -       git update-ref -d --no-deref BISECT_HEAD &&
> -       # clean up BISECT_START last
> -       rm -f "$GIT_DIR/BISECT_START"
> +       git bisect--helper --bisect-clean-state || exit
>  }
>
>  bisect_replay () {