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-rw-r--r--third_party/git/builtin/bisect--helper.c726
1 files changed, 726 insertions, 0 deletions
diff --git a/third_party/git/builtin/bisect--helper.c b/third_party/git/builtin/bisect--helper.c
new file mode 100644
index 000000000000..c1c40b516df7
--- /dev/null
+++ b/third_party/git/builtin/bisect--helper.c
@@ -0,0 +1,726 @@
+#include "builtin.h"
+#include "cache.h"
+#include "parse-options.h"
+#include "bisect.h"
+#include "refs.h"
+#include "dir.h"
+#include "argv-array.h"
+#include "run-command.h"
+#include "prompt.h"
+#include "quote.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_start, "BISECT_START")
+static GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
+static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
+static GIT_PATH_FUNC(git_path_head_name, "head-name")
+static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
+
+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>"),
+	N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
+	N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
+	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
+	N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
+					     "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
+	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);
+}
+
+static const char vocab_bad[] = "bad|new";
+static const char vocab_good[] = "good|old";
+
+/*
+ * Check whether the string `term` belongs to the set of strings
+ * included in the variable arguments.
+ */
+LAST_ARG_MUST_BE_NULL
+static int one_of(const char *term, ...)
+{
+	int res = 0;
+	va_list matches;
+	const char *match;
+
+	va_start(matches, term);
+	while (!res && (match = va_arg(matches, const char *)))
+		res = !strcmp(term, match);
+	va_end(matches);
+
+	return res;
+}
+
+static int check_term_format(const char *term, const char *orig_term)
+{
+	int res;
+	char *new_term = xstrfmt("refs/bisect/%s", term);
+
+	res = check_refname_format(new_term, 0);
+	free(new_term);
+
+	if (res)
+		return error(_("'%s' is not a valid term"), term);
+
+	if (one_of(term, "help", "start", "skip", "next", "reset",
+			"visualize", "view", "replay", "log", "run", "terms", NULL))
+		return error(_("can't use the builtin command '%s' as a term"), term);
+
+	/*
+	 * In theory, nothing prevents swapping completely good and bad,
+	 * but this situation could be confusing and hasn't been tested
+	 * enough. Forbid it for now.
+	 */
+
+	if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
+		 (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
+		return error(_("can't change the meaning of the term '%s'"), term);
+
+	return 0;
+}
+
+static int write_terms(const char *bad, const char *good)
+{
+	FILE *fp = NULL;
+	int res;
+
+	if (!strcmp(bad, good))
+		return error(_("please use two different terms"));
+
+	if (check_term_format(bad, "bad") || check_term_format(good, "good"))
+		return -1;
+
+	fp = fopen(git_path_bisect_terms(), "w");
+	if (!fp)
+		return error_errno(_("could not open the file BISECT_TERMS"));
+
+	res = fprintf(fp, "%s\n%s\n", bad, good);
+	res |= fclose(fp);
+	return (res < 0) ? -1 : 0;
+}
+
+static int is_expected_rev(const char *expected_hex)
+{
+	struct strbuf actual_hex = STRBUF_INIT;
+	int res = 0;
+	if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
+		strbuf_trim(&actual_hex);
+		res = !strcmp(actual_hex.buf, expected_hex);
+	}
+	strbuf_release(&actual_hex);
+	return res;
+}
+
+static void check_expected_revs(const char **revs, int rev_nr)
+{
+	int i;
+
+	for (i = 0; i < rev_nr; i++) {
+		if (!is_expected_rev(revs[i])) {
+			unlink_or_warn(git_path_bisect_ancestors_ok());
+			unlink_or_warn(git_path_bisect_expected_rev());
+		}
+	}
+}
+
+static int bisect_reset(const char *commit)
+{
+	struct strbuf branch = STRBUF_INIT;
+
+	if (!commit) {
+		if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
+			printf(_("We are not bisecting.\n"));
+			return 0;
+		}
+		strbuf_rtrim(&branch);
+	} else {
+		struct object_id oid;
+
+		if (get_oid_commit(commit, &oid))
+			return error(_("'%s' is not a valid commit"), commit);
+		strbuf_addstr(&branch, commit);
+	}
+
+	if (!file_exists(git_path_bisect_head())) {
+		struct argv_array argv = ARGV_ARRAY_INIT;
+
+		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 -1;
+		}
+		argv_array_clear(&argv);
+	}
+
+	strbuf_release(&branch);
+	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 res = 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 {
+		res = error(_("Bad bisect_write argument: %s"), state);
+		goto finish;
+	}
+
+	if (get_oid(rev, &oid)) {
+		res = 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)) {
+		res = -1;
+		goto finish;
+	}
+
+	fp = fopen(git_path_bisect_log(), "a");
+	if (!fp) {
+		res = 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 res;
+}
+
+static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
+{
+	int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());
+
+	if (one_of(cmd, "skip", "start", "terms", NULL))
+		return 0;
+
+	if (has_term_file && strcmp(cmd, terms->term_bad) &&
+	    strcmp(cmd, terms->term_good))
+		return error(_("Invalid command: you're currently in a "
+				"%s/%s bisect"), terms->term_bad,
+				terms->term_good);
+
+	if (!has_term_file) {
+		if (one_of(cmd, "bad", "good", NULL)) {
+			set_terms(terms, "bad", "good");
+			return write_terms(terms->term_bad, terms->term_good);
+		}
+		if (one_of(cmd, "new", "old", NULL)) {
+			set_terms(terms, "new", "old");
+			return write_terms(terms->term_bad, terms->term_good);
+		}
+	}
+
+	return 0;
+}
+
+static int mark_good(const char *refname, const struct object_id *oid,
+		     int flag, void *cb_data)
+{
+	int *m_good = (int *)cb_data;
+	*m_good = 0;
+	return 1;
+}
+
+static const char need_bad_and_good_revision_warning[] =
+	N_("You need to give me at least one %s and %s revision.\n"
+	   "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
+
+static const char need_bisect_start_warning[] =
+	N_("You need to start by \"git bisect start\".\n"
+	   "You then need to give me at least one %s and %s revision.\n"
+	   "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
+
+static int decide_next(const struct bisect_terms *terms,
+		       const char *current_term, int missing_good,
+		       int missing_bad)
+{
+	if (!missing_good && !missing_bad)
+		return 0;
+	if (!current_term)
+		return -1;
+
+	if (missing_good && !missing_bad &&
+	    !strcmp(current_term, terms->term_good)) {
+		char *yesno;
+		/*
+		 * have bad (or new) but not good (or old). We could bisect
+		 * although this is less optimum.
+		 */
+		warning(_("bisecting only with a %s commit"), terms->term_bad);
+		if (!isatty(0))
+			return 0;
+		/*
+		 * TRANSLATORS: Make sure to include [Y] and [n] in your
+		 * translation. The program will only accept English input
+		 * at this point.
+		 */
+		yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
+		if (starts_with(yesno, "N") || starts_with(yesno, "n"))
+			return -1;
+		return 0;
+	}
+
+	if (!is_empty_or_missing_file(git_path_bisect_start()))
+		return error(_(need_bad_and_good_revision_warning),
+			     vocab_bad, vocab_good, vocab_bad, vocab_good);
+	else
+		return error(_(need_bisect_start_warning),
+			     vocab_good, vocab_bad, vocab_good, vocab_bad);
+}
+
+static int bisect_next_check(const struct bisect_terms *terms,
+			     const char *current_term)
+{
+	int missing_good = 1, missing_bad = 1;
+	char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
+	char *good_glob = xstrfmt("%s-*", terms->term_good);
+
+	if (ref_exists(bad_ref))
+		missing_bad = 0;
+
+	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
+			     (void *) &missing_good);
+
+	free(good_glob);
+	free(bad_ref);
+
+	return decide_next(terms, current_term, missing_good, missing_bad);
+}
+
+static int get_terms(struct bisect_terms *terms)
+{
+	struct strbuf str = STRBUF_INIT;
+	FILE *fp = NULL;
+	int res = 0;
+
+	fp = fopen(git_path_bisect_terms(), "r");
+	if (!fp) {
+		res = -1;
+		goto finish;
+	}
+
+	free_terms(terms);
+	strbuf_getline_lf(&str, fp);
+	terms->term_bad = strbuf_detach(&str, NULL);
+	strbuf_getline_lf(&str, fp);
+	terms->term_good = strbuf_detach(&str, NULL);
+
+finish:
+	if (fp)
+		fclose(fp);
+	strbuf_release(&str);
+	return res;
+}
+
+static int bisect_terms(struct bisect_terms *terms, const char *option)
+{
+	if (get_terms(terms))
+		return error(_("no terms defined"));
+
+	if (option == NULL) {
+		printf(_("Your current terms are %s for the old state\n"
+			 "and %s for the new state.\n"),
+		       terms->term_good, terms->term_bad);
+		return 0;
+	}
+	if (one_of(option, "--term-good", "--term-old", NULL))
+		printf("%s\n", terms->term_good);
+	else if (one_of(option, "--term-bad", "--term-new", NULL))
+		printf("%s\n", terms->term_bad);
+	else
+		return error(_("invalid argument %s for 'git bisect terms'.\n"
+			       "Supported options are: "
+			       "--term-good|--term-old and "
+			       "--term-bad|--term-new."), option);
+
+	return 0;
+}
+
+static int bisect_append_log_quoted(const char **argv)
+{
+	int res = 0;
+	FILE *fp = fopen(git_path_bisect_log(), "a");
+	struct strbuf orig_args = STRBUF_INIT;
+
+	if (!fp)
+		return -1;
+
+	if (fprintf(fp, "git bisect start") < 1) {
+		res = -1;
+		goto finish;
+	}
+
+	sq_quote_argv(&orig_args, argv);
+	if (fprintf(fp, "%s\n", orig_args.buf) < 1)
+		res = -1;
+
+finish:
+	fclose(fp);
+	strbuf_release(&orig_args);
+	return res;
+}
+
+static int bisect_start(struct bisect_terms *terms, int no_checkout,
+			const char **argv, int argc)
+{
+	int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
+	int flags, pathspec_pos, res = 0;
+	struct string_list revs = STRING_LIST_INIT_DUP;
+	struct string_list states = STRING_LIST_INIT_DUP;
+	struct strbuf start_head = STRBUF_INIT;
+	struct strbuf bisect_names = STRBUF_INIT;
+	struct object_id head_oid;
+	struct object_id oid;
+	const char *head;
+
+	if (is_bare_repository())
+		no_checkout = 1;
+
+	/*
+	 * Check for one bad and then some good revisions
+	 */
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(argv[i], "--")) {
+			has_double_dash = 1;
+			break;
+		}
+	}
+
+	for (i = 0; i < argc; i++) {
+		const char *arg = argv[i];
+		if (!strcmp(argv[i], "--")) {
+			break;
+		} else if (!strcmp(arg, "--no-checkout")) {
+			no_checkout = 1;
+		} else if (!strcmp(arg, "--term-good") ||
+			 !strcmp(arg, "--term-old")) {
+			must_write_terms = 1;
+			free((void *) terms->term_good);
+			terms->term_good = xstrdup(argv[++i]);
+		} else if (skip_prefix(arg, "--term-good=", &arg) ||
+			   skip_prefix(arg, "--term-old=", &arg)) {
+			must_write_terms = 1;
+			free((void *) terms->term_good);
+			terms->term_good = xstrdup(arg);
+		} else if (!strcmp(arg, "--term-bad") ||
+			 !strcmp(arg, "--term-new")) {
+			must_write_terms = 1;
+			free((void *) terms->term_bad);
+			terms->term_bad = xstrdup(argv[++i]);
+		} else if (skip_prefix(arg, "--term-bad=", &arg) ||
+			   skip_prefix(arg, "--term-new=", &arg)) {
+			must_write_terms = 1;
+			free((void *) terms->term_bad);
+			terms->term_bad = xstrdup(arg);
+		} else if (starts_with(arg, "--") &&
+			 !one_of(arg, "--term-good", "--term-bad", NULL)) {
+			return error(_("unrecognized option: '%s'"), arg);
+		} else {
+			char *commit_id = xstrfmt("%s^{commit}", arg);
+			if (get_oid(commit_id, &oid) && has_double_dash)
+				die(_("'%s' does not appear to be a valid "
+				      "revision"), arg);
+
+			string_list_append(&revs, oid_to_hex(&oid));
+			free(commit_id);
+		}
+	}
+	pathspec_pos = i;
+
+	/*
+	 * The user ran "git bisect start <sha1> <sha1>", hence did not
+	 * explicitly specify the terms, but we are already starting to
+	 * set references named with the default terms, and won't be able
+	 * to change afterwards.
+	 */
+	if (revs.nr)
+		must_write_terms = 1;
+	for (i = 0; i < revs.nr; i++) {
+		if (bad_seen) {
+			string_list_append(&states, terms->term_good);
+		} else {
+			bad_seen = 1;
+			string_list_append(&states, terms->term_bad);
+		}
+	}
+
+	/*
+	 * Verify HEAD
+	 */
+	head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
+	if (!head)
+		if (get_oid("HEAD", &head_oid))
+			return error(_("bad HEAD - I need a HEAD"));
+
+	/*
+	 * Check if we are bisecting
+	 */
+	if (!is_empty_or_missing_file(git_path_bisect_start())) {
+		/* Reset to the rev from where we started */
+		strbuf_read_file(&start_head, git_path_bisect_start(), 0);
+		strbuf_trim(&start_head);
+		if (!no_checkout) {
+			struct argv_array argv = ARGV_ARRAY_INIT;
+
+			argv_array_pushl(&argv, "checkout", start_head.buf,
+					 "--", NULL);
+			if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
+				res = error(_("checking out '%s' failed."
+						 " Try 'git bisect start "
+						 "<valid-branch>'."),
+					       start_head.buf);
+				goto finish;
+			}
+		}
+	} else {
+		/* Get the rev from where we start. */
+		if (!get_oid(head, &head_oid) &&
+		    !starts_with(head, "refs/heads/")) {
+			strbuf_reset(&start_head);
+			strbuf_addstr(&start_head, oid_to_hex(&head_oid));
+		} else if (!get_oid(head, &head_oid) &&
+			   skip_prefix(head, "refs/heads/", &head)) {
+			/*
+			 * This error message should only be triggered by
+			 * cogito usage, and cogito users should understand
+			 * it relates to cg-seek.
+			 */
+			if (!is_empty_or_missing_file(git_path_head_name()))
+				return error(_("won't bisect on cg-seek'ed tree"));
+			strbuf_addstr(&start_head, head);
+		} else {
+			return error(_("bad HEAD - strange symbolic ref"));
+		}
+	}
+
+	/*
+	 * Get rid of any old bisect state.
+	 */
+	if (bisect_clean_state())
+		return -1;
+
+	/*
+	 * In case of mistaken revs or checkout error, or signals received,
+	 * "bisect_auto_next" below may exit or misbehave.
+	 * We have to trap this to be able to clean up using
+	 * "bisect_clean_state".
+	 */
+
+	/*
+	 * Write new start state
+	 */
+	write_file(git_path_bisect_start(), "%s\n", start_head.buf);
+
+	if (no_checkout) {
+		if (get_oid(start_head.buf, &oid) < 0) {
+			res = error(_("invalid ref: '%s'"), start_head.buf);
+			goto finish;
+		}
+		if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
+			       UPDATE_REFS_MSG_ON_ERR)) {
+			res = -1;
+			goto finish;
+		}
+	}
+
+	if (pathspec_pos < argc - 1)
+		sq_quote_argv(&bisect_names, argv + pathspec_pos);
+	write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
+
+	for (i = 0; i < states.nr; i++)
+		if (bisect_write(states.items[i].string,
+				 revs.items[i].string, terms, 1)) {
+			res = -1;
+			goto finish;
+		}
+
+	if (must_write_terms && write_terms(terms->term_bad,
+					    terms->term_good)) {
+		res = -1;
+		goto finish;
+	}
+
+	res = bisect_append_log_quoted(argv);
+	if (res)
+		res = -1;
+
+finish:
+	string_list_clear(&revs, 0);
+	string_list_clear(&states, 0);
+	strbuf_release(&start_head);
+	strbuf_release(&bisect_names);
+	return res;
+}
+
+int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
+{
+	enum {
+		NEXT_ALL = 1,
+		WRITE_TERMS,
+		BISECT_CLEAN_STATE,
+		CHECK_EXPECTED_REVS,
+		BISECT_RESET,
+		BISECT_WRITE,
+		CHECK_AND_SET_TERMS,
+		BISECT_NEXT_CHECK,
+		BISECT_TERMS,
+		BISECT_START
+	} cmdmode = 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),
+		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_CMDMODE(0, "check-expected-revs", &cmdmode,
+			 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_CMDMODE(0, "check-and-set-terms", &cmdmode,
+			 N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
+		OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
+			 N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
+		OPT_CMDMODE(0, "bisect-terms", &cmdmode,
+			 N_("print out the bisect terms"), BISECT_TERMS),
+		OPT_CMDMODE(0, "bisect-start", &cmdmode,
+			 N_("start the bisect session"), BISECT_START),
+		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,
+			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
+
+	if (!cmdmode)
+		usage_with_options(git_bisect_helper_usage, options);
+
+	switch (cmdmode) {
+	case NEXT_ALL:
+		res = bisect_next_all(the_repository, prefix, no_checkout);
+		break;
+	case WRITE_TERMS:
+		if (argc != 2)
+			return error(_("--write-terms requires two arguments"));
+		return write_terms(argv[0], argv[1]);
+	case BISECT_CLEAN_STATE:
+		if (argc != 0)
+			return error(_("--bisect-clean-state requires no arguments"));
+		return bisect_clean_state();
+	case CHECK_EXPECTED_REVS:
+		check_expected_revs(argv, argc);
+		return 0;
+	case BISECT_RESET:
+		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;
+	case CHECK_AND_SET_TERMS:
+		if (argc != 3)
+			return error(_("--check-and-set-terms requires 3 arguments"));
+		set_terms(&terms, argv[2], argv[1]);
+		res = check_and_set_terms(&terms, argv[0]);
+		break;
+	case BISECT_NEXT_CHECK:
+		if (argc != 2 && argc != 3)
+			return error(_("--bisect-next-check requires 2 or 3 arguments"));
+		set_terms(&terms, argv[1], argv[0]);
+		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
+		break;
+	case BISECT_TERMS:
+		if (argc > 1)
+			return error(_("--bisect-terms requires 0 or 1 argument"));
+		res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
+		break;
+	case BISECT_START:
+		set_terms(&terms, "bad", "good");
+		res = bisect_start(&terms, no_checkout, argv, argc);
+		break;
+	default:
+		return error("BUG: unknown subcommand '%d'", cmdmode);
+	}
+	free_terms(&terms);
+
+	/*
+	 * Handle early success
+	 * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
+	 */
+	if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE)
+		res = BISECT_OK;
+
+	return abs(res);
+}