bisect--helper: `bisect_write` shell function in C

Reimplement the `bisect_write` shell function in C and add a
`bisect-write` subcommand to `git bisect--helper` to call it from
git-bisect.sh

Using `--bisect-write` subcommand is a temporary measure to port shell
function in 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 some other methods.

Note: bisect_write() uses two variables namely TERM_GOOD and TERM_BAD
from the global shell script thus we need to pass it to the subcommand
using the arguments. We then store them in a struct bisect_terms and
pass the memory address around functions.

Add a log_commit() helper function to write the contents of the commit message
header to a file which will be re-used in future parts of the code as
well.

Also introduce a function free_terms() to free the memory of `struct
bisect_terms` and set_terms() to set the values of members in `struct
bisect_terms`.

Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index aa6495dc8413eb54294b593896a9a9bd7e64d8fa..df821be4b2b67f6dc33ab3b2d9f586687faf6311 100644 (file)
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -12,15 +12,37 @@ 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_start, "BISECT_START")
 static GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
+static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
 
 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"),
        N_("git bisect--helper --bisect-reset [<commit>]"),
+       N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
        NULL
 };
 
+struct bisect_terms {
+       char *term_good;
+       char *term_bad;
+};
+
+static void free_terms(struct bisect_terms *terms)
+{
+       FREE_AND_NULL(terms->term_good);
+       FREE_AND_NULL(terms->term_bad);
+}
+
+static void set_terms(struct bisect_terms *terms, const char *bad,
+                     const char *good)
+{
+       free((void *)terms->term_good);
+       terms->term_good = xstrdup(good);
+       free((void *)terms->term_bad);
+       terms->term_bad = xstrdup(bad);
+}
+
 /*
  * Check whether the string `term` belongs to the set of strings
  * included in the variable arguments.
@@ -148,6 +170,70 @@ static int bisect_reset(const char *commit)
        return bisect_clean_state();
 }
 
+static void log_commit(FILE *fp, char *fmt, const char *state,
+                      struct commit *commit)
+{
+       struct pretty_print_context pp = {0};
+       struct strbuf commit_msg = STRBUF_INIT;
+       char *label = xstrfmt(fmt, state);
+
+       format_commit_message(commit, "%s", &commit_msg, &pp);
+
+       fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
+               commit_msg.buf);
+
+       strbuf_release(&commit_msg);
+       free(label);
+}
+
+static int bisect_write(const char *state, const char *rev,
+                       const struct bisect_terms *terms, int nolog)
+{
+       struct strbuf tag = STRBUF_INIT;
+       struct object_id oid;
+       struct commit *commit;
+       FILE *fp = NULL;
+       int retval = 0;
+
+       if (!strcmp(state, terms->term_bad)) {
+               strbuf_addf(&tag, "refs/bisect/%s", state);
+       } else if (one_of(state, terms->term_good, "skip", NULL)) {
+               strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
+       } else {
+               retval = error(_("Bad bisect_write argument: %s"), state);
+               goto finish;
+       }
+
+       if (get_oid(rev, &oid)) {
+               retval = error(_("couldn't get the oid of the rev '%s'"), rev);
+               goto finish;
+       }
+
+       if (update_ref(NULL, tag.buf, &oid, NULL, 0,
+                      UPDATE_REFS_MSG_ON_ERR)) {
+               retval = -1;
+               goto finish;
+       }
+
+       fp = fopen(git_path_bisect_log(), "a");
+       if (!fp) {
+               retval = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
+               goto finish;
+       }
+
+       commit = lookup_commit_reference(the_repository, &oid);
+       log_commit(fp, "%s", state, commit);
+
+       if (!nolog)
+               fprintf(fp, "git bisect %s %s\n", state, rev);
+
+finish:
+       if (fp)
+               fclose(fp);
+       strbuf_release(&tag);
+       return retval;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
        enum {
@@ -155,9 +241,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
                WRITE_TERMS,
                BISECT_CLEAN_STATE,
                CHECK_EXPECTED_REVS,
-               BISECT_RESET
+               BISECT_RESET,
+               BISECT_WRITE
        } cmdmode = 0;
-       int no_checkout = 0;
+       int no_checkout = 0, res = 0, nolog = 0;
        struct option options[] = {
                OPT_CMDMODE(0, "next-all", &cmdmode,
                         N_("perform 'git bisect next'"), NEXT_ALL),
@@ -169,10 +256,15 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
                         N_("check for expected revs"), CHECK_EXPECTED_REVS),
                OPT_CMDMODE(0, "bisect-reset", &cmdmode,
                         N_("reset the bisection state"), BISECT_RESET),
+               OPT_CMDMODE(0, "bisect-write", &cmdmode,
+                        N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
                OPT_BOOL(0, "no-checkout", &no_checkout,
                         N_("update BISECT_HEAD instead of checking out the current commit")),
+               OPT_BOOL(0, "no-log", &nolog,
+                        N_("no log for BISECT_WRITE ")),
                OPT_END()
        };
+       struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 
        argc = parse_options(argc, argv, prefix, options,
                             git_bisect_helper_usage, 0);
@@ -198,8 +290,15 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
                if (argc > 1)
                        return error(_("--bisect-reset requires either no argument or a commit"));
                return !!bisect_reset(argc ? argv[0] : NULL);
+       case BISECT_WRITE:
+               if (argc != 4 && argc != 5)
+                       return error(_("--bisect-write requires either 4 or 5 arguments"));
+               set_terms(&terms, argv[3], argv[2]);
+               res = bisect_write(argv[0], argv[1], &terms, nolog);
+               break;
        default:
                return error("BUG: unknown subcommand '%d'", cmdmode);
        }
-       return 0;
+       free_terms(&terms);
+       return !!res;
 }

diff --git a/git-bisect.sh b/git-bisect.sh
index afbfbc1f8e33864b2f8c6aa7bda3e1cb98579cff..ebf445223ceb39175260663648f410fef8ca58f2 100755 (executable)
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -144,7 +144,7 @@ bisect_start() {
                0) state=$TERM_BAD ; bad_seen=1 ;;
                *) state=$TERM_GOOD ;;
                esac
-               eval="$eval bisect_write '$state' '$rev' 'nolog' &&"
+               eval="$eval git bisect--helper --bisect-write '$state' '$rev' '$TERM_GOOD' '$TERM_BAD' 'nolog' &&"
        done
        #
        # Verify HEAD.
@@ -220,23 +220,6 @@ bisect_start() {
        trap '-' 0
 }
 
-bisect_write() {
-       state="$1"
-       rev="$2"
-       nolog="$3"
-       case "$state" in
-               "$TERM_BAD")
-                       tag="$state" ;;
-               "$TERM_GOOD"|skip)
-                       tag="$state"-"$rev" ;;
-               *)
-                       die "$(eval_gettext "Bad bisect_write argument: \$state")" ;;
-       esac
-       git update-ref "refs/bisect/$tag" "$rev" || exit
-       echo "# $state: $(git show-branch $rev)" >>"$GIT_DIR/BISECT_LOG"
-       test -n "$nolog" || echo "git bisect $state $rev" >>"$GIT_DIR/BISECT_LOG"
-}
-
 bisect_skip() {
        all=''
        for arg in "$@"
@@ -263,7 +246,7 @@ bisect_state() {
                bisected_head=$(bisect_head)
                rev=$(git rev-parse --verify "$bisected_head") ||
                        die "$(eval_gettext "Bad rev input: \$bisected_head")"
-               bisect_write "$state" "$rev"
+               git bisect--helper --bisect-write "$state" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit
                git bisect--helper --check-expected-revs "$rev" ;;
        2,"$TERM_BAD"|*,"$TERM_GOOD"|*,skip)
                shift
@@ -276,7 +259,7 @@ bisect_state() {
                done
                for rev in $hash_list
                do
-                       bisect_write "$state" "$rev"
+                       git bisect--helper --bisect-write "$state" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit
                done
                git bisect--helper --check-expected-revs $hash_list ;;
        *,"$TERM_BAD")
@@ -413,7 +396,7 @@ bisect_replay () {
                        cmd="bisect_start $rev"
                        eval "$cmd" ;;
                "$TERM_GOOD"|"$TERM_BAD"|skip)
-                       bisect_write "$command" "$rev" ;;
+                       git bisect--helper --bisect-write "$command" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit;;
                terms)
                        bisect_terms $rev ;;
                *)