# [PATCH v14 25/27] bisect--helper: retire `--bisect-autostart` subcommand

62 messages from 2016-08-23 to 2016-08-30. Participants: Pranit Bauva, Junio C Hamano.
Thread: https://gitlist.dev/t/43909

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 25/27] bisect--helper: retire `--bisect-autostart` subcommand
Message-ID: <01020156b73fe6dd-4714236e-c26d-4ee8-b36e-caf516618d87-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6dd-4714236e-c26d-4ee8-b36e-caf516618d87-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--bisect-autostart` subcommand is no longer used in the shell
script and the function `bisect_autostart()` is called from the C
implementation.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 8982f29..a89e2f7 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -27,7 +27,6 @@ static const char * const git_bisect_helper_usage[] = {
 					      "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
 	N_("git bisect--helper --bisect-next"),
 	N_("git bisect--helper --bisect-auto-next"),
-	N_("git bisect--helper --bisect-autostart"),
 	N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
 	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
 	N_("git bisect--helper --bisect-replay <filename>"),
@@ -974,7 +973,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_START,
 		BISECT_NEXT,
 		BISECT_AUTO_NEXT,
-		BISECT_AUTOSTART,
 		BISECT_STATE,
 		BISECT_LOG,
 		BISECT_REPLAY
@@ -993,8 +991,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("find the next bisection commit"), BISECT_NEXT),
 		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
 			 N_("verify the next bisection state then find the next bisection state"), BISECT_AUTO_NEXT),
-		OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
-			 N_("start the bisection if BISECT_START empty or missing"), BISECT_AUTOSTART),
 		OPT_CMDMODE(0, "bisect-state", &cmdmode,
 			 N_("mark the state of ref (or refs)"), BISECT_STATE),
 		OPT_CMDMODE(0, "bisect-log", &cmdmode,
@@ -1050,13 +1046,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		get_terms(&terms);
 		res = bisect_auto_next(&terms, prefix);
 		break;
-	case BISECT_AUTOSTART:
-		if (argc)
-			die(_("--bisect-autostart requires 0 arguments"));
-		strbuf_addstr(&terms.term_good, "good");
-		strbuf_addstr(&terms.term_bad, "bad");
-		res = bisect_autostart(&terms);
-		break;
 	case BISECT_STATE:
 		if (argc == 0)
 			die(_("--bisect-state requires at least 1 argument"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 13/27] bisect--helper: `bisect_start` shell function partially in C
Message-ID: <01020156b73fe6b9-5e500c96-9bc3-4a6b-beb9-b5988dc9ee85-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6b9-5e500c96-9bc3-4a6b-beb9-b5988dc9ee85-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `bisect_start` shell function partially in C and add
`bisect-start` subcommand to `git bisect--helper` to call it from
git-bisect.sh .

The last part is not converted because it calls another shell function
`bisect_start` shell function will be completed after the `bisect_next`
shell function is ported in C.

Using `--bisect-start` 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 and will be called by some
other methods.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 238 ++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            | 133 +-------------------------
 2 files changed, 238 insertions(+), 133 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 44adf6b..c64996a 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -7,6 +7,7 @@
 #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")
@@ -14,6 +15,8 @@ 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 GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
+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]"),
@@ -24,6 +27,8 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
 	N_("git bisect--helper --bisect-next-check [<term>] <TERM_GOOD> <TERM_BAD"),
 	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
 };
 
@@ -391,6 +396,226 @@ static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
 	return 0;
 }
 
+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;
+	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 strbuf orig_args = STRBUF_INIT;
+	const char *head;
+	unsigned char sha1[20];
+	FILE *fp;
+	struct object_id oid;
+
+	if (is_bare_repository())
+		no_checkout = 1;
+
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(argv[i], "--")) {
+			has_double_dash = 1;
+			break;
+		}
+	}
+
+	for (i = 0; i < argc; i++) {
+		const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
+		if (!strcmp(argv[i], "--")) {
+			has_double_dash = 1;
+			break;
+		} else if (!strcmp(argv[i], "--no-checkout"))
+			no_checkout = 1;
+		else if (!strcmp(argv[i], "--term-good") ||
+			 !strcmp(argv[i], "--term-old")) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_good);
+			strbuf_addstr(&terms->term_good, argv[++i]);
+		} else if (skip_prefix(argv[i], "--term-good=", &argv[i])) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_good);
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (skip_prefix(argv[i], "--term-old=", &argv[i])) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_good);
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (!strcmp(argv[i], "--term-bad") ||
+			 !strcmp(argv[i], "--term-new")) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_bad);
+			strbuf_addstr(&terms->term_bad, argv[++i]);
+		} else if (skip_prefix(argv[i], "--term-bad=", &argv[i])) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_bad);
+			strbuf_addstr(&terms->term_bad, argv[i]);
+		} else if (skip_prefix(argv[i], "--term-new=", &argv[i])) {
+			must_write_terms = 1;
+			strbuf_reset(&terms->term_good);
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (starts_with(argv[i], "--") &&
+			 !one_of(argv[i], "--term-good", "--term-bad", NULL)) {
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			die(_("unrecognised option: '%s'"), argv[i]);
+		} else if (get_oid(commit_id, &oid) && has_double_dash) {
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			die(_("'%s' does not appear to be a valid revision"), argv[i]);
+		} else {
+			string_list_append(&revs, oid_to_hex(&oid));
+		}
+	}
+	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.
+	 */
+	must_write_terms |= !!revs.nr;
+	for (i = 0; i < revs.nr; i++) {
+		if (bad_seen)
+			string_list_append(&states, terms->term_good.buf);
+		else {
+			bad_seen = 1;
+			string_list_append(&states, terms->term_bad.buf);
+		}
+	}
+
+	/*
+	 * Verify HEAD
+	 */
+	head = resolve_ref_unsafe("HEAD", 0, sha1, &flags);
+	if (!head) {
+		if (get_sha1("HEAD", sha1)) {
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			die(_("Bad HEAD - I need a HEAD"));
+		}
+	}
+	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)) {
+				error(_("checking out '%s' failed. Try 'git "
+					"bisect start <valid-branch>'."),
+				      start_head.buf);
+				strbuf_release(&start_head);
+				string_list_clear(&revs, 0);
+				string_list_clear(&states, 0);
+				return -1;
+			}
+		}
+	} else {
+		if (starts_with(head, "refs/heads/") ||
+		    !get_oid_hex(head, &oid) || ref_exists(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())) {
+				strbuf_release(&start_head);
+				string_list_clear(&revs, 0);
+				string_list_clear(&states, 0);
+				die(_("won't bisect on cg-seek'ed tree"));
+			}
+			if (starts_with(head, "refs/heads/")) {
+				strbuf_reset(&start_head);
+				strbuf_addstr(&start_head, head + 11);
+			}
+			else {
+				strbuf_reset(&start_head);
+				strbuf_addstr(&start_head, sha1_to_hex(sha1));
+			}
+		} else {
+			strbuf_release(&start_head);
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			die(_("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) {
+		get_oid(start_head.buf, &oid);
+		if (update_ref(NULL, "BISECT_HEAD", oid.hash, NULL, 0,
+			       UPDATE_REFS_MSG_ON_ERR)) {
+			strbuf_release(&start_head);
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			return -1;
+		}
+	}
+	strbuf_release(&start_head);
+
+	if (pathspec_pos < argc - 1)
+		sq_quote_argv(&bisect_names, argv + pathspec_pos, 0);
+	write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
+	strbuf_release(&bisect_names);
+
+	for (i = 0; i < states.nr; i++) {
+		if (bisect_write(states.items[i].string,
+				  revs.items[i].string, terms, 1)) {
+			string_list_clear(&revs, 0);
+			string_list_clear(&states, 0);
+			return -1;
+		}
+	}
+	string_list_clear(&revs, 0);
+	string_list_clear(&states, 0);
+
+	if (must_write_terms)
+		if (write_terms(terms->term_bad.buf, terms->term_good.buf))
+			return -1;
+
+	fp = fopen(git_path_bisect_log(), "a");
+	if (!fp)
+		return -1;
+
+	if (fprintf(fp, "git bisect start") < 1)
+		return -1;
+
+	sq_quote_argv(&orig_args, argv, 0);
+	if (fprintf(fp, "%s", orig_args.buf) < 0) {
+		strbuf_release(&orig_args);
+		return -1;
+	}
+	strbuf_release(&orig_args);
+	if (fprintf(fp, "\n") < 1) {
+		fclose(fp);
+		return -1;
+	}
+	fclose(fp);
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -402,7 +627,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
-		BISECT_TERMS
+		BISECT_TERMS,
+		BISECT_START
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -424,6 +650,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 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_END()
@@ -432,7 +660,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	bisect_terms_init(&terms);
 
 	argc = parse_options(argc, argv, prefix, options,
-			     git_bisect_helper_usage, PARSE_OPT_KEEP_UNKNOWN);
+			     git_bisect_helper_usage,
+			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
 
 	if (!cmdmode)
 		usage_with_options(git_bisect_helper_usage, options);
@@ -486,6 +715,11 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			die(_("--bisect-terms requires 0 or 1 argument"));
 		res = bisect_terms(&terms, argv, argc);
 		break;
+	case BISECT_START:
+		strbuf_addstr(&terms.term_good, "good");
+		strbuf_addstr(&terms.term_bad, "bad");
+		res = bisect_start(&terms, no_checkout, argv, argc);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index d6c8b5a..f0896b3 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -71,122 +71,7 @@ bisect_autostart() {
 }
 
 bisect_start() {
-	#
-	# Check for one bad and then some good revisions.
-	#
-	has_double_dash=0
-	for arg; do
-		case "$arg" in --) has_double_dash=1; break ;; esac
-	done
-	orig_args=$(git rev-parse --sq-quote "$@")
-	bad_seen=0
-	eval=''
-	must_write_terms=0
-	revs=''
-	if test "z$(git rev-parse --is-bare-repository)" != zfalse
-	then
-		mode=--no-checkout
-	else
-		mode=''
-	fi
-	while [ $# -gt 0 ]; do
-		arg="$1"
-		case "$arg" in
-		--)
-			shift
-			break
-		;;
-		--no-checkout)
-			mode=--no-checkout
-			shift ;;
-		--term-good|--term-old)
-			shift
-			must_write_terms=1
-			TERM_GOOD=$1
-			shift ;;
-		--term-good=*|--term-old=*)
-			must_write_terms=1
-			TERM_GOOD=${1#*=}
-			shift ;;
-		--term-bad|--term-new)
-			shift
-			must_write_terms=1
-			TERM_BAD=$1
-			shift ;;
-		--term-bad=*|--term-new=*)
-			must_write_terms=1
-			TERM_BAD=${1#*=}
-			shift ;;
-		--*)
-			die "$(eval_gettext "unrecognised option: '\$arg'")" ;;
-		*)
-			rev=$(git rev-parse -q --verify "$arg^{commit}") || {
-				test $has_double_dash -eq 1 &&
-				die "$(eval_gettext "'\$arg' does not appear to be a valid revision")"
-				break
-			}
-			revs="$revs $rev"
-			shift
-			;;
-		esac
-	done
-
-	for rev in $revs
-	do
-		# 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.
-		must_write_terms=1
-
-		case $bad_seen in
-		0) state=$TERM_BAD ; bad_seen=1 ;;
-		*) state=$TERM_GOOD ;;
-		esac
-		eval="$eval git bisect--helper --bisect-write '$state' '$rev' '$TERM_GOOD' '$TERM_BAD' 'nolog' &&"
-	done
-	#
-	# Verify HEAD.
-	#
-	head=$(GIT_DIR="$GIT_DIR" git symbolic-ref -q HEAD) ||
-	head=$(GIT_DIR="$GIT_DIR" git rev-parse --verify HEAD) ||
-	die "$(gettext "Bad HEAD - I need a HEAD")"
-
-	#
-	# Check if we are bisecting.
-	#
-	start_head=''
-	if test -s "$GIT_DIR/BISECT_START"
-	then
-		# Reset to the rev from where we started.
-		start_head=$(cat "$GIT_DIR/BISECT_START")
-		if test "z$mode" != "z--no-checkout"
-		then
-			git checkout "$start_head" -- ||
-			die "$(eval_gettext "Checking out '\$start_head' failed. Try 'git bisect reset <valid-branch>'.")"
-		fi
-	else
-		# Get rev from where we start.
-		case "$head" in
-		refs/heads/*|$_x40)
-			# This error message should only be triggered by
-			# cogito usage, and cogito users should understand
-			# it relates to cg-seek.
-			[ -s "$GIT_DIR/head-name" ] &&
-				die "$(gettext "won't bisect on cg-seek'ed tree")"
-			start_head="${head#refs/heads/}"
-			;;
-		*)
-			die "$(gettext "Bad HEAD - strange symbolic ref")"
-			;;
-		esac
-	fi
-
-	#
-	# Get rid of any old bisect state.
-	#
-	git bisect--helper --bisect-clean-state || exit
+	git bisect--helper --bisect-start $@ || exit
 
 	#
 	# Change state.
@@ -197,24 +82,10 @@ bisect_start() {
 	#
 	trap 'git bisect--helper --bisect-clean-state' 0
 	trap 'exit 255' 1 2 3 15
-
-	#
-	# Write new start state.
-	#
-	echo "$start_head" >"$GIT_DIR/BISECT_START" && {
-		test "z$mode" != "z--no-checkout" ||
-		git update-ref --no-deref BISECT_HEAD "$start_head"
-	} &&
-	git rev-parse --sq-quote "$@" >"$GIT_DIR/BISECT_NAMES" &&
-	eval "$eval true" &&
-	if test $must_write_terms -eq 1
-	then
-		git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD"
-	fi &&
-	echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
 	#
 	# Check if we can proceed to the next bisect state.
 	#
+	get_terms
 	bisect_auto_next
 
 	trap '-' 0

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <01020156b73fe6ce-3b204354-849b-40fd-93ff-2ebcf77df91c-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6ce-3b204354-849b-40fd-93ff-2ebcf77df91c-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `bisect_next` and the `bisect_auto_next` shell function
in C and add the subcommands to `git bisect--helper` to call it from
git-bisect.sh .

Along with this conversion of `bisect_start` has also finished and thus
it has been fully ported to C.

A lot of parts of bisect.c uses exit() and these signals are then
trapped in the `bisect_start` function. Since the shell script ceases
its existence it would be necessary to convert those exit() calls to
return statements so that errors can be reported efficiently in C code.

As more and more calls are happening to the subcommands in `git
bisect--helper`, more specifically when `bisect_start $rev` is converted to
`git bisect--helper --bisect-start $rev` it is necessary to dequote the
arguments because of shell to C conversion.

Using `--bisect-next` and `--bisect-auto-start` subcommands is a
temporary 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 and will be called by some other methods.

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                 |  80 ++++++++++++------
 builtin/bisect--helper.c | 206 ++++++++++++++++++++++++++++++++++++++++++-----
 git-bisect.sh            |  74 ++---------------
 3 files changed, 249 insertions(+), 111 deletions(-)

diff --git a/bisect.c b/bisect.c
index 45d598d..68c583b 100644
--- a/bisect.c
+++ b/bisect.c
@@ -618,6 +618,12 @@ static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
 	struct argv_array rev_argv = ARGV_ARRAY_INIT;
 	int i;
 
+	/*
+	 * Since the code is slowly being converted to C, there might be
+	 * instances where the revisions were initialized before. Thus
+	 * we first need to reset it.
+	 */
+	reset_revision_walk();
 	init_revisions(revs, prefix);
 	revs->abbrev = 0;
 	revs->commit_format = CMIT_FMT_UNSPECIFIED;
@@ -644,11 +650,11 @@ static void bisect_common(struct rev_info *revs)
 		mark_edges_uninteresting(revs, NULL);
 }
 
-static void exit_if_skipped_commits(struct commit_list *tried,
+static int exit_if_skipped_commits(struct commit_list *tried,
 				    const struct object_id *bad)
 {
 	if (!tried)
-		return;
+		return 0;
 
 	printf("There are only 'skip'ped commits left to test.\n"
 	       "The first %s commit could be any of:\n", term_bad);
@@ -659,7 +665,7 @@ static void exit_if_skipped_commits(struct commit_list *tried,
 	if (bad)
 		printf("%s\n", oid_to_hex(bad));
 	printf(_("We cannot bisect more!\n"));
-	exit(2);
+	return 2;
 }
 
 static int is_expected_rev(const struct object_id *oid)
@@ -700,7 +706,7 @@ static int bisect_checkout(const unsigned char *bisect_rev, int no_checkout)
 		int res;
 		res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
 		if (res)
-			exit(res);
+			return res;
 	}
 
 	argv_show_branch[1] = bisect_rev_hex;
@@ -729,7 +735,7 @@ static struct commit **get_bad_and_good_commits(int *rev_nr)
 	return rev;
 }
 
-static void handle_bad_merge_base(void)
+static int handle_bad_merge_base(void)
 {
 	if (is_expected_rev(current_bad_oid)) {
 		char *bad_hex = oid_to_hex(current_bad_oid);
@@ -750,17 +756,18 @@ static void handle_bad_merge_base(void)
 				"between %s and [%s].\n"),
 				bad_hex, term_bad, term_good, bad_hex, good_hex);
 		}
-		exit(3);
+		return 3;
 	}
 
 	fprintf(stderr, _("Some %s revs are not ancestor of the %s rev.\n"
 		"git bisect cannot work properly in this case.\n"
 		"Maybe you mistook %s and %s revs?\n"),
 		term_good, term_bad, term_good, term_bad);
-	exit(1);
+	bisect_clean_state();
+	return 1;
 }
 
-static void handle_skipped_merge_base(const unsigned char *mb)
+static int handle_skipped_merge_base(const unsigned char *mb)
 {
 	char *mb_hex = sha1_to_hex(mb);
 	char *bad_hex = oid_to_hex(current_bad_oid);
@@ -773,6 +780,7 @@ static void handle_skipped_merge_base(const unsigned char *mb)
 		"We continue anyway."),
 		bad_hex, good_hex, term_bad, mb_hex, bad_hex);
 	free(good_hex);
+	return 0;
 }
 
 /*
@@ -784,10 +792,10 @@ static void handle_skipped_merge_base(const unsigned char *mb)
  * - If one is "skipped", we can't know but we should warn.
  * - If we don't know, we should check it out and ask the user to test.
  */
-static void check_merge_bases(int no_checkout)
+static int check_merge_bases(int no_checkout)
 {
 	struct commit_list *result;
-	int rev_nr;
+	int rev_nr, res = 0;
 	struct commit **rev = get_bad_and_good_commits(&rev_nr);
 
 	result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
@@ -795,19 +803,25 @@ static void check_merge_bases(int no_checkout)
 	for (; result; result = result->next) {
 		const unsigned char *mb = result->item->object.oid.hash;
 		if (!hashcmp(mb, current_bad_oid->hash)) {
-			handle_bad_merge_base();
+			res = handle_bad_merge_base();
+			break;
 		} else if (0 <= sha1_array_lookup(&good_revs, mb)) {
 			continue;
 		} else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
-			handle_skipped_merge_base(mb);
+			res = handle_skipped_merge_base(mb);
+			break;
 		} else {
 			printf(_("Bisecting: a merge base must be tested\n"));
-			exit(bisect_checkout(mb, no_checkout));
+			res = bisect_checkout(mb, no_checkout);
+			if (!res)
+				exit(0);
+			break;
 		}
 	}
 
 	free(rev);
 	free_commit_list(result);
+	return res;
 }
 
 static int check_ancestors(const char *prefix)
@@ -845,11 +859,11 @@ static int check_ancestors(const char *prefix)
  * If a merge base must be tested by the user, its source code will be
  * checked out to be tested by the user and we will exit.
  */
-static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
+static int check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 {
 	char *filename = git_pathdup("BISECT_ANCESTORS_OK");
 	struct stat st;
-	int fd;
+	int fd, res = 0;
 
 	if (!current_bad_oid)
 		die(_("a %s revision is needed"), term_bad);
@@ -864,7 +878,10 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 
 	/* Check if all good revs are ancestor of the bad rev. */
 	if (check_ancestors(prefix))
-		check_merge_bases(no_checkout);
+		res = check_merge_bases(no_checkout);
+
+	if (res)
+		return res;
 
 	/* Create file BISECT_ANCESTORS_OK. */
 	fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
@@ -873,8 +890,11 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 			      filename);
 	else
 		close(fd);
+
+	return 0;
  done:
 	free(filename);
+	return 0;
 }
 
 /*
@@ -944,7 +964,7 @@ int bisect_next_all(const char *prefix, int no_checkout)
 {
 	struct rev_info revs;
 	struct commit_list *tried;
-	int reaches = 0, all = 0, nr, steps;
+	int reaches = 0, all = 0, nr, steps, res;
 	const unsigned char *bisect_rev;
 	char steps_msg[32];
 
@@ -952,7 +972,9 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	if (read_bisect_refs())
 		die(_("reading bisect refs failed"));
 
-	check_good_are_ancestors_of_bad(prefix, no_checkout);
+	res = check_good_are_ancestors_of_bad(prefix, no_checkout);
+	if (res)
+		return res;
 
 	bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
 	revs.limited = 1;
@@ -964,34 +986,40 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	revs.commits = managed_skipped(revs.commits, &tried);
 
 	if (!revs.commits) {
+		int res;
 		/*
 		 * We should exit here only if the "bad"
 		 * commit is also a "skip" commit.
 		 */
-		exit_if_skipped_commits(tried, NULL);
+		res = exit_if_skipped_commits(tried, NULL);
+		if (res)
+			return res;
 
 		printf(_("%s was both %s and %s\n"),
 		       oid_to_hex(current_bad_oid),
 		       term_good,
 		       term_bad);
-		exit(1);
+		return 1;
 	}
 
 	if (!all) {
 		fprintf(stderr, _("No testable commit found.\n"
 			"Maybe you started with bad path parameters?\n"));
-		exit(4);
+		return 4;
 	}
 
 	bisect_rev = revs.commits->item->object.oid.hash;
 
 	if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
-		exit_if_skipped_commits(tried, current_bad_oid);
+		res = exit_if_skipped_commits(tried, current_bad_oid);
+		if (res)
+			return res;
+
 		printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),
 			term_bad);
 		show_diff_tree(prefix, revs.commits->item);
 		/* This means the bisection process succeeded. */
-		exit(10);
+		return 10;
 	}
 
 	nr = all - reaches - 1;
@@ -1005,7 +1033,11 @@ int bisect_next_all(const char *prefix, int no_checkout)
 		  "Bisecting: %d revisions left to test after this %s\n",
 		  nr), nr, steps_msg);
 
-	return bisect_checkout(bisect_rev, no_checkout);
+	res = bisect_checkout(bisect_rev, no_checkout);
+	if (res)
+		bisect_clean_state();
+
+	return res;
 }
 
 static inline int log2i(int n)
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index c64996a..ef7b3a1 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -8,6 +8,7 @@
 #include "run-command.h"
 #include "prompt.h"
 #include "quote.h"
+#include "revision.h"
 
 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
@@ -29,6 +30,8 @@ static const char * const git_bisect_helper_usage[] = {
 	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>...]"),
+	N_("git bisect--helper --bisect-next"),
+	N_("git bisect--helper --bisect-auto-next"),
 	NULL
 };
 
@@ -396,6 +399,129 @@ static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
 	return 0;
 }
 
+static int register_good_ref(const char *refname,
+			     const struct object_id *oid, int flags,
+			     void *cb_data)
+{
+	struct string_list *good_refs = cb_data;
+	string_list_append(good_refs, oid_to_hex(oid));
+	return 0;
+}
+
+static int bisect_next(struct bisect_terms *terms, const char *prefix)
+{
+	int res, no_checkout;
+
+	/* 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".
+	 */
+	if (bisect_next_check(terms, terms->term_good.buf))
+		return -1;
+
+	no_checkout = !is_empty_or_missing_file(git_path_bisect_head());
+
+	/* Perform all bisection computation, display and checkout */
+	res = bisect_next_all(prefix , no_checkout);
+
+	if (res == 10) {
+		FILE *fp;
+		unsigned char sha1[20];
+		struct commit *commit;
+		struct pretty_print_context pp = {0};
+		struct strbuf commit_name = STRBUF_INIT;
+		char *bad_ref = xstrfmt("refs/bisect/%s",
+					      terms->term_bad.buf);
+		read_ref(bad_ref, sha1);
+		commit = lookup_commit_reference(sha1);
+		format_commit_message(commit, "%s", &commit_name, &pp);
+		fp = fopen(git_path_bisect_log(), "a");
+		if (!fp) {
+			free(bad_ref);
+			strbuf_release(&commit_name);
+			return -1;
+		}
+		if (fprintf(fp, "# first %s commit: [%s] %s\n",
+			    terms->term_bad.buf, sha1_to_hex(sha1),
+			    commit_name.buf) < 1){
+			free(bad_ref);
+			strbuf_release(&commit_name);
+			fclose(fp);
+			return -1;
+		}
+		free(bad_ref);
+		strbuf_release(&commit_name);
+		fclose(fp);
+		return 0;
+	}
+	else if (res == 2) {
+		FILE *fp;
+		struct rev_info revs;
+		struct argv_array rev_argv = ARGV_ARRAY_INIT;
+		struct string_list good_revs = STRING_LIST_INIT_DUP;
+		struct pretty_print_context pp = {0};
+		struct commit *commit;
+		char *term_good = xstrfmt("%s-*", terms->term_good.buf);
+		int i;
+
+		fp = fopen(git_path_bisect_log(), "a");
+		if (!fp) {
+			free(term_good);
+			return -1;
+		}
+		if (fprintf(fp, "# only skipped commits left to test\n") < 1) {
+			free(term_good);
+			fclose(fp);
+			return -1;
+		}
+		for_each_glob_ref_in(register_good_ref, term_good,
+				     "refs/bisect/", (void *) &good_revs);
+
+		free(term_good);
+		argv_array_pushl(&rev_argv, "skipped_commits", "refs/bisect/bad", "--not", NULL);
+		for (i = 0; i < good_revs.nr; i++)
+			argv_array_push(&rev_argv, good_revs.items[i].string);
+
+		/* It is important to reset the flags used by revision walks
+		 * as the previous call to bisect_next_all() in turn
+		 * setups a revision walk.
+		 */
+		reset_revision_walk();
+		init_revisions(&revs, NULL);
+		rev_argv.argc = setup_revisions(rev_argv.argc, rev_argv.argv, &revs, NULL);
+		argv_array_clear(&rev_argv);
+		string_list_clear(&good_revs, 0);
+		if (prepare_revision_walk(&revs)) {
+			die(_("revision walk setup failed\n"));
+		}
+
+		while ((commit = get_revision(&revs)) != NULL) {
+			struct strbuf commit_name = STRBUF_INIT;
+			format_commit_message(commit, "%s",
+					      &commit_name, &pp);
+			fprintf(fp, "# possible first %s commit: "
+				    "[%s] %s\n", terms->term_bad.buf,
+				    oid_to_hex(&commit->object.oid),
+				    commit_name.buf);
+			strbuf_release(&commit_name);
+		}
+
+		fclose(fp);
+		return res;
+	}
+
+	return res;
+}
+
+static int bisect_auto_next(struct bisect_terms *terms, const char *prefix)
+{
+	if (!bisect_next_check(terms, NULL))
+		return bisect_next(terms, prefix);
+
+	return 0;
+}
+
 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			const char **argv, int argc)
 {
@@ -415,47 +541,67 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 		no_checkout = 1;
 
 	for (i = 0; i < argc; i++) {
-		if (!strcmp(argv[i], "--")) {
+		const char *arg;
+		if (starts_with(argv[i], "'"))
+			arg = sq_dequote(xstrdup(argv[i]));
+		else
+			arg = argv[i];
+		if (!strcmp(arg, "--")) {
 			has_double_dash = 1;
 			break;
 		}
 	}
 
 	for (i = 0; i < argc; i++) {
-		const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
+		const char *arg, *commit_id;
+		if (starts_with(argv[i], "'"))
+			arg = sq_dequote(xstrdup(argv[i]));
+		else
+			arg = argv[i];
+		commit_id = xstrfmt("%s^{commit}", arg);
 		if (!strcmp(argv[i], "--")) {
 			has_double_dash = 1;
 			break;
-		} else if (!strcmp(argv[i], "--no-checkout"))
+		} else if (!strcmp(arg, "--no-checkout"))
 			no_checkout = 1;
-		else if (!strcmp(argv[i], "--term-good") ||
-			 !strcmp(argv[i], "--term-old")) {
+		else if (!strcmp(arg, "--term-good") ||
+			 !strcmp(arg, "--term-old")) {
+			const char *next_arg;
+			if (starts_with(argv[++i], "'"))
+				next_arg = sq_dequote(xstrdup(argv[i]));
+			else
+				next_arg = argv[i];
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, argv[++i]);
-		} else if (skip_prefix(argv[i], "--term-good=", &argv[i])) {
+			strbuf_addstr(&terms->term_good, next_arg);
+		} else if (skip_prefix(arg, "--term-good=", &arg)) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, argv[i]);
-		} else if (skip_prefix(argv[i], "--term-old=", &argv[i])) {
+			strbuf_addstr(&terms->term_good, arg);
+		} else if (skip_prefix(arg, "--term-old=", &arg)) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, argv[i]);
-		} else if (!strcmp(argv[i], "--term-bad") ||
-			 !strcmp(argv[i], "--term-new")) {
+			strbuf_addstr(&terms->term_good, arg);
+		} else if (!strcmp(arg, "--term-bad") ||
+			 !strcmp(arg, "--term-new")) {
+			const char *next_arg;
+			if (starts_with(argv[++i], "'"))
+				next_arg = sq_dequote(xstrdup(argv[i]));
+			else
+				next_arg = argv[i];
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_bad);
-			strbuf_addstr(&terms->term_bad, argv[++i]);
-		} else if (skip_prefix(argv[i], "--term-bad=", &argv[i])) {
+			strbuf_addstr(&terms->term_bad, next_arg);
+		} else if (skip_prefix(arg, "--term-bad=", &arg)) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_bad);
-			strbuf_addstr(&terms->term_bad, argv[i]);
-		} else if (skip_prefix(argv[i], "--term-new=", &argv[i])) {
+			strbuf_addstr(&terms->term_bad, arg);
+		} else if (skip_prefix(arg, "--term-new=", &arg)) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, argv[i]);
-		} else if (starts_with(argv[i], "--") &&
-			 !one_of(argv[i], "--term-good", "--term-bad", NULL)) {
+			strbuf_addstr(&terms->term_good, arg);
+		} else if (starts_with(arg, "--") &&
+			 !one_of(arg, "--term-good", "--term-bad", NULL)) {
 			string_list_clear(&revs, 0);
 			string_list_clear(&states, 0);
 			die(_("unrecognised option: '%s'"), argv[i]);
@@ -613,7 +759,7 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 	}
 	fclose(fp);
 
-	return 0;
+	return bisect_auto_next(terms, NULL);
 }
 
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
@@ -628,7 +774,9 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
 		BISECT_TERMS,
-		BISECT_START
+		BISECT_START,
+		BISECT_NEXT,
+		BISECT_AUTO_NEXT,
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -652,6 +800,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("print out the bisect terms"), BISECT_TERMS),
 		OPT_CMDMODE(0, "bisect-start", &cmdmode,
 			 N_("start the bisect session"), BISECT_START),
+		OPT_CMDMODE(0, "bisect-next", &cmdmode,
+			 N_("find the next bisection commit"), BISECT_NEXT),
+		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
+			 N_("verify the next bisection state then find the next bisection state"), BISECT_AUTO_NEXT),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -720,6 +872,18 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&terms.term_bad, "bad");
 		res = bisect_start(&terms, no_checkout, argv, argc);
 		break;
+	case BISECT_NEXT:
+		if (argc)
+			die(_("--bisect-next requires 0 arguments"));
+		get_terms(&terms);
+		res = bisect_next(&terms, prefix);
+		break;
+	case BISECT_AUTO_NEXT:
+		if (argc)
+			die(_("--bisect-auto-next requires 0 arguments"));
+		get_terms(&terms);
+		res = bisect_auto_next(&terms, prefix);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index f0896b3..d574c44 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -63,34 +63,13 @@ bisect_autostart() {
 			[Nn]*)
 				exit ;;
 			esac
-			bisect_start
+			git bisect--helper --bisect-start
 		else
 			exit 1
 		fi
 	}
 }
 
-bisect_start() {
-	git bisect--helper --bisect-start $@ || exit
-
-	#
-	# Change state.
-	# In case of mistaken revs or checkout error, or signals received,
-	# "bisect_auto_next" below may exit or misbehave.
-	# We have to trap this to be able to clean up using
-	# "bisect_clean_state".
-	#
-	trap 'git bisect--helper --bisect-clean-state' 0
-	trap 'exit 255' 1 2 3 15
-	#
-	# Check if we can proceed to the next bisect state.
-	#
-	get_terms
-	bisect_auto_next
-
-	trap '-' 0
-}
-
 bisect_skip() {
 	all=''
 	for arg in "$@"
@@ -109,6 +88,7 @@ bisect_skip() {
 bisect_state() {
 	bisect_autostart
 	state=$1
+	get_terms
 	git bisect--helper --check-and-set-terms $state $TERM_GOOD $TERM_BAD || exit
 	get_terms
 	case "$#,$state" in
@@ -139,45 +119,7 @@ bisect_state() {
 	*)
 		usage ;;
 	esac
-	bisect_auto_next
-}
-
-bisect_auto_next() {
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD && bisect_next || :
-}
-
-bisect_next() {
-	case "$#" in 0) ;; *) usage ;; esac
-	bisect_autostart
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD $TERM_GOOD|| exit
-
-	# Perform all bisection computation, display and checkout
-	git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
-	res=$?
-
-	# Check if we should exit because bisection is finished
-	if test $res -eq 10
-	then
-		bad_rev=$(git show-ref --hash --verify refs/bisect/$TERM_BAD)
-		bad_commit=$(git show-branch $bad_rev)
-		echo "# first $TERM_BAD commit: $bad_commit" >>"$GIT_DIR/BISECT_LOG"
-		exit 0
-	elif test $res -eq 2
-	then
-		echo "# only skipped commits left to test" >>"$GIT_DIR/BISECT_LOG"
-		good_revs=$(git for-each-ref --format="%(objectname)" "refs/bisect/$TERM_GOOD-*")
-		for skipped in $(git rev-list refs/bisect/$TERM_BAD --not $good_revs)
-		do
-			skipped_commit=$(git show-branch $skipped)
-			echo "# possible first $TERM_BAD commit: $skipped_commit" >>"$GIT_DIR/BISECT_LOG"
-		done
-		exit $res
-	fi
-
-	# Check for an error in the bisection process
-	test $res -ne 0 && exit $res
-
-	return 0
+	git bisect--helper --bisect-auto-next || exit
 }
 
 bisect_visualize() {
@@ -221,8 +163,7 @@ bisect_replay () {
 		get_terms
 		case "$command" in
 		start)
-			cmd="bisect_start $rev"
-			eval "$cmd" ;;
+			eval "git bisect--helper --bisect-start $rev" ;;
 		"$TERM_GOOD"|"$TERM_BAD"|skip)
 			git bisect--helper --bisect-write "$command" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit;;
 		terms)
@@ -231,7 +172,7 @@ bisect_replay () {
 			die "$(gettext "?? what are you talking about?")" ;;
 		esac
 	done <"$file"
-	bisect_auto_next
+	git bisect--helper --bisect-auto-next
 }
 
 bisect_run () {
@@ -319,14 +260,15 @@ case "$#" in
 	help)
 		git bisect -h ;;
 	start)
-		bisect_start "$@" ;;
+		git bisect--helper --bisect-start "$@" ;;
 	bad|good|new|old|"$TERM_BAD"|"$TERM_GOOD")
 		bisect_state "$cmd" "$@" ;;
 	skip)
 		bisect_skip "$@" ;;
 	next)
 		# Not sure we want "next" at the UI level anymore.
-		bisect_next "$@" ;;
+		get_terms
+		git bisect--helper --bisect-next "$@" || exit ;;
 	visualize|view)
 		bisect_visualize "$@" ;;
 	reset)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 16/27] bisect--helper: retire `--next-all` subcommand
Message-ID: <01020156b73fe6cf-0e14441e-a8cf-4236-8da4-f6c0fd347ad5-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6cf-0e14441e-a8cf-4236-8da4-f6c0fd347ad5-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--next-all` subcommand is no longer used in the shell script and
the function `bisect_next_all()` is called from the C implementation of
`bisect_next()`.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index e351794..8cbcc3b 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -20,7 +20,6 @@ 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-reset [<commit>]"),
 	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
@@ -764,8 +763,7 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
-		NEXT_ALL = 1,
-		WRITE_TERMS,
+		WRITE_TERMS = 1,
 		BISECT_RESET,
 		CHECK_EXPECTED_REVS,
 		BISECT_WRITE,
@@ -778,8 +776,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	} cmdmode = 0;
 	int no_checkout = 0, res = 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-reset", &cmdmode,
@@ -816,8 +812,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 
 	switch (cmdmode) {
 	int nolog;
-	case NEXT_ALL:
-		return bisect_next_all(prefix, no_checkout);
 	case WRITE_TERMS:
 		if (argc != 2)
 			die(_("--write-terms requires two arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 06/27] wrapper: move is_empty_file() and rename it as is_empty_or_missing_file()
Message-ID: <01020156b73fe673-7ca3a15e-3a63-4ea9-9c8b-b57dc0ea2b0e-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe673-7ca3a15e-3a63-4ea9-9c8b-b57dc0ea2b0e-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
is_empty_file() can help to refactor a lot of code. This will be very
helpful in porting "git bisect" to C.

Suggested-by: Torsten Bögershausen <tboegi@web.de>
Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/am.c | 20 ++------------------
 cache.h      |  3 +++
 wrapper.c    | 13 +++++++++++++
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 739b34d..9e1e9d6 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -30,22 +30,6 @@
 #include "mailinfo.h"
 
 /**
- * Returns 1 if the file is empty or does not exist, 0 otherwise.
- */
-static int is_empty_file(const char *filename)
-{
-	struct stat st;
-
-	if (stat(filename, &st) < 0) {
-		if (errno == ENOENT)
-			return 1;
-		die_errno(_("could not stat %s"), filename);
-	}
-
-	return !st.st_size;
-}
-
-/**
  * Returns the length of the first line of msg.
  */
 static int linelen(const char *msg)
@@ -1324,7 +1308,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 		goto finish;
 	}
 
-	if (is_empty_file(am_path(state, "patch"))) {
+	if (is_empty_or_missing_file(am_path(state, "patch"))) {
 		printf_ln(_("Patch is empty. Was it split wrong?"));
 		die_user_resolve(state);
 	}
@@ -1896,7 +1880,7 @@ static void am_run(struct am_state *state, int resume)
 		resume = 0;
 	}
 
-	if (!is_empty_file(am_path(state, "rewritten"))) {
+	if (!is_empty_or_missing_file(am_path(state, "rewritten"))) {
 		assert(state->rebasing);
 		copy_notes_for_rebase(state);
 		run_post_rewrite_hook(state);
diff --git a/cache.h b/cache.h
index b780a91..49f214b 100644
--- a/cache.h
+++ b/cache.h
@@ -1916,4 +1916,7 @@ void sleep_millisec(int millisec);
  */
 void safe_create_dir(const char *dir, int share);
 
+/* Return 1 if the file is empty or does not exists, 0 otherwise. */
+extern int is_empty_or_missing_file(const char *filename);
+
 #endif /* CACHE_H */
diff --git a/wrapper.c b/wrapper.c
index e7f1979..78f6431 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -679,3 +679,16 @@ void sleep_millisec(int millisec)
 {
 	poll(NULL, 0, millisec);
 }
+
+int is_empty_or_missing_file(const char *filename)
+{
+	struct stat st;
+
+	if (stat(filename, &st) < 0) {
+		if (errno == ENOENT)
+			return 1;
+		die_errno(_("could not stat %s"), filename);
+	}
+
+	return !st.st_size;
+}

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 27/27] bisect--helper: remove the dequote in bisect_start()
Message-ID: <01020156b73fe6e4-d45cf1f7-03a3-4566-95d1-73788c5ab2f9-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6e4-d45cf1f7-03a3-4566-95d1-73788c5ab2f9-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Dequoting the arguments was introduced in 25b48b5c to port the function
`bisect_next()` but after the `bisect_replay()` porting, the dequoting
is carried out itself when it passes the arguments to `bisect_start()`
in a simpler way thus dequoting again isn't required. So remove the
extra "deqouting" code introduced by the commit 25b48b5c.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 59 ++++++++++++++++--------------------------------
 1 file changed, 20 insertions(+), 39 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 7577b69e..8bf495c 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -541,67 +541,48 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 		no_checkout = 1;
 
 	for (i = 0; i < argc; i++) {
-		const char *arg;
-		if (starts_with(argv[i], "'"))
-			arg = sq_dequote(xstrdup(argv[i]));
-		else
-			arg = argv[i];
-		if (!strcmp(arg, "--")) {
+		if (!strcmp(argv[i], "--")) {
 			has_double_dash = 1;
 			break;
 		}
 	}
 
 	for (i = 0; i < argc; i++) {
-		const char *arg, *commit_id;
-		if (starts_with(argv[i], "'"))
-			arg = sq_dequote(xstrdup(argv[i]));
-		else
-			arg = argv[i];
-		commit_id = xstrfmt("%s^{commit}", arg);
+		const char  *commit_id;
+		commit_id = xstrfmt("%s^{commit}", argv[i]);
 		if (!strcmp(argv[i], "--")) {
 			has_double_dash = 1;
 			break;
-		} else if (!strcmp(arg, "--no-checkout"))
+		} else if (!strcmp(argv[i], "--no-checkout"))
 			no_checkout = 1;
-		else if (!strcmp(arg, "--term-good") ||
-			 !strcmp(arg, "--term-old")) {
-			const char *next_arg;
-			if (starts_with(argv[++i], "'"))
-				next_arg = sq_dequote(xstrdup(argv[i]));
-			else
-				next_arg = argv[i];
+		else if (!strcmp(argv[i], "--term-good") ||
+			 !strcmp(argv[i], "--term-old")) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, next_arg);
-		} else if (skip_prefix(arg, "--term-good=", &arg)) {
+			strbuf_addstr(&terms->term_good, argv[++i]);
+		} else if (skip_prefix(argv[i], "--term-good=", &argv[i])) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, arg);
-		} else if (skip_prefix(arg, "--term-old=", &arg)) {
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (skip_prefix(argv[i], "--term-old=", &argv[i])) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, arg);
-		} else if (!strcmp(arg, "--term-bad") ||
-			 !strcmp(arg, "--term-new")) {
-			const char *next_arg;
-			if (starts_with(argv[++i], "'"))
-				next_arg = sq_dequote(xstrdup(argv[i]));
-			else
-				next_arg = argv[i];
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (!strcmp(argv[i], "--term-bad") ||
+			 !strcmp(argv[i], "--term-new")) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_bad);
-			strbuf_addstr(&terms->term_bad, next_arg);
-		} else if (skip_prefix(arg, "--term-bad=", &arg)) {
+			strbuf_addstr(&terms->term_bad, argv[++i]);
+		} else if (skip_prefix(argv[i], "--term-bad=", &argv[i])) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_bad);
-			strbuf_addstr(&terms->term_bad, arg);
-		} else if (skip_prefix(arg, "--term-new=", &arg)) {
+			strbuf_addstr(&terms->term_bad, argv[i]);
+		} else if (skip_prefix(argv[i], "--term-new=", &argv[i])) {
 			must_write_terms = 1;
 			strbuf_reset(&terms->term_good);
-			strbuf_addstr(&terms->term_good, arg);
-		} else if (starts_with(arg, "--") &&
-			 !one_of(arg, "--term-good", "--term-bad", NULL)) {
+			strbuf_addstr(&terms->term_good, argv[i]);
+		} else if (starts_with(argv[i], "--") &&
+			 !one_of(argv[i], "--term-good", "--term-bad", NULL)) {
 			string_list_clear(&revs, 0);
 			string_list_clear(&states, 0);
 			die(_("unrecognised option: '%s'"), argv[i]);

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 05/27] t6030: explicitly test for bisection cleanup
Message-ID: <01020156b73fe666-a66817f8-949c-46a0-9eb7-937c5ecd3629-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe666-a66817f8-949c-46a0-9eb7-937c5ecd3629-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Add test to explicitly check that 'git bisect reset' is working as
expected. This is already covered implicitly by the test suite.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>

---
I faced this problem while converting `bisect_clean_state` and the tests
where showing breakages but it wasn't clear as to where exactly are they
breaking. This will patch  will help in that. Also I tested the test
coverage of the test suite before this patch and it covers this (I did
this by purposely changing names of files in git-bisect.sh and running
the test suite).
---
 t/t6030-bisect-porcelain.sh | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 5e5370f..18e7998 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -894,4 +894,21 @@ test_expect_success 'bisect start takes options and revs in any order' '
 	test_cmp expected actual
 '
 
+test_expect_success 'git bisect reset cleans bisection state properly' '
+	git bisect reset &&
+	git bisect start &&
+	git bisect good $HASH1 &&
+	git bisect bad $HASH4 &&
+	git bisect reset &&
+	test -z "$(git for-each-ref "refs/bisect/*")" &&
+	test_path_is_missing "$GIT_DIR/BISECT_EXPECTED_REV" &&
+	test_path_is_missing "$GIT_DIR/BISECT_ANCESTORS_OK" &&
+	test_path_is_missing "$GIT_DIR/BISECT_LOG" &&
+	test_path_is_missing "$GIT_DIR/BISECT_RUN" &&
+	test_path_is_missing "$GIT_DIR/BISECT_TERMS" &&
+	test_path_is_missing "$GIT_DIR/head-name" &&
+	test_path_is_missing "$GIT_DIR/BISECT_HEAD" &&
+	test_path_is_missing "$GIT_DIR/BISECT_START"
+'
+
 test_done

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 19/27] bisect--helper: retire `--check-expected-revs` subcommand
Message-ID: <01020156b73fe6d0-0e2c0b03-999c-4ce9-9432-8cf1a6858c48-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d0-0e2c0b03-999c-4ce9-9432-8cf1a6858c48-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--check-expected-revs` subcommand is no longer used in the shell
script and the function `check_expected_revs()` is called from the C
implementation of `bisect_next()`.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 861c07d..6cc990b 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -870,7 +870,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	enum {
 		WRITE_TERMS = 1,
 		BISECT_RESET,
-		CHECK_EXPECTED_REVS,
 		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
@@ -887,8 +886,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 		OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 			 N_("reset the bisection state"), BISECT_RESET),
-		OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
-			 N_("check for expected revs"), CHECK_EXPECTED_REVS),
 		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,
@@ -933,9 +930,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			die(_("--bisect-reset requires either zero or one arguments"));
 		res = bisect_reset(argc ? argv[0] : NULL);
 		break;
-	case CHECK_EXPECTED_REVS:
-		res = check_expected_revs(argv, argc);
-		break;
 	case BISECT_WRITE:
 		if (argc != 4 && argc != 5)
 			die(_("--bisect-write requires either 4 or 5 arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 01/27] bisect--helper: use OPT_CMDMODE instead of OPT_BOOL
Message-ID: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156a48144f8-c0e127c1-8cd9-4295-ac16-449a54315cac-000000@eu-west-1.amazonses.com>

```
`--next-all` is meant to be used as a subcommand to support multiple
"operation mode" though the current implementation does not contain any
other subcommand along side with `--next-all` but further commits will
include some more subcommands.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 3324229..8111c91 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -10,11 +10,11 @@ static const char * const git_bisect_helper_usage[] = {
 
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
-	int next_all = 0;
+	enum { NEXT_ALL = 1 } cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "next-all", &next_all,
-			 N_("perform 'git bisect next'")),
+		OPT_CMDMODE(0, "next-all", &cmdmode,
+			 N_("perform 'git bisect next'"), NEXT_ALL),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -23,9 +23,14 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options,
 			     git_bisect_helper_usage, 0);
 
-	if (!next_all)
+	if (!cmdmode)
 		usage_with_options(git_bisect_helper_usage, options);
 
-	/* next-all */
-	return bisect_next_all(prefix, no_checkout);
+	switch (cmdmode) {
+	case NEXT_ALL:
+		return bisect_next_all(prefix, no_checkout);
+	default:
+		die("BUG: unknown subcommand '%d'", cmdmode);
+	}
+	return 0;
 }

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <01020156b73fe69a-13136cfb-4daa-4f5d-9b56-537adf2c6942-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe69a-13136cfb-4daa-4f5d-9b56-537adf2c6942-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

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

Using `bisect_reset` subcommand is a temporary measure to port shell
functions to C so as to use the existing test suite. As more functions
are ported, this subcommand would be retired but its implementation will
be called by some other method.

Note: --bisect-clean-state subcommand has not been retired as there are
still a function namely `bisect_start()` which still uses this
subcommand.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            | 28 ++--------------------------
 2 files changed, 49 insertions(+), 27 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index e50934c..9aba094 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -3,17 +3,22 @@
 #include "parse-options.h"
 #include "bisect.h"
 #include "refs.h"
+#include "dir.h"
+#include "argv-array.h"
+#include "run-command.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 GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
 
 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>]"),
 	NULL
 };
 
@@ -84,12 +89,47 @@ static int write_terms(const char *bad, const char *good)
 	return (res < 0) ? -1 : 0;
 }
 
+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, &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();
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		NEXT_ALL = 1,
 		WRITE_TERMS,
-		BISECT_CLEAN_STATE
+		BISECT_CLEAN_STATE,
+		BISECT_RESET
 	} cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
@@ -99,6 +139,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 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, "bisect-reset", &cmdmode,
+			 N_("reset the bisection state"), BISECT_RESET),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -121,6 +163,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		if (argc != 0)
 			die(_("--bisect-clean-state requires no arguments"));
 		return bisect_clean_state();
+	case BISECT_RESET:
+		if (argc > 1)
+			die(_("--bisect-reset requires either zero or one arguments"));
+		return bisect_reset(argc ? argv[0] : NULL);
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index f1202df..442397b 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -409,35 +409,11 @@ bisect_visualize() {
 	eval '"$@"' --bisect -- $(cat "$GIT_DIR/BISECT_NAMES")
 }
 
-bisect_reset() {
-	test -s "$GIT_DIR/BISECT_START" || {
-		gettextln "We are not bisecting."
-		return
-	}
-	case "$#" in
-	0) branch=$(cat "$GIT_DIR/BISECT_START") ;;
-	1) git rev-parse --quiet --verify "$1^{commit}" >/dev/null || {
-			invalid="$1"
-			die "$(eval_gettext "'\$invalid' is not a valid commit")"
-		}
-		branch="$1" ;;
-	*)
-		usage ;;
-	esac
-
-	if ! test -f "$GIT_DIR/BISECT_HEAD" && ! git checkout "$branch" --
-	then
-		die "$(eval_gettext "Could not check out original HEAD '\$branch'.
-Try 'git bisect reset <commit>'.")"
-	fi
-	git bisect--helper --bisect-clean-state || exit
-}
-
 bisect_replay () {
 	file="$1"
 	test "$#" -eq 1 || die "$(gettext "No logfile given")"
 	test -r "$file" || die "$(eval_gettext "cannot read \$file for replaying")"
-	bisect_reset
+	git bisect--helper --bisect-reset || exit
 	while read git bisect command rev
 	do
 		test "$git $bisect" = "git bisect" || test "$git" = "git-bisect" || continue
@@ -627,7 +603,7 @@ case "$#" in
 	visualize|view)
 		bisect_visualize "$@" ;;
 	reset)
-		bisect_reset "$@" ;;
+		git bisect--helper --bisect-reset "$@" ;;
 	replay)
 		bisect_replay "$@" ;;
 	log)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 15/27] bisect--helper: retire `--bisect-clean-state` subcommand
Message-ID: <01020156b73fe6c6-60f4f6c2-9c39-4840-bbbf-18902961d57f-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6c6-60f4f6c2-9c39-4840-bbbf-18902961d57f-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `bisect-clean-state` subcommand is no longer used in the shell
script while the C code uses `bisect_clean_state()` thus remove the
subcommand.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index ef7b3a1..e351794 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -22,7 +22,6 @@ 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 <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
@@ -767,7 +766,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	enum {
 		NEXT_ALL = 1,
 		WRITE_TERMS,
-		BISECT_CLEAN_STATE,
 		BISECT_RESET,
 		CHECK_EXPECTED_REVS,
 		BISECT_WRITE,
@@ -784,8 +782,6 @@ 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_CMDMODE(0, "bisect-reset", &cmdmode,
 			 N_("reset the bisection state"), BISECT_RESET),
 		OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
@@ -827,11 +823,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			die(_("--write-terms requires two arguments"));
 		res = write_terms(argv[0], argv[1]);
 		break;
-	case BISECT_CLEAN_STATE:
-		if (argc != 0)
-			die(_("--bisect-clean-state requires no arguments"));
-		res = bisect_clean_state();
-		break;
 	case BISECT_RESET:
 		if (argc > 1)
 			die(_("--bisect-reset requires either zero or one arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 09/27] bisect--helper: `bisect_write` shell function in C
Message-ID: <01020156b73fe6a7-2e9df745-e3f4-4830-a1af-4acae7964c11-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6a7-2e9df745-e3f4-4830-a1af-4acae7964c11-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
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.

This patch also introduces new methods namely bisect_state_init() and
bisect_terms_release() for easy memory management for the struct
bisect_terms.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 97 ++++++++++++++++++++++++++++++++++++++++++++----
 git-bisect.sh            | 25 ++-----------
 2 files changed, 94 insertions(+), 28 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 711be75..5364960 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -19,9 +19,27 @@ static const char * const git_bisect_helper_usage[] = {
 	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 <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	NULL
 };
 
+struct bisect_terms {
+	struct strbuf term_good;
+	struct strbuf term_bad;
+};
+
+static void bisect_terms_init(struct bisect_terms *terms)
+{
+	strbuf_init(&terms->term_good, 0);
+	strbuf_init(&terms->term_bad, 0);
+}
+
+static void bisect_terms_release(struct bisect_terms *terms)
+{
+	strbuf_release(&terms->term_good);
+	strbuf_release(&terms->term_bad);
+}
+
 /*
  * Check whether the string `term` belongs to the set of strings
  * included in the variable arguments.
@@ -149,6 +167,52 @@ static int check_expected_revs(const char **revs, int rev_nr)
 	return 0;
 }
 
+static int bisect_write(const char *state, const char *rev,
+			const struct bisect_terms *terms, int nolog)
+{
+	struct strbuf tag = STRBUF_INIT;
+	struct strbuf commit_name = STRBUF_INIT;
+	struct object_id oid;
+	struct commit *commit;
+	struct pretty_print_context pp = {0};
+	FILE *fp;
+
+	if (!strcmp(state, terms->term_bad.buf))
+		strbuf_addf(&tag, "refs/bisect/%s", state);
+	else if (one_of(state, terms->term_good.buf, "skip", NULL))
+		strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
+	else
+		return error(_("Bad bisect_write argument: %s"), state);
+
+	if (get_oid(rev, &oid)) {
+		strbuf_release(&tag);
+		return error(_("couldn't get the oid of the rev '%s'"), rev);
+	}
+
+	if (update_ref(NULL, tag.buf, oid.hash, NULL, 0,
+		       UPDATE_REFS_MSG_ON_ERR)) {
+		strbuf_release(&tag);
+		return -1;
+	}
+	strbuf_release(&tag);
+
+	fp = fopen(git_path_bisect_log(), "a");
+	if (!fp)
+		return error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
+
+	commit = lookup_commit_reference(oid.hash);
+	format_commit_message(commit, "%s", &commit_name, &pp);
+	fprintf(fp, "# %s: [%s] %s\n", state, sha1_to_hex(oid.hash),
+		commit_name.buf);
+	strbuf_release(&commit_name);
+
+	if (!nolog)
+		fprintf(fp, "git bisect %s %s\n", state, rev);
+
+	fclose(fp);
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -156,9 +220,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		WRITE_TERMS,
 		BISECT_CLEAN_STATE,
 		BISECT_RESET,
-		CHECK_EXPECTED_REVS
+		CHECK_EXPECTED_REVS,
+		BISECT_WRITE
 	} cmdmode = 0;
-	int no_checkout = 0;
+	int no_checkout = 0, res = 0;
 	struct option options[] = {
 		OPT_CMDMODE(0, "next-all", &cmdmode,
 			 N_("perform 'git bisect next'"), NEXT_ALL),
@@ -170,10 +235,14 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("reset the bisection state"), BISECT_RESET),
 		OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
 			 N_("check for expected revs"), CHECK_EXPECTED_REVS),
+		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_END()
 	};
+	struct bisect_terms terms;
+	bisect_terms_init(&terms);
 
 	argc = parse_options(argc, argv, prefix, options,
 			     git_bisect_helper_usage, 0);
@@ -182,24 +251,38 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		usage_with_options(git_bisect_helper_usage, options);
 
 	switch (cmdmode) {
+	int nolog;
 	case NEXT_ALL:
 		return bisect_next_all(prefix, no_checkout);
 	case WRITE_TERMS:
 		if (argc != 2)
 			die(_("--write-terms requires two arguments"));
-		return write_terms(argv[0], argv[1]);
+		res = write_terms(argv[0], argv[1]);
+		break;
 	case BISECT_CLEAN_STATE:
 		if (argc != 0)
 			die(_("--bisect-clean-state requires no arguments"));
-		return bisect_clean_state();
+		res = bisect_clean_state();
+		break;
 	case BISECT_RESET:
 		if (argc > 1)
 			die(_("--bisect-reset requires either zero or one arguments"));
-		return bisect_reset(argc ? argv[0] : NULL);
+		res = bisect_reset(argc ? argv[0] : NULL);
+		break;
 	case CHECK_EXPECTED_REVS:
-		return check_expected_revs(argv, argc);
+		res = check_expected_revs(argv, argc);
+		break;
+	case BISECT_WRITE:
+		if (argc != 4 && argc != 5)
+			die(_("--bisect-write requires either 4 or 5 arguments"));
+		nolog = (argc == 5) && !strcmp(argv[4], "nolog");
+		strbuf_addstr(&terms.term_good, argv[2]);
+		strbuf_addstr(&terms.term_bad, argv[3]);
+		res = bisect_write(argv[0], argv[1], &terms, nolog);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
-	return 0;
+	bisect_terms_release(&terms);
+	return res;
 }
diff --git a/git-bisect.sh b/git-bisect.sh
index c3e43248..dfdec33 100755
--- 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 ;;
 		*)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 18/27] bisect--helper: `bisect_state` & `bisect_head` shell function in C
Message-ID: <01020156b73fe6d0-ae35967b-556e-4c72-9ae7-363aa1921e90-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d0-ae35967b-556e-4c72-9ae7-363aa1921e90-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

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

Using `--bisect-state` subcommand is a temporary 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 and will be called by some
other methods.

`bisect_head` is called from `bisect_state` thus its not required to
introduce another subcommand.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++
 git-bisect.sh            | 57 +++-----------------------------
 2 files changed, 89 insertions(+), 52 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index a139592..861c07d 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -31,6 +31,8 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-next"),
 	N_("git bisect--helper --bisect-auto-next"),
 	N_("git bisect--helper --bisect-autostart"),
+	N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
+	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
 	NULL
 };
 
@@ -790,6 +792,79 @@ static int bisect_autostart(struct bisect_terms *terms)
 	return 0;
 }
 
+static char *bisect_head(void)
+{
+	if (is_empty_or_missing_file(git_path_bisect_head()))
+		return "HEAD";
+	else
+		return "BISECT_HEAD";
+}
+
+static int bisect_state(struct bisect_terms *terms, const char **argv,
+			int argc)
+{
+	const char *state = argv[0];
+
+	get_terms(terms);
+	if (check_and_set_terms(terms, state))
+		return -1;
+
+	if (!argc)
+		die(_("Please call `--bisect-state` with at least one argument"));
+
+	if (argc == 1 && one_of(state, terms->term_good.buf,
+	    terms->term_bad.buf, "skip", NULL)) {
+		const char *bisected_head = xstrdup(bisect_head());
+		const char *hex[1];
+		unsigned char sha1[20];
+
+		if (get_sha1(bisected_head, sha1))
+			die(_("Bad rev input: %s"), bisected_head);
+		if (bisect_write(state, sha1_to_hex(sha1), terms, 0))
+			return -1;
+
+		*hex = xstrdup(sha1_to_hex(sha1));
+		if (check_expected_revs(hex, 1))
+			return -1;
+		return bisect_auto_next(terms, NULL);
+	}
+
+	if ((argc == 2 && !strcmp(state, terms->term_bad.buf)) ||
+			one_of(state, terms->term_good.buf, "skip", NULL)) {
+		int i;
+		struct string_list hex = STRING_LIST_INIT_DUP;
+
+		for (i = 1; i < argc; i++) {
+			unsigned char sha1[20];
+
+			if (get_sha1(argv[i], sha1)) {
+				string_list_clear(&hex, 0);
+				die(_("Bad rev input: %s"), argv[i]);
+			}
+			string_list_append(&hex, sha1_to_hex(sha1));
+		}
+		for (i = 0; i < hex.nr; i++) {
+			const char **hex_string = (const char **) &hex.items[i].string;
+			if(bisect_write(state, *hex_string, terms, 0)) {
+				string_list_clear(&hex, 0);
+				return -1;
+			}
+			if (check_expected_revs(hex_string, 1)) {
+				string_list_clear(&hex, 0);
+				return -1;
+			}
+		}
+		string_list_clear(&hex, 0);
+		return bisect_auto_next(terms, NULL);
+	}
+
+	if (!strcmp(state, terms->term_bad.buf))
+		die(_("'git bisect %s' can take only one argument."),
+		      terms->term_bad.buf);
+
+	return -1;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -804,6 +879,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_NEXT,
 		BISECT_AUTO_NEXT,
 		BISECT_AUTOSTART,
+		BISECT_STATE
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -829,6 +905,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("verify the next bisection state then find the next bisection state"), BISECT_AUTO_NEXT),
 		OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
 			 N_("start the bisection if BISECT_START empty or missing"), BISECT_AUTOSTART),
+		OPT_CMDMODE(0, "bisect-state", &cmdmode,
+			 N_("mark the state of ref (or refs)"), BISECT_STATE),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -909,6 +987,12 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&terms.term_bad, "bad");
 		res = bisect_autostart(&terms);
 		break;
+	case BISECT_STATE:
+		if (argc == 0)
+			die(_("--bisect-state requires at least 1 argument"));
+		get_terms(&terms);
+		res = bisect_state(&terms, argv, argc);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index cd56551..a9eebbb 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -39,16 +39,6 @@ _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 TERM_BAD=bad
 TERM_GOOD=good
 
-bisect_head()
-{
-	if test -f "$GIT_DIR/BISECT_HEAD"
-	then
-		echo BISECT_HEAD
-	else
-		echo HEAD
-	fi
-}
-
 bisect_skip() {
 	all=''
 	for arg in "$@"
@@ -61,44 +51,7 @@ bisect_skip() {
 		esac
 		all="$all $revs"
 	done
-	eval bisect_state 'skip' $all
-}
-
-bisect_state() {
-	git bisect--helper --bisect-autostart
-	state=$1
-	get_terms
-	git bisect--helper --check-and-set-terms $state $TERM_GOOD $TERM_BAD || exit
-	get_terms
-	case "$#,$state" in
-	0,*)
-		die "Please call 'bisect_state' with at least one argument." ;;
-	1,"$TERM_BAD"|1,"$TERM_GOOD"|1,skip)
-		bisected_head=$(bisect_head)
-		rev=$(git rev-parse --verify "$bisected_head") ||
-			die "$(eval_gettext "Bad rev input: \$bisected_head")"
-		git bisect--helper --bisect-write "$state" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit
-		git bisect--helper --check-expected-revs "$rev" ;;
-	2,"$TERM_BAD"|*,"$TERM_GOOD"|*,skip)
-		shift
-		hash_list=''
-		for rev in "$@"
-		do
-			sha=$(git rev-parse --verify "$rev^{commit}") ||
-				die "$(eval_gettext "Bad rev input: \$rev")"
-			hash_list="$hash_list $sha"
-		done
-		for rev in $hash_list
-		do
-			git bisect--helper --bisect-write "$state" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit
-		done
-		git bisect--helper --check-expected-revs $hash_list ;;
-	*,"$TERM_BAD")
-		die "$(eval_gettext "'git bisect \$TERM_BAD' can take only one argument.")" ;;
-	*)
-		usage ;;
-	esac
-	git bisect--helper --bisect-auto-next || exit
+	eval git bisect--helper --bisect-state 'skip' $all
 }
 
 bisect_visualize() {
@@ -184,8 +137,8 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 			state="$TERM_GOOD"
 		fi
 
-		# We have to use a subshell because "bisect_state" can exit.
-		( bisect_state $state >"$GIT_DIR/BISECT_RUN" )
+		# We have to use a subshell because "--bisect-state" can exit.
+		( git bisect--helper --bisect-state $state >"$GIT_DIR/BISECT_RUN" )
 		res=$?
 
 		cat "$GIT_DIR/BISECT_RUN"
@@ -200,7 +153,7 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 		if [ $res -ne 0 ]
 		then
 			eval_gettextln "bisect run failed:
-'bisect_state \$state' exited with error code \$res" >&2
+'git bisect--helper --bisect-state \$state' exited with error code \$res" >&2
 			exit $res
 		fi
 
@@ -241,7 +194,7 @@ case "$#" in
 	start)
 		git bisect--helper --bisect-start "$@" ;;
 	bad|good|new|old|"$TERM_BAD"|"$TERM_GOOD")
-		bisect_state "$cmd" "$@" ;;
+		git bisect--helper --bisect-state "$cmd" "$@" ;;
 	skip)
 		bisect_skip "$@" ;;
 	next)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 21/27] bisect--helper: `bisect_log` shell function in C
Message-ID: <01020156b73fe6d5-6a363195-eb91-48a0-9a3c-3159fba6d327-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d5-6a363195-eb91-48a0-9a3c-3159fba6d327-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `bisect_log` shell function in C and also add
`--bisect-log` subcommand to `git bisect--helper` to call it from
git-bisect.sh .

Using `--bisect-log` subcommand is a temporary 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 and will be called by some
other method.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 25 ++++++++++++++++++++++++-
 git-bisect.sh            |  7 +------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 1b6e5d8..b57b0c8 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -864,6 +864,21 @@ static int bisect_state(struct bisect_terms *terms, const char **argv,
 	return -1;
 }
 
+static int bisect_log(void)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	if (strbuf_read_file(&buf, git_path_bisect_log(), 256) < 0) {
+		strbuf_release(&buf);
+		return error(_("We are not bisecting.\n"));
+	}
+
+	printf("%s", buf.buf);
+	strbuf_release(&buf);
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -876,7 +891,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_NEXT,
 		BISECT_AUTO_NEXT,
 		BISECT_AUTOSTART,
-		BISECT_STATE
+		BISECT_STATE,
+		BISECT_LOG
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -900,6 +916,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("start the bisection if BISECT_START empty or missing"), BISECT_AUTOSTART),
 		OPT_CMDMODE(0, "bisect-state", &cmdmode,
 			 N_("mark the state of ref (or refs)"), BISECT_STATE),
+		OPT_CMDMODE(0, "bisect-log", &cmdmode,
+			 N_("output the contents of BISECT_LOG"), BISECT_LOG),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -978,6 +996,11 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		get_terms(&terms);
 		res = bisect_state(&terms, argv, argc);
 		break;
+	case BISECT_LOG:
+		if (argc > 1)
+			die(_("--bisect-log requires 0 arguments"));
+		res = bisect_log();
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index a9eebbb..a47e3b5 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -166,11 +166,6 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 	done
 }
 
-bisect_log () {
-	test -s "$GIT_DIR/BISECT_LOG" || die "$(gettext "We are not bisecting.")"
-	cat "$GIT_DIR/BISECT_LOG"
-}
-
 get_terms () {
 	if test -s "$GIT_DIR/BISECT_TERMS"
 	then
@@ -208,7 +203,7 @@ case "$#" in
 	replay)
 		bisect_replay "$@" ;;
 	log)
-		bisect_log ;;
+		git bisect--helper --bisect-log ;;
 	run)
 		bisect_run "$@" ;;
 	terms)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 24/27] bisect--helper: retire `--check-and-set-terms` subcommand
Message-ID: <01020156b73fe6de-17b295fa-cf29-4b4d-a85d-b9b0176213e7-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6de-17b295fa-cf29-4b4d-a85d-b9b0176213e7-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--check-and-set-terms` subcommand is no longer used in the shell
script and the function `check_and_set_terms()` is called from the C
implementation.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 4ab6488..8982f29 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -21,7 +21,6 @@ static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
 
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-reset [<commit>]"),
-	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
 	N_("git bisect--helper --bisect-next-check [<term>] <TERM_GOOD> <TERM_BAD"),
 	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>]"
@@ -970,7 +969,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		BISECT_RESET = 1,
-		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
 		BISECT_TERMS,
 		BISECT_START,
@@ -985,8 +983,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 			 N_("reset the bisection state"), BISECT_RESET),
-		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,
@@ -1025,13 +1021,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			die(_("--bisect-reset requires either zero or one arguments"));
 		res = bisect_reset(argc ? argv[0] : NULL);
 		break;
-	case CHECK_AND_SET_TERMS:
-		if (argc != 3)
-			die(_("--check-and-set-terms requires 3 arguments"));
-		strbuf_addstr(&terms.term_good, argv[1]);
-		strbuf_addstr(&terms.term_bad, argv[2]);
-		res = check_and_set_terms(&terms, argv[0]);
-		break;
 	case BISECT_NEXT_CHECK:
 		if (argc != 2 && argc != 3)
 			die(_("--bisect-next-check requires 2 or 3 arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 17/27] bisect--helper: `bisect_autostart` shell function in C
Message-ID: <01020156b73fe6d7-8b80c663-7c77-469e-811f-40200ec6dbb1-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d7-8b80c663-7c77-469e-811f-40200ec6dbb1-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `bisect_autostart` shell function in C and add the
C implementation from `bisect_next()` which was previously left
uncovered. Also add a subcommand `--bisect-autostart` to
`git bisect--helper` be called from `bisect_state()` from
git-bisect.sh .

Using `--bisect-autostart` subcommand is a temporary 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 and will be called
by `bisect_state()`.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 40 ++++++++++++++++++++++++++++++++++++++++
 git-bisect.sh            | 23 +----------------------
 2 files changed, 41 insertions(+), 22 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 8cbcc3b..a139592 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -30,6 +30,7 @@ static const char * const git_bisect_helper_usage[] = {
 					      "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
 	N_("git bisect--helper --bisect-next"),
 	N_("git bisect--helper --bisect-auto-next"),
+	N_("git bisect--helper --bisect-autostart"),
 	NULL
 };
 
@@ -38,6 +39,8 @@ struct bisect_terms {
 	struct strbuf term_bad;
 };
 
+static int bisect_autostart(struct bisect_terms *terms);
+
 static void bisect_terms_init(struct bisect_terms *terms)
 {
 	strbuf_init(&terms->term_good, 0);
@@ -410,6 +413,7 @@ static int bisect_next(struct bisect_terms *terms, const char *prefix)
 {
 	int res, no_checkout;
 
+	bisect_autostart(terms);
 	/* 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
@@ -760,6 +764,32 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 	return bisect_auto_next(terms, NULL);
 }
 
+static int bisect_autostart(struct bisect_terms *terms)
+{
+	if (is_empty_or_missing_file(git_path_bisect_start())) {
+		const char *yesno;
+		const char *argv[] = {NULL};
+		fprintf(stderr, _("You need to start by \"git bisect "
+				  "start\"\n"));
+
+		if (!isatty(0))
+			return 1;
+
+		/*
+		 * TRANSLATORS: Make sure to include [Y] and [n] in your
+		 * translation. THe program will only accept English input
+		 * at this point.
+		 */
+		yesno = git_prompt(_("Do you want me to do it for you "
+				     "[Y/n]? "), PROMPT_ECHO);
+		if (starts_with(yesno, "n") || starts_with(yesno, "N"))
+			exit(0);
+
+		return bisect_start(terms, 0, argv, 0);
+	}
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -773,6 +803,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_START,
 		BISECT_NEXT,
 		BISECT_AUTO_NEXT,
+		BISECT_AUTOSTART,
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -796,6 +827,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("find the next bisection commit"), BISECT_NEXT),
 		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
 			 N_("verify the next bisection state then find the next bisection state"), BISECT_AUTO_NEXT),
+		OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
+			 N_("start the bisection if BISECT_START empty or missing"), BISECT_AUTOSTART),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -869,6 +902,13 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		get_terms(&terms);
 		res = bisect_auto_next(&terms, prefix);
 		break;
+	case BISECT_AUTOSTART:
+		if (argc)
+			die(_("--bisect-autostart requires 0 arguments"));
+		strbuf_addstr(&terms.term_good, "good");
+		strbuf_addstr(&terms.term_bad, "bad");
+		res = bisect_autostart(&terms);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index d574c44..cd56551 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -49,27 +49,6 @@ bisect_head()
 	fi
 }
 
-bisect_autostart() {
-	test -s "$GIT_DIR/BISECT_START" || {
-		gettextln "You need to start by \"git bisect start\"" >&2
-		if test -t 0
-		then
-			# TRANSLATORS: Make sure to include [Y] and [n] in your
-			# translation. The program will only accept English input
-			# at this point.
-			gettext "Do you want me to do it for you [Y/n]? " >&2
-			read yesno
-			case "$yesno" in
-			[Nn]*)
-				exit ;;
-			esac
-			git bisect--helper --bisect-start
-		else
-			exit 1
-		fi
-	}
-}
-
 bisect_skip() {
 	all=''
 	for arg in "$@"
@@ -86,7 +65,7 @@ bisect_skip() {
 }
 
 bisect_state() {
-	bisect_autostart
+	git bisect--helper --bisect-autostart
 	state=$1
 	get_terms
 	git bisect--helper --check-and-set-terms $state $TERM_GOOD $TERM_BAD || exit

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 12/27] bisect--helper: `get_terms` & `bisect_terms` shell function in C
Message-ID: <01020156b73fe6b3-3ccd9de5-604d-4e7d-919d-a3adae869ebf-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6b3-3ccd9de5-604d-4e7d-919d-a3adae869ebf-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `get_terms` and `bisect_terms` shell function in C and
add `bisect-terms` subcommand to `git bisect--helper` to call it from
git-bisect.sh .

Using `--bisect-terms` 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.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++--
 git-bisect.sh            | 35 ++--------------------------
 2 files changed, 59 insertions(+), 35 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index aca3908..44adf6b 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -23,6 +23,7 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
 	N_("git bisect--helper --bisect-next-check [<term>] <TERM_GOOD> <TERM_BAD"),
+	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
 	NULL
 };
 
@@ -344,6 +345,52 @@ static int bisect_next_check(const struct bisect_terms *terms,
 	return 0;
 }
 
+static int get_terms(struct bisect_terms *terms)
+{
+	FILE *fp;
+	int res;
+	fp = fopen(git_path_bisect_terms(), "r");
+	if (!fp)
+		return -1;
+
+	bisect_terms_reset(terms);
+	res = strbuf_getline(&terms->term_bad, fp) == EOF ||
+	      strbuf_getline(&terms->term_good, fp) == EOF;
+
+	fclose(fp);
+	return res ? -1 : 0;
+}
+
+static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
+{
+	int i;
+
+	if (get_terms(terms)) {
+		fprintf(stderr, _("no terms defined\n"));
+		return -1;
+	}
+	if (argc == 0) {
+		printf(_("Your current terms are %s for the old state\nand "
+		       "%s for the new state.\n"), terms->term_good.buf,
+		       terms->term_bad.buf);
+		return 0;
+	}
+
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(argv[i], "--term-good"))
+			printf("%s\n", terms->term_good.buf);
+		else if (!strcmp(argv[i], "--term-bad"))
+			printf("%s\n", terms->term_bad.buf);
+		else
+			printf(_("invalid argument %s for 'git bisect "
+				  "terms'.\nSupported options are: "
+				  "--term-good|--term-old and "
+				  "--term-bad|--term-new."), argv[i]);
+	}
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -354,7 +401,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		CHECK_EXPECTED_REVS,
 		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
-		BISECT_NEXT_CHECK
+		BISECT_NEXT_CHECK,
+		BISECT_TERMS
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -374,6 +422,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 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_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -382,7 +432,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	bisect_terms_init(&terms);
 
 	argc = parse_options(argc, argv, prefix, options,
-			     git_bisect_helper_usage, 0);
+			     git_bisect_helper_usage, PARSE_OPT_KEEP_UNKNOWN);
 
 	if (!cmdmode)
 		usage_with_options(git_bisect_helper_usage, options);
@@ -431,6 +481,11 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&terms.term_bad, argv[1]);
 		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 		break;
+	case BISECT_TERMS:
+		if (argc > 1)
+			die(_("--bisect-terms requires 0 or 1 argument"));
+		res = bisect_terms(&terms, argv, argc);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index fe6c9d0..d6c8b5a 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -355,7 +355,7 @@ bisect_replay () {
 		"$TERM_GOOD"|"$TERM_BAD"|skip)
 			git bisect--helper --bisect-write "$command" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit;;
 		terms)
-			bisect_terms $rev ;;
+			git bisect--helper --bisect-terms $rev  || exit;;
 		*)
 			die "$(gettext "?? what are you talking about?")" ;;
 		esac
@@ -437,37 +437,6 @@ get_terms () {
 	fi
 }
 
-bisect_terms () {
-	get_terms
-	if ! test -s "$GIT_DIR/BISECT_TERMS"
-	then
-		die "$(gettext "no terms defined")"
-	fi
-	case "$#" in
-	0)
-		gettextln "Your current terms are $TERM_GOOD for the old state
-and $TERM_BAD for the new state."
-		;;
-	1)
-		arg=$1
-		case "$arg" in
-			--term-good|--term-old)
-				printf '%s\n' "$TERM_GOOD"
-				;;
-			--term-bad|--term-new)
-				printf '%s\n' "$TERM_BAD"
-				;;
-			*)
-				die "$(eval_gettext "invalid argument \$arg for 'git bisect terms'.
-Supported options are: --term-good|--term-old and --term-bad|--term-new.")"
-				;;
-		esac
-		;;
-	*)
-		usage ;;
-	esac
-}
-
 case "$#" in
 0)
 	usage ;;
@@ -498,7 +467,7 @@ case "$#" in
 	run)
 		bisect_run "$@" ;;
 	terms)
-		bisect_terms "$@" ;;
+		git bisect--helper --bisect-terms "$@" || exit;;
 	*)
 		usage ;;
 	esac

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 04/27] bisect--helper: `bisect_clean_state` shell function in C
Message-ID: <01020156b73fe66f-bfad6316-39d4-4577-8f75-d1b4b2031263-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe66f-bfad6316-39d4-4577-8f75-d1b4b2031263-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
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 () {

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 20/27] bisect--helper: retire `--write-terms` subcommand
Message-ID: <01020156b73fe6d2-1815fb4e-50a2-4176-900e-9f22c5bfb9ec-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d2-1815fb4e-50a2-4176-900e-9f22c5bfb9ec-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--write-terms` subcommand is no longer used in the shell script and
the function `write_terms()` is called from the C implementation of
`set_terms()` 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>
---
 builtin/bisect--helper.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 6cc990b..1b6e5d8 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -20,7 +20,6 @@ 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 --write-terms <bad_term> <good_term>"),
 	N_("git bisect--helper --bisect-reset [<commit>]"),
 	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
@@ -868,8 +867,7 @@ static int bisect_state(struct bisect_terms *terms, const char **argv,
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
-		WRITE_TERMS = 1,
-		BISECT_RESET,
+		BISECT_RESET = 1,
 		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
@@ -882,8 +880,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
-		OPT_CMDMODE(0, "write-terms", &cmdmode,
-			 N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 		OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 			 N_("reset the bisection state"), BISECT_RESET),
 		OPT_CMDMODE(0, "bisect-write", &cmdmode,
@@ -920,11 +916,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 
 	switch (cmdmode) {
 	int nolog;
-	case WRITE_TERMS:
-		if (argc != 2)
-			die(_("--write-terms requires two arguments"));
-		res = write_terms(argv[0], argv[1]);
-		break;
 	case BISECT_RESET:
 		if (argc > 1)
 			die(_("--bisect-reset requires either zero or one arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 23/27] bisect--helper: retire `--bisect-write` subcommand
Message-ID: <01020156b73fe6d8-0e494417-0873-4f57-894b-fece73e21124-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d8-0e494417-0873-4f57-894b-fece73e21124-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--bisect-write` subcommand is no longer used in the shell script
and the function `bisect_write()` is called from the C implementation.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 9c1108d..4ab6488 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -21,7 +21,6 @@ static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
 
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-reset [<commit>]"),
-	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
 	N_("git bisect--helper --bisect-next-check [<term>] <TERM_GOOD> <TERM_BAD"),
 	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
@@ -971,7 +970,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		BISECT_RESET = 1,
-		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
 		BISECT_NEXT_CHECK,
 		BISECT_TERMS,
@@ -987,8 +985,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		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,
@@ -1024,20 +1020,11 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		usage_with_options(git_bisect_helper_usage, options);
 
 	switch (cmdmode) {
-	int nolog;
 	case BISECT_RESET:
 		if (argc > 1)
 			die(_("--bisect-reset requires either zero or one arguments"));
 		res = bisect_reset(argc ? argv[0] : NULL);
 		break;
-	case BISECT_WRITE:
-		if (argc != 4 && argc != 5)
-			die(_("--bisect-write requires either 4 or 5 arguments"));
-		nolog = (argc == 5) && !strcmp(argv[4], "nolog");
-		strbuf_addstr(&terms.term_good, argv[2]);
-		strbuf_addstr(&terms.term_bad, argv[3]);
-		res = bisect_write(argv[0], argv[1], &terms, nolog);
-		break;
 	case CHECK_AND_SET_TERMS:
 		if (argc != 3)
 			die(_("--check-and-set-terms requires 3 arguments"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 10/27] bisect--helper: `check_and_set_terms` shell function in C
Message-ID: <01020156b73fe6ab-552239e5-6d82-4bef-80b6-06066bdd79c3-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6ab-552239e5-6d82-4bef-80b6-06066bdd79c3-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `check_and_set_terms` shell function in C and add
`check-and-set-terms` subcommand to `git bisect--helper` to call it from
git-bisect.sh

Using `--check-and-set-terms` 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.

check_and_set_terms() sets and receives two global variables namely
TERM_GOOD and TERM_BAD in the shell script. Luckily the file BISECT_TERMS
also contains the value of those variables so its appropriate to evoke the
method get_terms() after calling the subcommand so that it retrieves the
value of TERM_GOOD and TERM_BAD from the file BISECT_TERMS. The two
global variables are passed as arguments to the subcommand.

Also introduce bisect_terms_reset() to empty the contents of `term_good`
and `term_bad` of `struct bisect_terms`.

Also introduce set_terms() to copy the `term_good` and `term_bad` into
`struct bisect_terms` and write it out to the file BISECT_TERMS.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            | 36 ++++-----------------------------
 2 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 5364960..450426c 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -20,6 +20,7 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-clean-state"),
 	N_("git bisect--helper --bisect-reset [<commit>]"),
 	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
+	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
 	NULL
 };
 
@@ -40,6 +41,12 @@ static void bisect_terms_release(struct bisect_terms *terms)
 	strbuf_release(&terms->term_bad);
 }
 
+static void bisect_terms_reset(struct bisect_terms *term)
+{
+	strbuf_reset(&term->term_good);
+	strbuf_reset(&term->term_bad);
+}
+
 /*
  * Check whether the string `term` belongs to the set of strings
  * included in the variable arguments.
@@ -213,6 +220,39 @@ static int bisect_write(const char *state, const char *rev,
 	return 0;
 }
 
+static int set_terms(struct bisect_terms *terms, const char *bad,
+		     const char *good)
+{
+	bisect_terms_reset(terms);
+	strbuf_addstr(&terms->term_good, good);
+	strbuf_addstr(&terms->term_bad, bad);
+	return write_terms(terms->term_bad.buf, terms->term_good.buf);
+}
+
+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.buf) &&
+	    strcmp(cmd, terms->term_good.buf))
+		return error(_("Invalid command: you're currently in a "
+				"%s/%s bisect"), terms->term_bad.buf,
+				terms->term_good.buf);
+
+	if (!has_term_file) {
+		if (one_of(cmd, "bad", "good", NULL))
+			return set_terms(terms, "bad", "good");
+		if (one_of(cmd, "new", "old", NULL))
+			return set_terms(terms, "new", "old");
+	}
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -221,7 +261,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_CLEAN_STATE,
 		BISECT_RESET,
 		CHECK_EXPECTED_REVS,
-		BISECT_WRITE
+		BISECT_WRITE,
+		CHECK_AND_SET_TERMS
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -237,6 +278,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("check for expected revs"), CHECK_EXPECTED_REVS),
 		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_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -280,6 +323,13 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&terms.term_bad, argv[3]);
 		res = bisect_write(argv[0], argv[1], &terms, nolog);
 		break;
+	case CHECK_AND_SET_TERMS:
+		if (argc != 3)
+			die(_("--check-and-set-terms requires 3 arguments"));
+		strbuf_addstr(&terms.term_good, argv[1]);
+		strbuf_addstr(&terms.term_bad, argv[2]);
+		res = check_and_set_terms(&terms, argv[0]);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index dfdec33..bdf2227 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -238,7 +238,8 @@ bisect_skip() {
 bisect_state() {
 	bisect_autostart
 	state=$1
-	check_and_set_terms $state
+	git bisect--helper --check-and-set-terms $state $TERM_GOOD $TERM_BAD || exit
+	get_terms
 	case "$#,$state" in
 	0,*)
 		die "Please call 'bisect_state' with at least one argument." ;;
@@ -390,7 +391,8 @@ bisect_replay () {
 			command="$bisect"
 		fi
 		get_terms
-		check_and_set_terms "$command"
+		git bisect--helper --check-and-set-terms "$command" "$TERM_GOOD" "$TERM_BAD" || exit
+		get_terms
 		case "$command" in
 		start)
 			cmd="bisect_start $rev"
@@ -480,36 +482,6 @@ get_terms () {
 	fi
 }
 
-check_and_set_terms () {
-	cmd="$1"
-	case "$cmd" in
-	skip|start|terms) ;;
-	*)
-		if test -s "$GIT_DIR/BISECT_TERMS" && test "$cmd" != "$TERM_BAD" && test "$cmd" != "$TERM_GOOD"
-		then
-			die "$(eval_gettext "Invalid command: you're currently in a \$TERM_BAD/\$TERM_GOOD bisect.")"
-		fi
-		case "$cmd" in
-		bad|good)
-			if ! test -s "$GIT_DIR/BISECT_TERMS"
-			then
-				TERM_BAD=bad
-				TERM_GOOD=good
-				git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD" || exit
-			fi
-			;;
-		new|old)
-			if ! test -s "$GIT_DIR/BISECT_TERMS"
-			then
-				TERM_BAD=new
-				TERM_GOOD=old
-				git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD" || exit
-			fi
-			;;
-		esac ;;
-	esac
-}
-
 bisect_voc () {
 	case "$1" in
 	bad) echo "bad|new" ;;

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 03/27] bisect--helper: `write_terms` shell function in C
Message-ID: <01020156b73fe658-9c0fcb5f-3dc0-43e4-a1ac-2ef9de7b0ef6-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe658-9c0fcb5f-3dc0-43e4-a1ac-2ef9de7b0ef6-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `write_terms` shell function in C and add a `write-terms`
subcommand to `git bisect--helper` to call it from git-bisect.sh . Also
remove the subcommand `--check-term-format` as it can now be called from
inside the function write_terms() C implementation.

Also `|| exit` is added when calling write-terms subcommand from
git-bisect.sh so as to exit whenever there is an error.

Using `--write-terms` subcommand is a temporary 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 and its implementation will
be called by some other method.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 36 +++++++++++++++++++++++++++++-------
 git-bisect.sh            | 22 +++++++---------------
 2 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index a47f1f2..30e1031 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -4,9 +4,11 @@
 #include "bisect.h"
 #include "refs.h"
 
+static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
+
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --next-all [--no-checkout]"),
-	N_("git bisect--helper --check-term-format <term> <orig_term>"),
+	N_("git bisect--helper --write-terms <bad_term> <good_term>"),
 	NULL
 };
 
@@ -57,18 +59,38 @@ static int check_term_format(const char *term, const char *orig_term)
 	return 0;
 }
 
+static int write_terms(const char *bad, const char *good)
+{
+	FILE *fp;
+	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;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		NEXT_ALL = 1,
-		CHECK_TERM_FMT
+		WRITE_TERMS
 	} cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
 		OPT_CMDMODE(0, "next-all", &cmdmode,
 			 N_("perform 'git bisect next'"), NEXT_ALL),
-		OPT_CMDMODE(0, "check-term-format", &cmdmode,
-			 N_("check format of the term"), CHECK_TERM_FMT),
+		OPT_CMDMODE(0, "write-terms", &cmdmode,
+			 N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -83,10 +105,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	switch (cmdmode) {
 	case NEXT_ALL:
 		return bisect_next_all(prefix, no_checkout);
-	case CHECK_TERM_FMT:
+	case WRITE_TERMS:
 		if (argc != 2)
-			die(_("--check-term-format requires two arguments"));
-		return check_term_format(argv[0], argv[1]);
+			die(_("--write-terms requires two arguments"));
+		return write_terms(argv[0], argv[1]);
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index a727c59..9ef6cb8 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -209,7 +209,7 @@ bisect_start() {
 	eval "$eval true" &&
 	if test $must_write_terms -eq 1
 	then
-		write_terms "$TERM_BAD" "$TERM_GOOD"
+		git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD"
 	fi &&
 	echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
 	#
@@ -557,18 +557,6 @@ get_terms () {
 	fi
 }
 
-write_terms () {
-	TERM_BAD=$1
-	TERM_GOOD=$2
-	if test "$TERM_BAD" = "$TERM_GOOD"
-	then
-		die "$(gettext "please use two different terms")"
-	fi
-	git bisect--helper --check-term-format "$TERM_BAD" bad || exit
-	git bisect--helper --check-term-format "$TERM_GOOD" good || exit
-	printf '%s\n%s\n' "$TERM_BAD" "$TERM_GOOD" >"$GIT_DIR/BISECT_TERMS"
-}
-
 check_and_set_terms () {
 	cmd="$1"
 	case "$cmd" in
@@ -582,13 +570,17 @@ check_and_set_terms () {
 		bad|good)
 			if ! test -s "$GIT_DIR/BISECT_TERMS"
 			then
-				write_terms bad good
+				TERM_BAD=bad
+				TERM_GOOD=good
+				git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD" || exit
 			fi
 			;;
 		new|old)
 			if ! test -s "$GIT_DIR/BISECT_TERMS"
 			then
-				write_terms new old
+				TERM_BAD=new
+				TERM_GOOD=old
+				git bisect--helper --write-terms "$TERM_BAD" "$TERM_GOOD" || exit
 			fi
 			;;
 		esac ;;

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 26/27] bisect--helper: retire `--bisect-auto-next` subcommand
Message-ID: <01020156b73fe6de-dee87e51-6e61-4869-898a-382d382f0366-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6de-dee87e51-6e61-4869-898a-382d382f0366-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
The `--bisect-auto-next` subcommand is no longer used in the shell
script and the function `bisect_auto_next` is called from the C
implementation.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index a89e2f7..7577b69e 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -26,7 +26,6 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
 					      "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
 	N_("git bisect--helper --bisect-next"),
-	N_("git bisect--helper --bisect-auto-next"),
 	N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
 	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
 	N_("git bisect--helper --bisect-replay <filename>"),
@@ -972,7 +971,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_TERMS,
 		BISECT_START,
 		BISECT_NEXT,
-		BISECT_AUTO_NEXT,
 		BISECT_STATE,
 		BISECT_LOG,
 		BISECT_REPLAY
@@ -989,8 +987,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("start the bisect session"), BISECT_START),
 		OPT_CMDMODE(0, "bisect-next", &cmdmode,
 			 N_("find the next bisection commit"), BISECT_NEXT),
-		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
-			 N_("verify the next bisection state then find the next bisection state"), BISECT_AUTO_NEXT),
 		OPT_CMDMODE(0, "bisect-state", &cmdmode,
 			 N_("mark the state of ref (or refs)"), BISECT_STATE),
 		OPT_CMDMODE(0, "bisect-log", &cmdmode,
@@ -1040,12 +1036,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		get_terms(&terms);
 		res = bisect_next(&terms, prefix);
 		break;
-	case BISECT_AUTO_NEXT:
-		if (argc)
-			die(_("--bisect-auto-next requires 0 arguments"));
-		get_terms(&terms);
-		res = bisect_auto_next(&terms, prefix);
-		break;
 	case BISECT_STATE:
 		if (argc == 0)
 			die(_("--bisect-state requires at least 1 argument"));

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 02/27] bisect: rewrite `check_term_format` shell function in C
Message-ID: <01020156b73fe650-9ea6edbf-06df-45b3-ac65-848db7210cff-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe650-9ea6edbf-06df-45b3-ac65-848db7210cff-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `check_term_format` shell function in C and add
a `--check-term-format` subcommand to `git bisect--helper` to call it
from git-bisect.sh

Using `--check-term-format` subcommand is a temporary 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 and its
implementation will be called by some other method/subcommand. For
eg. In conversion of write_terms() of git-bisect.sh, the subcommand will
be removed and instead check_term_format() will be called in its C
implementation while a new subcommand will be introduced for write_terms().

Helped-by: Johannes Schindelein <Johannes.Schindelein@gmx.de>
Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            | 31 ++-----------------------
 2 files changed, 61 insertions(+), 30 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 8111c91..a47f1f2 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -2,19 +2,73 @@
 #include "cache.h"
 #include "parse-options.h"
 #include "bisect.h"
+#include "refs.h"
 
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --next-all [--no-checkout]"),
+	N_("git bisect--helper --check-term-format <term> <orig_term>"),
 	NULL
 };
 
+/*
+ * 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", "replay", "log", "run", 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;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
-	enum { NEXT_ALL = 1 } cmdmode = 0;
+	enum {
+		NEXT_ALL = 1,
+		CHECK_TERM_FMT
+	} cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
 		OPT_CMDMODE(0, "next-all", &cmdmode,
 			 N_("perform 'git bisect next'"), NEXT_ALL),
+		OPT_CMDMODE(0, "check-term-format", &cmdmode,
+			 N_("check format of the term"), CHECK_TERM_FMT),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -29,6 +83,10 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	switch (cmdmode) {
 	case NEXT_ALL:
 		return bisect_next_all(prefix, no_checkout);
+	case CHECK_TERM_FMT:
+		if (argc != 2)
+			die(_("--check-term-format requires two arguments"));
+		return check_term_format(argv[0], argv[1]);
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index ae3cb01..a727c59 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -564,38 +564,11 @@ write_terms () {
 	then
 		die "$(gettext "please use two different terms")"
 	fi
-	check_term_format "$TERM_BAD" bad
-	check_term_format "$TERM_GOOD" good
+	git bisect--helper --check-term-format "$TERM_BAD" bad || exit
+	git bisect--helper --check-term-format "$TERM_GOOD" good || exit
 	printf '%s\n%s\n' "$TERM_BAD" "$TERM_GOOD" >"$GIT_DIR/BISECT_TERMS"
 }
 
-check_term_format () {
-	term=$1
-	git check-ref-format refs/bisect/"$term" ||
-	die "$(eval_gettext "'\$term' is not a valid term")"
-	case "$term" in
-	help|start|terms|skip|next|reset|visualize|replay|log|run)
-		die "$(eval_gettext "can't use the builtin command '\$term' as a term")"
-		;;
-	bad|new)
-		if test "$2" != bad
-		then
-			# In theory, nothing prevents swapping
-			# completely good and bad, but this situation
-			# could be confusing and hasn't been tested
-			# enough. Forbid it for now.
-			die "$(eval_gettext "can't change the meaning of term '\$term'")"
-		fi
-		;;
-	good|old)
-		if test "$2" != good
-		then
-			die "$(eval_gettext "can't change the meaning of term '\$term'")"
-		fi
-		;;
-	esac
-}
-
 check_and_set_terms () {
 	cmd="$1"
 	case "$cmd" in

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 08/27] bisect--helper: `is_expected_rev` & `check_expected_revs` shell function in C
Message-ID: <01020156b73fe69f-6b734e3c-806c-431d-aa52-c96b3783f248-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe69f-6b734e3c-806c-431d-aa52-c96b3783f248-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement `is_expected_rev` & `check_expected_revs` shell function in
C and add a `--check-expected-revs` subcommand to `git bisect--helper` to
call it from git-bisect.sh .

Using `--check-expected-revs` subcommand is a temporary measure to port
shell functions to C so as to use the existing test suite. As more
functions are ported, this subcommand would be retired but its
implementation will be called by some other method.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 33 ++++++++++++++++++++++++++++++++-
 git-bisect.sh            | 20 ++------------------
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 9aba094..711be75 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -123,13 +123,40 @@ static int bisect_reset(const char *commit)
 	return bisect_clean_state();
 }
 
+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) >= 0) {
+		strbuf_trim(&actual_hex);
+		res = !strcmp(actual_hex.buf, expected_hex);
+	}
+	strbuf_release(&actual_hex);
+	return res;
+}
+
+static int 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());
+			return 0;
+		}
+	}
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		NEXT_ALL = 1,
 		WRITE_TERMS,
 		BISECT_CLEAN_STATE,
-		BISECT_RESET
+		BISECT_RESET,
+		CHECK_EXPECTED_REVS
 	} cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
@@ -141,6 +168,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
 		OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 			 N_("reset the bisection state"), BISECT_RESET),
+		OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
+			 N_("check for expected revs"), CHECK_EXPECTED_REVS),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -167,6 +196,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		if (argc > 1)
 			die(_("--bisect-reset requires either zero or one arguments"));
 		return bisect_reset(argc ? argv[0] : NULL);
+	case CHECK_EXPECTED_REVS:
+		return check_expected_revs(argv, argc);
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index 442397b..c3e43248 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -237,22 +237,6 @@ bisect_write() {
 	test -n "$nolog" || echo "git bisect $state $rev" >>"$GIT_DIR/BISECT_LOG"
 }
 
-is_expected_rev() {
-	test -f "$GIT_DIR/BISECT_EXPECTED_REV" &&
-	test "$1" = $(cat "$GIT_DIR/BISECT_EXPECTED_REV")
-}
-
-check_expected_revs() {
-	for _rev in "$@"; do
-		if ! is_expected_rev "$_rev"
-		then
-			rm -f "$GIT_DIR/BISECT_ANCESTORS_OK"
-			rm -f "$GIT_DIR/BISECT_EXPECTED_REV"
-			return
-		fi
-	done
-}
-
 bisect_skip() {
 	all=''
 	for arg in "$@"
@@ -280,7 +264,7 @@ bisect_state() {
 		rev=$(git rev-parse --verify "$bisected_head") ||
 			die "$(eval_gettext "Bad rev input: \$bisected_head")"
 		bisect_write "$state" "$rev"
-		check_expected_revs "$rev" ;;
+		git bisect--helper --check-expected-revs "$rev" ;;
 	2,"$TERM_BAD"|*,"$TERM_GOOD"|*,skip)
 		shift
 		hash_list=''
@@ -294,7 +278,7 @@ bisect_state() {
 		do
 			bisect_write "$state" "$rev"
 		done
-		check_expected_revs $hash_list ;;
+		git bisect--helper --check-expected-revs $hash_list ;;
 	*,"$TERM_BAD")
 		die "$(eval_gettext "'git bisect \$TERM_BAD' can take only one argument.")" ;;
 	*)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 22/27] bisect--helper: `bisect_replay` shell function in C
Message-ID: <01020156b73fe6d7-6cd42223-f46c-4e4c-a15f-516fc13a4521-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6d7-6cd42223-f46c-4e4c-a15f-516fc13a4521-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement the `bisect_replay` shell function in C and also add
`--bisect-replay` subcommand to `git bisect--helper` to call it from
git-bisect.sh

Using `--bisect-replay` subcommand is a temporary 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 and will be called by some
other method.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            |  32 +--------------
 2 files changed, 100 insertions(+), 32 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index b57b0c8..9c1108d 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -32,6 +32,7 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-autostart"),
 	N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
 	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
+	N_("git bisect--helper --bisect-replay <filename>"),
 	NULL
 };
 
@@ -879,6 +880,93 @@ static int bisect_log(void)
 	return 0;
 }
 
+static int get_next_word(struct strbuf *line, struct strbuf *word)
+{
+	int i;
+	for (i = 0; line->buf[i] != ' ' && line->buf[i] != '\0'; i++)
+		strbuf_addch(word, line->buf[i]);
+
+	return 0;
+}
+
+static int bisect_replay(struct bisect_terms *terms, const char *filename)
+{
+	struct strbuf line = STRBUF_INIT;
+	FILE *fp;
+
+	if (is_empty_or_missing_file(filename))
+		die(_("no such file with name '%s' exists"), filename);
+
+	if (bisect_reset(NULL))
+		return -1;
+
+	fp = fopen(filename, "r");
+
+	while (strbuf_getline(&line, fp) != EOF) {
+		struct strbuf command = STRBUF_INIT;
+		if (starts_with(line.buf, "git bisect ") ||
+		    starts_with(line.buf, "git-bisect "))
+			strbuf_remove(&line, 0, 11);
+		else
+			continue;
+
+		get_terms(terms);
+		get_next_word(&line, &command);
+		if (check_and_set_terms(terms, command.buf)) {
+			strbuf_release(&line);
+			strbuf_release(&command);
+		}
+
+		if (line.buf[command.len] != '\0')
+			strbuf_remove(&line, 0, command.len + 1);
+		else
+			strbuf_remove(&line, 0, command.len);
+
+		if (!strcmp(command.buf, "start")) {
+			struct argv_array argv = ARGV_ARRAY_INIT;
+			sq_dequote_to_argv_array(line.buf, &argv);
+			if (bisect_start(terms, 0, argv.argv, argv.argc)) {
+				strbuf_release(&command);
+				strbuf_release(&line);
+				argv_array_clear(&argv);
+				return -1;
+			}
+			argv_array_clear(&argv);
+			continue;
+		}
+
+		if (one_of(command.buf, terms->term_good.buf,
+		    terms->term_bad.buf, "skip", NULL)) {
+			if (bisect_write(command.buf, line.buf, terms, 0)) {
+				strbuf_release(&command);
+				strbuf_release(&line);
+				return -1;
+			}
+			continue;
+		}
+
+		if (!strcmp(command.buf, "terms")) {
+			struct argv_array argv = ARGV_ARRAY_INIT;
+			sq_dequote_to_argv_array(line. buf, &argv);
+			if (bisect_terms(terms, argv.argv, argv.argc)) {
+				strbuf_release(&command);
+				strbuf_release(&line);
+				argv_array_clear(&argv);
+				return -1;
+			}
+			argv_array_clear(&argv);
+			continue;
+		}
+
+		strbuf_release(&command);
+		strbuf_release(&line);
+		die(_("?? what are you talking about?"));
+	}
+	strbuf_release(&line);
+
+	return bisect_auto_next(terms, NULL);
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -892,7 +980,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_AUTO_NEXT,
 		BISECT_AUTOSTART,
 		BISECT_STATE,
-		BISECT_LOG
+		BISECT_LOG,
+		BISECT_REPLAY
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -918,6 +1007,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("mark the state of ref (or refs)"), BISECT_STATE),
 		OPT_CMDMODE(0, "bisect-log", &cmdmode,
 			 N_("output the contents of BISECT_LOG"), BISECT_LOG),
+		OPT_CMDMODE(0, "bisect-replay", &cmdmode,
+			 N_("replay the bisection process from the given file"), BISECT_REPLAY),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -1001,6 +1092,13 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			die(_("--bisect-log requires 0 arguments"));
 		res = bisect_log();
 		break;
+	case BISECT_REPLAY:
+		if (argc != 1)
+			die(_("--bisect-replay requires 1 argument"));
+		strbuf_addstr(&terms.term_good, "good");
+		strbuf_addstr(&terms.term_bad, "bad");
+		res = bisect_replay(&terms, argv[0]);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index a47e3b5..bf66ee2 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -77,36 +77,6 @@ bisect_visualize() {
 	eval '"$@"' --bisect -- $(cat "$GIT_DIR/BISECT_NAMES")
 }
 
-bisect_replay () {
-	file="$1"
-	test "$#" -eq 1 || die "$(gettext "No logfile given")"
-	test -r "$file" || die "$(eval_gettext "cannot read \$file for replaying")"
-	git bisect--helper --bisect-reset || exit
-	while read git bisect command rev
-	do
-		test "$git $bisect" = "git bisect" || test "$git" = "git-bisect" || continue
-		if test "$git" = "git-bisect"
-		then
-			rev="$command"
-			command="$bisect"
-		fi
-		get_terms
-		git bisect--helper --check-and-set-terms "$command" "$TERM_GOOD" "$TERM_BAD" || exit
-		get_terms
-		case "$command" in
-		start)
-			eval "git bisect--helper --bisect-start $rev" ;;
-		"$TERM_GOOD"|"$TERM_BAD"|skip)
-			git bisect--helper --bisect-write "$command" "$rev" "$TERM_GOOD" "$TERM_BAD" || exit;;
-		terms)
-			git bisect--helper --bisect-terms $rev  || exit;;
-		*)
-			die "$(gettext "?? what are you talking about?")" ;;
-		esac
-	done <"$file"
-	git bisect--helper --bisect-auto-next
-}
-
 bisect_run () {
 	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
 
@@ -201,7 +171,7 @@ case "$#" in
 	reset)
 		git bisect--helper --bisect-reset "$@" ;;
 	replay)
-		bisect_replay "$@" ;;
+		git bisect--helper --bisect-replay "$@" ;;
 	log)
 		git bisect--helper --bisect-log ;;
 	run)

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 11:53

Subject: [PATCH v14 11/27] bisect--helper: `bisect_next_check` & bisect_voc shell function in C
Message-ID: <01020156b73fe6ae-27df9d50-59b2-4ee2-8c5b-89e7e70a2dd0-000000@eu-west-1.amazonses.com>
URL: https://gitlist.dev/e/01020156b73fe6ae-27df9d50-59b2-4ee2-8c5b-89e7e70a2dd0-000000%40eu-west-1.amazonses.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Reimplement `bisect_next_check` shell function in C and add
`bisect-next-check` subcommand to `git bisect--helper` to call it from
git-bisect.sh .

Also reimplement `bisect_voc` shell function in C and call it from
`bisect_next_check` implementation in C.

Using `--bisect-next-check` is a temporary 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 some other methods.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
---
 builtin/bisect--helper.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            |  60 ++-------------------------
 2 files changed, 106 insertions(+), 57 deletions(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 450426c..aca3908 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -6,6 +6,7 @@
 #include "dir.h"
 #include "argv-array.h"
 #include "run-command.h"
+#include "prompt.h"
 
 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
@@ -21,6 +22,7 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-reset [<commit>]"),
 	N_("git bisect--helper --bisect-write <state> <revision> <TERM_GOOD> <TERM_BAD> [<nolog>]"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <TERM_GOOD> <TERM_BAD>"),
+	N_("git bisect--helper --bisect-next-check [<term>] <TERM_GOOD> <TERM_BAD"),
 	NULL
 };
 
@@ -253,6 +255,95 @@ static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
 	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 char *bisect_voc(char *revision_type)
+{
+	if (!strcmp(revision_type, "bad"))
+		return "bad|new";
+	if (!strcmp(revision_type, "good"))
+		return "good|old";
+
+	return NULL;
+}
+
+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.buf);
+	char *good_glob = xstrfmt("%s-*", terms->term_good.buf);
+	char *bad_syn, *good_syn;
+
+	if (ref_exists(bad_ref))
+		missing_bad = 0;
+	free(bad_ref);
+
+	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
+			     (void *) &missing_good);
+	free(good_glob);
+
+	if (!missing_good && !missing_bad)
+		return 0;
+
+	if (!current_term)
+		return -1;
+
+	if (missing_good && !missing_bad && current_term &&
+	    !strcmp(current_term, terms->term_good.buf)) {
+		char *yesno;
+		/*
+		 * have bad (or new) but not good (or old). We could bisect
+		 * although this is less optimum.
+		 */
+		fprintf(stderr, _("Warning: bisecting only with a %s commit\n"),
+			terms->term_bad.buf);
+		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;
+	}
+	bad_syn = xstrdup(bisect_voc("bad"));
+	good_syn = xstrdup(bisect_voc("good"));
+	if (!is_empty_or_missing_file(git_path_bisect_start())) {
+		error(_("You need to give me at least one %s and "
+			"%s revision. You can use \"git bisect %s\" "
+			"and \"git bisect %s\" for that. \n"),
+			bad_syn, good_syn, bad_syn, good_syn);
+		free(bad_syn);
+		free(good_syn);
+		return -1;
+	}
+	else {
+		error(_("You need to start by \"git bisect start\". You "
+			"then need to give me at least one %s and %s "
+			"revision. You can use \"git bisect %s\" and "
+			"\"git bisect %s\" for that.\n"),
+			good_syn, bad_syn, bad_syn, good_syn);
+		free(bad_syn);
+		free(good_syn);
+		return -1;
+	}
+	free(bad_syn);
+	free(good_syn);
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -262,7 +353,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_RESET,
 		CHECK_EXPECTED_REVS,
 		BISECT_WRITE,
-		CHECK_AND_SET_TERMS
+		CHECK_AND_SET_TERMS,
+		BISECT_NEXT_CHECK
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0;
 	struct option options[] = {
@@ -280,6 +372,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 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_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_END()
@@ -330,6 +424,13 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		strbuf_addstr(&terms.term_bad, argv[2]);
 		res = check_and_set_terms(&terms, argv[0]);
 		break;
+	case BISECT_NEXT_CHECK:
+		if (argc != 2 && argc != 3)
+			die(_("--bisect-next-check requires 2 or 3 arguments"));
+		strbuf_addstr(&terms.term_good, argv[0]);
+		strbuf_addstr(&terms.term_bad, argv[1]);
+		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
+		break;
 	default:
 		die("BUG: unknown subcommand '%d'", cmdmode);
 	}
diff --git a/git-bisect.sh b/git-bisect.sh
index bdf2227..fe6c9d0 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -271,59 +271,14 @@ bisect_state() {
 	bisect_auto_next
 }
 
-bisect_next_check() {
-	missing_good= missing_bad=
-	git show-ref -q --verify refs/bisect/$TERM_BAD || missing_bad=t
-	test -n "$(git for-each-ref "refs/bisect/$TERM_GOOD-*")" || missing_good=t
-
-	case "$missing_good,$missing_bad,$1" in
-	,,*)
-		: have both $TERM_GOOD and $TERM_BAD - ok
-		;;
-	*,)
-		# do not have both but not asked to fail - just report.
-		false
-		;;
-	t,,"$TERM_GOOD")
-		# have bad (or new) but not good (or old).  we could bisect although
-		# this is less optimum.
-		eval_gettextln "Warning: bisecting only with a \$TERM_BAD commit." >&2
-		if test -t 0
-		then
-			# TRANSLATORS: Make sure to include [Y] and [n] in your
-			# translation. The program will only accept English input
-			# at this point.
-			gettext "Are you sure [Y/n]? " >&2
-			read yesno
-			case "$yesno" in [Nn]*) exit 1 ;; esac
-		fi
-		: bisect without $TERM_GOOD...
-		;;
-	*)
-		bad_syn=$(bisect_voc bad)
-		good_syn=$(bisect_voc good)
-		if test -s "$GIT_DIR/BISECT_START"
-		then
-
-			eval_gettextln "You need to give me at least one \$bad_syn and one \$good_syn revision.
-(You can use \"git bisect \$bad_syn\" and \"git bisect \$good_syn\" for that.)" >&2
-		else
-			eval_gettextln "You need to start by \"git bisect start\".
-You then need to give me at least one \$good_syn and one \$bad_syn revision.
-(You can use \"git bisect \$bad_syn\" and \"git bisect \$good_syn\" for that.)" >&2
-		fi
-		exit 1 ;;
-	esac
-}
-
 bisect_auto_next() {
-	bisect_next_check && bisect_next || :
+	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD && bisect_next || :
 }
 
 bisect_next() {
 	case "$#" in 0) ;; *) usage ;; esac
 	bisect_autostart
-	bisect_next_check $TERM_GOOD
+	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD $TERM_GOOD|| exit
 
 	# Perform all bisection computation, display and checkout
 	git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
@@ -355,7 +310,7 @@ bisect_next() {
 }
 
 bisect_visualize() {
-	bisect_next_check fail
+	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
 
 	if test $# = 0
 	then
@@ -409,7 +364,7 @@ bisect_replay () {
 }
 
 bisect_run () {
-	bisect_next_check fail
+	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
 
 	while true
 	do
@@ -482,13 +437,6 @@ get_terms () {
 	fi
 }
 
-bisect_voc () {
-	case "$1" in
-	bad) echo "bad|new" ;;
-	good) echo "good|old" ;;
-	esac
-}
-
 bisect_terms () {
 	get_terms
 	if ! test -s "$GIT_DIR/BISECT_TERMS"

--
https://github.com/git/git/pull/287

```

## Pranit Bauva, 2016-08-23 21:24

Subject: Re: [PATCH v14 01/27] bisect--helper: use OPT_CMDMODE instead of OPT_BOOL
Message-ID: <CAFZEwPM6hDbiEVMbe_FakME4h_RNCopyzFcVLsF1PB=V=OheOA@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPM6hDbiEVMbe_FakME4h_RNCopyzFcVLsF1PB%3DV%3DOheOA%40mail.gmail.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Hey everyone,

Sending a "cover letter" to this series.

Changes with wrt v12[1] are:

 * Rebased on v2.10-rc0
 * Two function signatures had changed while the topic
    develop so changed those.
 * Correct the "mark for translation" messages properly as
    I had previously used N_() in some places but I had to
    actually use _().
 * In the patch 04/27[2], bisect_clean_state() is put in bisect.c
   rather than builtin/bisect--helper.c because I will need it
   further when porting bisect_next() function.
 * The patches from 14th are completely new to the series.
    They port even more functions and remove some then unused
    subcommands.
 * 14th patch[3] is a tricky one as it changes a lot of things. I am
    not sure whether to put this all in one patch or split it.

[1]: http://public-inbox.org/git/010201567675adc1-17e27495-6b36-40d1-836d-814da029fcc4-000000@eu-west-1.amazonses.com/
[2]: http://public-inbox.org/git/01020156b73fe66f-bfad6316-39d4-4577-8f75-d1b4b2031263-000000@eu-west-1.amazonses.com/
[3]: http://public-inbox.org/git/01020156b73fe6ce-3b204354-849b-40fd-93ff-2ebcf77df91c-000000@eu-west-1.amazonses.com/

Regards,
Pranit Bauva

```

## Junio C Hamano, 2016-08-23 20:28

Subject: Re: [PATCH v14 01/27] bisect--helper: use OPT_CMDMODE instead of OPT_BOOL
Message-ID: <xmqqmvk3ut4s.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqmvk3ut4s.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe5b4-5dc768ab-b73b-4a21-ab92-018e2a7aa6f7-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> `--next-all` is meant to be used as a subcommand to support multiple
> "operation mode" though the current implementation does not contain any
> other subcommand along side with `--next-all` but further commits will
> include some more subcommands.
>
> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
> Mentored-by: Lars Schneider <larsxschneider@gmail.com>
> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
> ---

A series this size really needs a cover letter that describes what
changes were made relative to the previous round to help reviewers.

I also noticed something curious.  All of your messages are dated

    Date: Tue, 23 Aug 2016 11:53:53 +0000

and I think that is the same as all the previous series, but how are
you sending your patches?  The reason why I ask is because this does
not allow readers to tell their mail reader to sort messages by the
sender's timestamp in order to see the messages in order (as a
matter of fact, git-send-email knows that readers are helped by this
feature, and backdates the first message of 10 patch series by 10
seconds, stamps the second message as later than the first by one
second, etc. to help them).



```

## Pranit Bauva, 2016-08-23 21:07

Subject: Re: [PATCH v14 01/27] bisect--helper: use OPT_CMDMODE instead of OPT_BOOL
Message-ID: <CAFZEwPPUasJvZO=LHOzu85FwPAsg-OQo57wQckXJdiHTP4_34A@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPPUasJvZO%3DLHOzu85FwPAsg-OQo57wQckXJdiHTP4_34A%40mail.gmail.com
In-Reply-To: <xmqqmvk3ut4s.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Wed, Aug 24, 2016 at 1:58 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> `--next-all` is meant to be used as a subcommand to support multiple
>> "operation mode" though the current implementation does not contain any
>> other subcommand along side with `--next-all` but further commits will
>> include some more subcommands.
>>
>> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
>> Mentored-by: Lars Schneider <larsxschneider@gmail.com>
>> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
>> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
>> ---
>
> A series this size really needs a cover letter that describes what
> changes were made relative to the previous round to help reviewers.

I am actually using SubmitGit these days as I am back in my campus and
IMAP/SMTP connections are blocked here. SubmitGit doesn't have the
option to include a cover letter. Though I can describe the changes by
including a separate email as a reply to 1st patch. I will send the
changes according to v12 since v13 wasn't commented on.

> I also noticed something curious.  All of your messages are dated
>
>     Date: Tue, 23 Aug 2016 11:53:53 +0000
>
> and I think that is the same as all the previous series, but how are
> you sending your patches?  The reason why I ask is because this does
> not allow readers to tell their mail reader to sort messages by the
> sender's timestamp in order to see the messages in order (as a
> matter of fact, git-send-email knows that readers are helped by this
> feature, and backdates the first message of 10 patch series by 10
> seconds, stamps the second message as later than the first by one
> second, etc. to help them).

This might be a bug in SubmitGit. I didn't notice this previously.

Regards,
Pranit Bauva

```

## Junio C Hamano, 2016-08-24 20:58

Subject: Re: [PATCH v14 04/27] bisect--helper: `bisect_clean_state` shell function in C
Message-ID: <xmqqd1kxq3yj.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqd1kxq3yj.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe66f-bfad6316-39d4-4577-8f75-d1b4b2031263-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> 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>
> ---

This seems to be where this round diverges from the previous one.
This patch in this round has more stuff that used to be in
builtin/bisect--helper.c in the previous one in bisect.c.  Because I
am not sure if the distinction would make that much of a difference
(after all, I do not think of a good reason why many bisect internals
need to be exposed to anything other than the eventual builtin/bisect.c
that retires git-bisect.sh), I am OK with the change to this patch
between the previous round and this round.


```

## Junio C Hamano, 2016-08-24 21:12

Subject: Re: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <xmqq4m69q3b2.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq4m69q3b2.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe69a-13136cfb-4daa-4f5d-9b56-537adf2c6942-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +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) {

Hmm, tricky but correct to do the "< 1" comparison.  If the file
does not exist, you'd get -1; if it fails to read it, you'd get -1;
if it turns out to be empty, you'd get 0.

> +			printf("We are not bisecting.\n");
> +			return 0;
> +		}
> +		strbuf_rtrim(&branch);
> +	} else {
> +		struct object_id oid;
> +		if (get_oid(commit, &oid))
> +			return error(_("'%s' is not a valid commit"), commit);

The original is

	rev-parse --quiet --verify "$1^{commit}"

Unless the caller of this function already appended "^{commit}" to
whatever the user gave "bisect--helper bisect-reset", this
conversion is not equivalent.  If you said

    git bisect reset HEAD:

get_oid() would tell you that the top-level tree object of the
current commit exists in the object store, but the original is
meant to catch "That's not a commit, it's a tree!" before attempting
to run "git checkout" on it.

I think get_sha1_committish() is what you want to use here.

> +		strbuf_addstr(&branch, commit);
> +	}

Also this version fails to catch "bisect reset a b c" as an error, I
suspect.

> @@ -627,7 +603,7 @@ case "$#" in
>  	visualize|view)
>  		bisect_visualize "$@" ;;
>  	reset)
> -		bisect_reset "$@" ;;
> +		git bisect--helper --bisect-reset "$@" ;;
>  	replay)
>  		bisect_replay "$@" ;;
>  	log)
>
> --
> https://github.com/git/git/pull/287

```

## Junio C Hamano, 2016-08-24 22:13

Subject: Re: [PATCH v14 08/27] bisect--helper: `is_expected_rev` & `check_expected_revs` shell function in C
Message-ID: <xmqqlgzlolwa.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqlgzlolwa.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe69f-6b734e3c-806c-431d-aa52-c96b3783f248-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +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) >= 0) {
> +		strbuf_trim(&actual_hex);
> +		res = !strcmp(actual_hex.buf, expected_hex);

If it is known to have 40-hex:

 (1) accepting ">= 0" seems way too lenient.  You only expect a
     41-byte file (or 42 if somebody would write CRLF, but I do not
     think anybody other than yourself is expected to write into
     this file, and you do not write CRLF yourself);

 (2) strbuf_trim() is overly loose.  You only want to trim the
     terimnating LF and it is an error to have other trailing
     whitespaces.

I think the latter is not a new problem and it is OK to leave it
as-is; limiting (1) to >= 40 may still be a good change, though,
because it makes the intention of the code clearer.


```

## Junio C Hamano, 2016-08-24 22:40

Subject: Re: [PATCH v14 11/27] bisect--helper: `bisect_next_check` & bisect_voc shell function in C
Message-ID: <xmqqbn0hoko0.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqbn0hoko0.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6ae-27df9d50-59b2-4ee2-8c5b-89e7e70a2dd0-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +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 char *bisect_voc(char *revision_type)
> +{
> +	if (!strcmp(revision_type, "bad"))
> +		return "bad|new";
> +	if (!strcmp(revision_type, "good"))
> +		return "good|old";
> +
> +	return NULL;
> +}
> +
> +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.buf);
> +	char *good_glob = xstrfmt("%s-*", terms->term_good.buf);
> +	char *bad_syn, *good_syn;
> +
> +	if (ref_exists(bad_ref))
> +		missing_bad = 0;
> +	free(bad_ref);
> +
> +	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
> +			     (void *) &missing_good);
> +	free(good_glob);
> +
> +	if (!missing_good && !missing_bad)
> +		return 0;
> +
> +	if (!current_term)
> +		return -1;
> +
> +	if (missing_good && !missing_bad && current_term &&
> +	    !strcmp(current_term, terms->term_good.buf)) {
> +		char *yesno;
> +		/*
> +		 * have bad (or new) but not good (or old). We could bisect
> +		 * although this is less optimum.
> +		 */
> +		fprintf(stderr, _("Warning: bisecting only with a %s commit\n"),
> +			terms->term_bad.buf);
> +		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;
> +	}
> +	bad_syn = xstrdup(bisect_voc("bad"));
> +	good_syn = xstrdup(bisect_voc("good"));
> +	if (!is_empty_or_missing_file(git_path_bisect_start())) {
> +		error(_("You need to give me at least one %s and "
> +			"%s revision. You can use \"git bisect %s\" "
> +			"and \"git bisect %s\" for that. \n"),
> +			bad_syn, good_syn, bad_syn, good_syn);
> +		free(bad_syn);
> +		free(good_syn);
> +		return -1;
> +	}
> +	else {
> +		error(_("You need to start by \"git bisect start\". You "
> +			"then need to give me at least one %s and %s "
> +			"revision. You can use \"git bisect %s\" and "
> +			"\"git bisect %s\" for that.\n"),
> +			good_syn, bad_syn, bad_syn, good_syn);
> +		free(bad_syn);
> +		free(good_syn);
> +		return -1;
> +	}
> +	free(bad_syn);
> +	free(good_syn);
> +
> +	return 0;

This one looks OK, but I think the same "Wouldn't it become cleaner
to have a 'finish:' label at the end and jump there?" comment
applies to this implementation, too.


```

## Junio C Hamano, 2016-08-24 22:30

Subject: Re: [PATCH v14 09/27] bisect--helper: `bisect_write` shell function in C
Message-ID: <xmqqfuptol4h.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqfuptol4h.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6a7-2e9df745-e3f4-4830-a1af-4acae7964c11-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +struct bisect_terms {
> +	struct strbuf term_good;
> +	struct strbuf term_bad;
> +};

I think "struct strbuf" is overrated.  For things like this, where
these fields will never change once it is set (and setting it is
done atomically, not incrementally), there is no good reason to use
define the fields as strbuf.

Only because you chose to use strbuf for these two fields, you have
to make unnecessarily copies of argv[] in the command parser, and
you have to remember to discard these copies later.

I think you can just say "const char *" in this case.  

> +static int bisect_write(const char *state, const char *rev,
> +			const struct bisect_terms *terms, int nolog)
> +{
> +	struct strbuf tag = STRBUF_INIT;
> +	struct strbuf commit_name = STRBUF_INIT;
> +	struct object_id oid;
> +	struct commit *commit;
> +	struct pretty_print_context pp = {0};
> +	FILE *fp;
> +
> +	if (!strcmp(state, terms->term_bad.buf))
> +		strbuf_addf(&tag, "refs/bisect/%s", state);
> +	else if (one_of(state, terms->term_good.buf, "skip", NULL))
> +		strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
> +	else
> +		return error(_("Bad bisect_write argument: %s"), state);

OK.

> +	if (get_oid(rev, &oid)) {
> +		strbuf_release(&tag);
> +		return error(_("couldn't get the oid of the rev '%s'"), rev);
> +	}
> +
> +	if (update_ref(NULL, tag.buf, oid.hash, NULL, 0,
> +		       UPDATE_REFS_MSG_ON_ERR)) {
> +		strbuf_release(&tag);
> +		return -1;
> +	}
> +	strbuf_release(&tag);
> +
> +	fp = fopen(git_path_bisect_log(), "a");
> +	if (!fp)
> +		return error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
> +
> +	commit = lookup_commit_reference(oid.hash);
> +	format_commit_message(commit, "%s", &commit_name, &pp);
> +	fprintf(fp, "# %s: [%s] %s\n", state, sha1_to_hex(oid.hash),
> +		commit_name.buf);
> +	strbuf_release(&commit_name);
> +
> +	if (!nolog)
> +		fprintf(fp, "git bisect %s %s\n", state, rev);
> +
> +	fclose(fp);
> +	return 0;

You seem to be _release()ing tag all over the place.

Would it make sense to have a single clean-up label at the end of
function, introduce a "int retval" variable and set it to -1 (or
whatever) when an error is detected and "goto" to the label?  It may
make it harder to make such a leak.  That is, to end the function
more like:

	finish:
        	if (fp)
                	fclose(fp);
		strbuf_release(&tag);
                strbuf_release(&commit_name);
		return retval;
	}

and have sites with potential errors do something like this:

	if (update_ref(...)) {
        	retval = -1;
                goto finish;
	}

> +	struct bisect_terms terms;
> +	bisect_terms_init(&terms);

With the type of "struct bisect_terms" members corrected, you do not
even need the _init() function.

> @@ -182,24 +251,38 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
>  		usage_with_options(git_bisect_helper_usage, options);
>  
>  	switch (cmdmode) {
> +	int nolog;
>  	case NEXT_ALL:
>  		return bisect_next_all(prefix, no_checkout);
>  	case WRITE_TERMS:
>  		if (argc != 2)
>  			die(_("--write-terms requires two arguments"));
> -		return write_terms(argv[0], argv[1]);
> +		res = write_terms(argv[0], argv[1]);
> +		break;
>  	case BISECT_CLEAN_STATE:
>  		if (argc != 0)
>  			die(_("--bisect-clean-state requires no arguments"));
> -		return bisect_clean_state();
> +		res = bisect_clean_state();
> +		break;
>  	case BISECT_RESET:
>  		if (argc > 1)
>  			die(_("--bisect-reset requires either zero or one arguments"));
> -		return bisect_reset(argc ? argv[0] : NULL);
> +		res = bisect_reset(argc ? argv[0] : NULL);
> +		break;
>  	case CHECK_EXPECTED_REVS:
> -		return check_expected_revs(argv, argc);
> +		res = check_expected_revs(argv, argc);
> +		break;
> +	case BISECT_WRITE:
> +		if (argc != 4 && argc != 5)
> +			die(_("--bisect-write requires either 4 or 5 arguments"));
> +		nolog = (argc == 5) && !strcmp(argv[4], "nolog");
> +		strbuf_addstr(&terms.term_good, argv[2]);
> +		strbuf_addstr(&terms.term_bad, argv[3]);

Here,

	terms.term_good = argv[2];
	terms.term_bad = argv[3];

and then you do not need bisect_terms_release() at all.

> +		res = bisect_write(argv[0], argv[1], &terms, nolog);
> +		break;
>  	default:
>  		die("BUG: unknown subcommand '%d'", cmdmode);
>  	}
> -	return 0;
> +	bisect_terms_release(&terms);
> +	return res;
>  }

```

## Junio C Hamano, 2016-08-25 18:05

Subject: Re: [PATCH v14 12/27] bisect--helper: `get_terms` & `bisect_terms` shell function in C
Message-ID: <xmqqmvk0n2pl.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqmvk0n2pl.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6b3-3ccd9de5-604d-4e7d-919d-a3adae869ebf-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
> +{
> +	int i;
> +
> +	if (get_terms(terms)) {
> +		fprintf(stderr, _("no terms defined\n"));
> +		return -1;
> +	}
> +	if (argc == 0) {
> +		printf(_("Your current terms are %s for the old state\nand "
> +		       "%s for the new state.\n"), terms->term_good.buf,
> +		       terms->term_bad.buf);
> +		return 0;
> +	}
> +
> +	for (i = 0; i < argc; i++) {
> +		if (!strcmp(argv[i], "--term-good"))
> +			printf("%s\n", terms->term_good.buf);
> +		else if (!strcmp(argv[i], "--term-bad"))
> +			printf("%s\n", terms->term_bad.buf);
> +		else
> +			printf(_("invalid argument %s for 'git bisect "
> +				  "terms'.\nSupported options are: "
> +				  "--term-good|--term-old and "
> +				  "--term-bad|--term-new."), argv[i]);
> +	}

The original took only one and gave one answer (and errored out when
the user asked for more), but this one loops.  I can see either way
is OK and do not think of a good reason to favor one over the other;
unless there is a strong reason why you need this extended behaviour
that allows users to ask multiple questions, I'd say we should keep
the original behaviour.


```

## Junio C Hamano, 2016-08-25 19:02

Subject: Re: [PATCH v14 13/27] bisect--helper: `bisect_start` shell function partially in C
Message-ID: <xmqqd1kwn035.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqd1kwn035.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6b9-5e500c96-9bc3-4a6b-beb9-b5988dc9ee85-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +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;
> +	struct string_list revs = STRING_LIST_INIT_DUP;
> +	struct string_list states = STRING_LIST_INIT_DUP;

The original has a single state, not states.  Let's see if there is
a reason behind the name change....

> +	unsigned char sha1[20];
> +	struct object_id oid;

More on these below...

> + ...
> +	for (i = 0; i < argc; i++) {
> +		const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
> +		if (!strcmp(argv[i], "--")) {
> +			has_double_dash = 1;
> +			break;
> +		} else if (!strcmp(argv[i], "--no-checkout"))
> +			no_checkout = 1;
> +		else if (!strcmp(argv[i], "--term-good") ||
> + ...
> +		} else if (starts_with(argv[i], "--") &&
> +			 !one_of(argv[i], "--term-good", "--term-bad", NULL)) {
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			die(_("unrecognised option: '%s'"), argv[i]);
> +		} else if (get_oid(commit_id, &oid) && has_double_dash) {
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			die(_("'%s' does not appear to be a valid revision"), argv[i]);
> +		} else {
> +			string_list_append(&revs, oid_to_hex(&oid));
> +		}
> +	}

What I do not understand is clearing the string list "states" inside
this loop.  It may have been INIT_DUPed, but nothing in this loop
adds anything to it.  Because "revs" does get extended in the loop,
it is understandable if you wanted to clear it before dying, but "if
you are dying anyway why bother clearing?" is also a valid stance to
take.

The same "perhaps want to use the 'retval' with goto 'finish:' pattern?"
comment applies here, too.

> +	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.
> +	 */
> +	must_write_terms |= !!revs.nr;
> +	for (i = 0; i < revs.nr; i++) {
> +		if (bad_seen)
> +			string_list_append(&states, terms->term_good.buf);
> +		else {
> +			bad_seen = 1;
> +			string_list_append(&states, terms->term_bad.buf);
> +		}
> +	}

This is certainly different from the original.  We used to do one
"bisect_write" per element in revs in the loop; we no longer do that
and instead collect them in states list.  Each element in these two
lists, i.e. revs.item[i] and states.item[i], corresponds to each
other.

That explains why the variable is renamed to states.  We haven't
seen enough to say if this behaviour change is a good idea or not.

> +	/*
> +	 * Verify HEAD
> +	 */
> +	head = resolve_ref_unsafe("HEAD", 0, sha1, &flags);
> +	if (!head) {
> +		if (get_sha1("HEAD", sha1)) {
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			die(_("Bad HEAD - I need a HEAD"));
> +		}
> +	}
> +	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)) {
> +				error(_("checking out '%s' failed. Try 'git "
> +					"bisect start <valid-branch>'."),
> +				      start_head.buf);
> +				strbuf_release(&start_head);
> +				string_list_clear(&revs, 0);
> +				string_list_clear(&states, 0);
> +				return -1;

The original died here, but you expect the caller to respond to a
negative return.  I haven't read enough to judge if that is a good
idea, but doesn't it make sense to do the same throughout the
function consistently?  I saw a few die()'s already in the command
line parsing loop--shouldn't they also return -1?

The original has called bisect_write already when we attempt this
checkout and the user will see the states in the filesystem.  This
rewrite does not.  What effect does this behaviour change have to
the end-user experience?  The error message tells the end user to
run another "git bisect start" with a valid commit, and when that
happens, hopefully she will give us something we can check out, and
then we will hit the bisect_clean_state() call we see below before
starting to do anything meaningful, so I am guessing it won't, but
I just want to make sure that you thought about the ramifications
of the change above to delay calls to bisect_write.

> +			}
> +		}
> +	} else {
> +		if (starts_with(head, "refs/heads/") ||
> +		    !get_oid_hex(head, &oid) || ref_exists(head)) {

This ref_exists() check is new, and I think it should not be there.
In the original, if .git/HEAD pointed at refs/tags/v1.0, we would
have diagnosed it as a strange symbolic ref.  This no longer does.

If you wanted to make sure that the branch exists, it should have
been

	if ((starts_with(head, "refs/heads/") && ref_exists(head)) ||
	    !get_oid_hex(head, &oid)) {

anyway.

Also, why do you use get_oid_hex() here?  You used get_sha1("HEAD",
sha1) in the early part of "Verify HEAD" above, which seems to be
perfectly adequate.  That sha1 taken from get_sha1() is what you end
up using in the code below anyway.  If you can stick to one or the
other, please do so.

> +			/*
> +			 * 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())) {
> +				strbuf_release(&start_head);
> +				string_list_clear(&revs, 0);
> +				string_list_clear(&states, 0);
> +				die(_("won't bisect on cg-seek'ed tree"));
> +			}

Not to be done as part of this series, but it probably is safe to
retire this part by now.  Cogito has been dead for how many years?

> +			if (starts_with(head, "refs/heads/")) {
> +				strbuf_reset(&start_head);
> +				strbuf_addstr(&start_head, head + 11);

skip_prefix?

> +			}
> +			else {
> +				strbuf_reset(&start_head);
> +				strbuf_addstr(&start_head, sha1_to_hex(sha1));
> +			}
> +		} else {
> +			strbuf_release(&start_head);
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			die(_("Bad HEAD - strange symbolic ref"));
> +		}
> +	}

I wonder the whole thing above is better restructured to avoid
repeated checks of the same thing.

	if (is it 40-hex, i.e. detached?) {
		stuff it to start_head;
	} else if (skip_prefix(head, "refs/heads/", &branchname)) {
        	do the "cogito" check;
                stuff it to start_head;
	} else {
        	that's a strange symbolic ref HEAD you have there;
	}

> +	/*
> +	 * Get rid of any old bisect state.
> +	 */
> +	if (bisect_clean_state()) {
> +		return -1;
> +	}

If we are going to get a lot more code inside {} in later patches,
then this single "return -1" enclosed inside a {} pair is
justifiable (but in that case we'd prefer an empty line after it to
separate it from the next comment block).  Otherwise lose the {}.

> +	/*
> +	 * 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".
> +	 */

That explains the "trap" statements in the original.  Does it apply
to this code here?

> +	/*
> +	 * Write new start state
> +	 */
> +	write_file(git_path_bisect_start(), "%s\n", start_head.buf);
> +
> +	if (no_checkout) {
> +		get_oid(start_head.buf, &oid);
> +		if (update_ref(NULL, "BISECT_HEAD", oid.hash, NULL, 0,
> +			       UPDATE_REFS_MSG_ON_ERR)) {
> +			strbuf_release(&start_head);
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			return -1;
> +		}
> +	}
> +	strbuf_release(&start_head);
> +
> +	if (pathspec_pos < argc - 1)
> +		sq_quote_argv(&bisect_names, argv + pathspec_pos, 0);
> +	write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
> +	strbuf_release(&bisect_names);
> +
> +	for (i = 0; i < states.nr; i++) {
> +		if (bisect_write(states.items[i].string,
> +				  revs.items[i].string, terms, 1)) {
> +			string_list_clear(&revs, 0);
> +			string_list_clear(&states, 0);
> +			return -1;
> +		}
> +	}

Hmph.  I do not particuarly see why doing this in a separate loop
here, instead of doing it just like in the original, i.e. inside the
loop we already saw, is an improvement.  It seems to me that the
only effect of this change is to make the code more complex by
forcing you to maintain (and clear) another string list "states" and
have a separate loop here.

Unless there is a reason why delaying calls to bisect_write() is a
good thing and I am not seeing it, that is.

> diff --git a/git-bisect.sh b/git-bisect.sh
> index d6c8b5a..f0896b3 100755
> --- a/git-bisect.sh
> +++ b/git-bisect.sh
> @@ -71,122 +71,7 @@ bisect_autostart() {
>  }
>  
>  bisect_start() {
> -...
> +	git bisect--helper --bisect-start $@ || exit
>  ...
> +	get_terms

Understandable.  As the handling of the terms is done in the helper,
you need to read the terms it left in the filesystem.  OK.

>  	bisect_auto_next


```

## Junio C Hamano, 2016-08-25 19:43

Subject: Re: [PATCH v14 13/27] bisect--helper: `bisect_start` shell function partially in C
Message-ID: <xmqq8tvkmy7b.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq8tvkmy7b.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <xmqqd1kwn035.fsf@gitster.mtv.corp.google.com>

```
Junio C Hamano <gitster@pobox.com> writes:

>> +	for (i = 0; i < revs.nr; i++) {
>> +		if (bad_seen)
>> +			string_list_append(&states, terms->term_good.buf);
>> +		else {
>> +			bad_seen = 1;
>> +			string_list_append(&states, terms->term_bad.buf);
>> +		}
>> +	}
>
> This is certainly different from the original.  We used to do one
> "bisect_write" per element in revs in the loop; we no longer do that
> and instead collect them in states list.  Each element in these two
> lists, i.e. revs.item[i] and states.item[i], corresponds to each
> other.
>
> That explains why the variable is renamed to states.  We haven't
> seen enough to say if this behaviour change is a good idea or not.

Ahh, I misread the original.  It accumulates the writes to be
executed in $eval and does so at the end.  So there is no change in
behaviour.

So please ignore that point in the previous message.  That leaves
only the following points:

 * Perhaps 'retval' with 'goto finish' pattern?

 * ref_exists()?  Perhaps use skip_prefix(head, "refs/heads/, &branch)?

 * if (clean-state) { return -1 }?

 * Is comment on trap relevant here?

Sorry, and thanks.

```

## Junio C Hamano, 2016-08-25 20:30

Subject: Re: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <xmqq37lsmw15.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq37lsmw15.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6ce-3b204354-849b-40fd-93ff-2ebcf77df91c-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> A lot of parts of bisect.c uses exit() and these signals are then
> trapped in the `bisect_start` function. Since the shell script ceases
> its existence it would be necessary to convert those exit() calls to
> return statements so that errors can be reported efficiently in C code.

Is efficiency really an issue?  I think the real reason is that it
would make it impossible for the callers to handle errors, if you do
not convert and let the error codepaths exit().

> @@ -729,7 +735,7 @@ static struct commit **get_bad_and_good_commits(int *rev_nr)
>  	return rev;
>  }
>  
> -static void handle_bad_merge_base(void)
> +static int handle_bad_merge_base(void)
>  {
>  	if (is_expected_rev(current_bad_oid)) {
>  		char *bad_hex = oid_to_hex(current_bad_oid);
> @@ -750,17 +756,18 @@ static void handle_bad_merge_base(void)
>  				"between %s and [%s].\n"),
>  				bad_hex, term_bad, term_good, bad_hex, good_hex);
>  		}
> -		exit(3);
> +		return 3;
>  	}
>  
>  	fprintf(stderr, _("Some %s revs are not ancestor of the %s rev.\n"
>  		"git bisect cannot work properly in this case.\n"
>  		"Maybe you mistook %s and %s revs?\n"),
>  		term_good, term_bad, term_good, term_bad);
> -	exit(1);
> +	bisect_clean_state();
> +	return 1;

What is the logic behind this function sometimes clean the state,
and some other times do not, when it makes an error-return?  We see
above that "return 3" codepath leaves the state behind.

Either you forgot a necessary clean_state in "return 3" codepath,
or you forgot to document why the distinction exists in the in-code
comment for the function.  I cannot tell which, but I am leaning
towards guessing that it is the former.

> -static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
> +static int check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
>  {
>  	char *filename = git_pathdup("BISECT_ANCESTORS_OK");
>  	struct stat st;
> -	int fd;
> +	int fd, res = 0;
>  
>  	if (!current_bad_oid)
>  		die(_("a %s revision is needed"), term_bad);

Can you let it die yere?

> @@ -873,8 +890,11 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
>  			      filename);
>  	else
>  		close(fd);
> +
> +	return 0;
>   done:
>  	free(filename);
> +	return 0;
>  }

Who owns "filename"?  The first "return 0" leaves it unfreed, and
when "goto done" is done, it is freed.

The above two may indicate that "perhaps 'retval + goto finish'
pattern?" is a really relevant suggestion for the earlier steps in
this series.

>  	if (!all) {
>  		fprintf(stderr, _("No testable commit found.\n"
>  			"Maybe you started with bad path parameters?\n"));
> -		exit(4);
> +		return 4;
>  	}
>  
>  	bisect_rev = revs.commits->item->object.oid.hash;
>  
>  	if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
> -		exit_if_skipped_commits(tried, current_bad_oid);
> +		res = exit_if_skipped_commits(tried, current_bad_oid);
> +		if (res)
> +			return res;
> +
>  		printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),
>  			term_bad);
>  		show_diff_tree(prefix, revs.commits->item);
>  		/* This means the bisection process succeeded. */
> -		exit(10);
> +		return 10;
>  	}
>  
>  	nr = all - reaches - 1;
> @@ -1005,7 +1033,11 @@ int bisect_next_all(const char *prefix, int no_checkout)
>  		  "Bisecting: %d revisions left to test after this %s\n",
>  		  nr), nr, steps_msg);
>  
> -	return bisect_checkout(bisect_rev, no_checkout);
> +	res = bisect_checkout(bisect_rev, no_checkout);
> +	if (res)
> +		bisect_clean_state();
> +
> +	return res;
>  }

There were tons of "exit_if" that was converted to "if (res) return
res" above, instead of jumping here to cause clean_state to be
called.  I cannot tell if this new call to clean_state() is wrong,
or all the earlier "return res" should come here.  I am guessing the
latter.

> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
> index c64996a..ef7b3a1 100644
> --- a/builtin/bisect--helper.c
> +++ b/builtin/bisect--helper.c
> @@ -8,6 +8,7 @@
>  #include "run-command.h"
>  #include "prompt.h"
>  #include "quote.h"
> +#include "revision.h"
>  
>  static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
>  static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
> @@ -29,6 +30,8 @@ static const char * const git_bisect_helper_usage[] = {
>  	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>...]"),
> +	N_("git bisect--helper --bisect-next"),
> +	N_("git bisect--helper --bisect-auto-next"),
>  	NULL
>  };
>  
> @@ -396,6 +399,129 @@ static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
>  	return 0;
>  }
>  
> +static int register_good_ref(const char *refname,
> +			     const struct object_id *oid, int flags,
> +			     void *cb_data)
> +{
> +	struct string_list *good_refs = cb_data;
> +	string_list_append(good_refs, oid_to_hex(oid));
> +	return 0;
> +}
> +
> +static int bisect_next(struct bisect_terms *terms, const char *prefix)
> +{
> +	int res, no_checkout;
> +
> +	/* In case of mistaken revs or checkout error, or signals received,

That's an unbalanced comment.  You end the block with "*/" on its
own line, so you should start the block with "/*" on its own line.
There seems to be at least one more such comment in this patch but I
won't repeat.

> +	 * "bisect_auto_next" below may exit or misbehave.
> +	 * We have to trap this to be able to clean up using
> +	 * "bisect_clean_state".
> +	 */

"exit" meaning "call exit() to terminate the process", or something
else?  If the latter, don't say "exit", but say "return error".

> +	if (bisect_next_check(terms, terms->term_good.buf))
> +		return -1;

Mental note.  The "autostart" in the original is gone.  Perhaps it
is done by next_check in this code, but we haven't seen that yet.

> +	no_checkout = !is_empty_or_missing_file(git_path_bisect_head());
> +
> +	/* Perform all bisection computation, display and checkout */
> +	res = bisect_next_all(prefix , no_checkout);
> +
> +	if (res == 10) {
> +		FILE *fp;
> +		unsigned char sha1[20];
> +		struct commit *commit;
> +		struct pretty_print_context pp = {0};
> +		struct strbuf commit_name = STRBUF_INIT;
> +		char *bad_ref = xstrfmt("refs/bisect/%s",
> +					      terms->term_bad.buf);
> +		read_ref(bad_ref, sha1);
> +		commit = lookup_commit_reference(sha1);
> +		format_commit_message(commit, "%s", &commit_name, &pp);
> +		fp = fopen(git_path_bisect_log(), "a");
> +		if (!fp) {
> +			free(bad_ref);
> +			strbuf_release(&commit_name);
> +			return -1;
> +		}
> +		if (fprintf(fp, "# first %s commit: [%s] %s\n",
> +			    terms->term_bad.buf, sha1_to_hex(sha1),
> +			    commit_name.buf) < 1){
> +			free(bad_ref);
> +			strbuf_release(&commit_name);
> +			fclose(fp);
> +			return -1;
> +		}
> +		free(bad_ref);
> +		strbuf_release(&commit_name);
> +		fclose(fp);
> +		return 0;

Doesn't it bother you that you have to write free(bad_ref)...fclose(fp)
repeatedly?

> +	}
> +	else if (res == 2) {
> +		FILE *fp;
> +		struct rev_info revs;
> +		struct argv_array rev_argv = ARGV_ARRAY_INIT;
> +		struct string_list good_revs = STRING_LIST_INIT_DUP;
> +		struct pretty_print_context pp = {0};
> +		struct commit *commit;
> +		char *term_good = xstrfmt("%s-*", terms->term_good.buf);
> +		int i;
> +
> +		fp = fopen(git_path_bisect_log(), "a");
> +		if (!fp) {
> +			free(term_good);
> +			return -1;
> +		}
> +		if (fprintf(fp, "# only skipped commits left to test\n") < 1) {
> +			free(term_good);
> +			fclose(fp);
> +			return -1;
> +		}
> +		for_each_glob_ref_in(register_good_ref, term_good,
> +				     "refs/bisect/", (void *) &good_revs);
> +
> +		free(term_good);

Doesn't it bother you that you have to write free(term_good) repeatedly?

> +		argv_array_pushl(&rev_argv, "skipped_commits", "refs/bisect/bad", "--not", NULL);
> +		for (i = 0; i < good_revs.nr; i++)
> +			argv_array_push(&rev_argv, good_revs.items[i].string);
> +
> +		/* It is important to reset the flags used by revision walks
> +		 * as the previous call to bisect_next_all() in turn
> +		 * setups a revision walk.
> +		 */
> +		reset_revision_walk();
> +		init_revisions(&revs, NULL);
> +		rev_argv.argc = setup_revisions(rev_argv.argc, rev_argv.argv, &revs, NULL);
> +		argv_array_clear(&rev_argv);
> +		string_list_clear(&good_revs, 0);

Are you sure that the revision walking machinery is prepared to see
the argv[] and elements in it you have given to setup_revisions()
gets cleared before it starts doing the real work in
prepare_revision_walk()?  I am reasonably sure that the machinery
borrows strings like pathspec elements from the caller and expects
them to stay during revision traversal.

You seem to have acquired a habit of freeing and clearing things
early, which is bad.  Instead, make it a habit of free/clear at the
end, and make sure all error paths go through that central freeing
site.  That tends to future-proof your code better from leaking even
when later other people change it.

> +		if (prepare_revision_walk(&revs)) {
> +			die(_("revision walk setup failed\n"));
> +		}

This one is still allowed to die, without clean_state?

> +		while ((commit = get_revision(&revs)) != NULL) {
> +			struct strbuf commit_name = STRBUF_INIT;
> +			format_commit_message(commit, "%s",
> +					      &commit_name, &pp);
> +			fprintf(fp, "# possible first %s commit: "
> +				    "[%s] %s\n", terms->term_bad.buf,
> +				    oid_to_hex(&commit->object.oid),
> +				    commit_name.buf);
> +			strbuf_release(&commit_name);
> +		}
> +
> +		fclose(fp);
> +		return res;
> +	}
> +
> +	return res;
> +}

> @@ -415,47 +541,67 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
>  		no_checkout = 1;
>  
>  	for (i = 0; i < argc; i++) {
> -		if (!strcmp(argv[i], "--")) {
> +		const char *arg;
> +		if (starts_with(argv[i], "'"))
> +			arg = sq_dequote(xstrdup(argv[i]));
> +		else
> +			arg = argv[i];
> +		if (!strcmp(arg, "--")) {
>  			has_double_dash = 1;
>  			break;
>  		}
>  	}

This is really bad; you are blindly assuming that anything that
begins with "'" begins with "'" because "git-bisect.sh" sq-quoted
and it never directly came from the command line that _wanted_ to
give you something that begins with a "'".

I suspect that you should be able to dequote on the calling script
side.  Then all these ugliness would disappear.

>  	for (i = 0; i < argc; i++) {
> -		const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
> +		const char *arg, *commit_id;
> +		if (starts_with(argv[i], "'"))
> +			arg = sq_dequote(xstrdup(argv[i]));
> +		else
> +			arg = argv[i];

Likewise.

> +		commit_id = xstrfmt("%s^{commit}", arg);

In any case, I think a separate "const char *arg" that is an alias
to argv[i] in the loop is a very good idea to do from the very
beginning (i.e. should be done in a much much earlier patch in this
series).

```

## Pranit Bauva, 2016-08-26 13:46

Subject: Re: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <CAFZEwPPfXvLUtcBR6cYAP2dT8FAePFPjDSnVm8BhpLN9cfR1uw@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPPfXvLUtcBR6cYAP2dT8FAePFPjDSnVm8BhpLN9cfR1uw%40mail.gmail.com
In-Reply-To: <xmqq4m69q3b2.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Thu, Aug 25, 2016 at 2:42 AM, Junio C Hamano <gitster@pobox.com> wrote:
>
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
> > +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) {
>
> Hmm, tricky but correct to do the "< 1" comparison.  If the file
> does not exist, you'd get -1; if it fails to read it, you'd get -1;
> if it turns out to be empty, you'd get 0.
>
> > +                     printf("We are not bisecting.\n");
> > +                     return 0;
> > +             }
> > +             strbuf_rtrim(&branch);
> > +     } else {
> > +             struct object_id oid;
> > +             if (get_oid(commit, &oid))
> > +                     return error(_("'%s' is not a valid commit"), commit);
>
> The original is
>
>         rev-parse --quiet --verify "$1^{commit}"
>
> Unless the caller of this function already appended "^{commit}" to
> whatever the user gave "bisect--helper bisect-reset", this
> conversion is not equivalent.  If you said
>
>     git bisect reset HEAD:
>
> get_oid() would tell you that the top-level tree object of the
> current commit exists in the object store, but the original is
> meant to catch "That's not a commit, it's a tree!" before attempting
> to run "git checkout" on it.
>
> I think get_sha1_committish() is what you want to use here.
>
> > +             strbuf_addstr(&branch, commit);
> > +     }
>

Ya! get_sha1_committish() would be better. Thanks!

>
> Also this version fails to catch "bisect reset a b c" as an error, I
> suspect.

It didn't when I tried it right now. Could you please elaborate on why
you think it can fail? There might be a thing which I haven't tested.

Regards,
Pranit Bauva

```

## Junio C Hamano, 2016-08-26 16:29

Subject: Re: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <xmqqshtrijdn.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqshtrijdn.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPPfXvLUtcBR6cYAP2dT8FAePFPjDSnVm8BhpLN9cfR1uw@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

>> Also this version fails to catch "bisect reset a b c" as an error, I
>> suspect.
>
> It didn't when I tried it right now. Could you please elaborate on why
> you think it can fail? There might be a thing which I haven't tested.

My bad.  I just compared your bisect_reset() implementation that had

    if (no specific commit) {
    	reset to the branch
    } else {
	reset to the commit
    }

with the original

    case $# in
    0)	reset to the branch ;;
    1)  reset to the commit ;;
    *)  give usage and die ;;
    esac

and took the difference and reacted "ah, excess parameters are not
diagnosed in this function".

Your caller does complain about excess parameters without giving
usage, and that is what I missed.

I am not sure if you intended to change the behaviour in this case
to avoid giving the usage string; I tend to think it is a good
change, but I didn't see it mentioned in the proposed commit log,
which also contributed to my not noticing the test in the caller.


```

## Junio C Hamano, 2016-08-26 20:56

Subject: Re: [PATCH v14 15/27] bisect--helper: retire `--bisect-clean-state` subcommand
Message-ID: <xmqq37lrfdvf.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq37lrfdvf.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6c6-60f4f6c2-9c39-4840-bbbf-18902961d57f-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> The `bisect-clean-state` subcommand is no longer used in the shell
> script while the C code uses `bisect_clean_state()` thus remove the
> subcommand.

Good.

```

## Junio C Hamano, 2016-08-26 21:09

Subject: Re: [PATCH v14 17/27] bisect--helper: `bisect_autostart` shell function in C
Message-ID: <xmqqy43jdyos.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqy43jdyos.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6d7-8b80c663-7c77-469e-811f-40200ec6dbb1-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> @@ -410,6 +413,7 @@ static int bisect_next(struct bisect_terms *terms, const char *prefix)
>  {
>  	int res, no_checkout;
>  
> +	bisect_autostart(terms);
>  	/* 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

This change is extremely hard to reason about.

Why wasn't auto-start done at the very beginning of this function
before?  Why does this start calling it all of a sudden?  Before
autostart was rewritten in C in this step, who made sure the shell
version of autostart was called before bisect_next is called (which
must have become unnecessary with this step, and I fully expected a
removal of such a call in the shell version, but I didn't find such
a change in this patch)?

Or is this series simply broken by lossage of autostart feature in
"bisect next" between the step where bisect_next is rewritten in C
and this step?


```

## Junio C Hamano, 2016-08-26 23:07

Subject: Re: [PATCH v14 21/27] bisect--helper: `bisect_log` shell function in C
Message-ID: <xmqqbn0fdt9e.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqbn0fdt9e.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6d5-6a363195-eb91-48a0-9a3c-3159fba6d327-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +static int bisect_log(void)
> +{
> +	struct strbuf buf = STRBUF_INIT;
> +
> +	if (strbuf_read_file(&buf, git_path_bisect_log(), 256) < 0) {
> +		strbuf_release(&buf);
> +		return error(_("We are not bisecting.\n"));
> +	}
> +
> +	printf("%s", buf.buf);
> +	strbuf_release(&buf);
> +
> +	return 0;
> +}

Hmph, is it really necessary to slurp everything in a strbuf before
sending it out to the standard output?  Wouldn't it be sufficient to
open a file descriptor for reading on the log file and then hand it
over to copy.c::copy_fd()?


```

## Junio C Hamano, 2016-08-26 23:24

Subject: Re: [PATCH v14 22/27] bisect--helper: `bisect_replay` shell function in C
Message-ID: <xmqq7fb3dsg9.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq7fb3dsg9.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <01020156b73fe6d7-6cd42223-f46c-4e4c-a15f-516fc13a4521-000000@eu-west-1.amazonses.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> +static int get_next_word(struct strbuf *line, struct strbuf *word)
> +{
> +	int i;
> +	for (i = 0; line->buf[i] != ' ' && line->buf[i] != '\0'; i++)
> +		strbuf_addch(word, line->buf[i]);
> +
> +	return 0;
> +}

This looks like a very non-standard way to use a string buffer.  The
function does not even have to take line as a whole strbuf, because
the logic does not even look at line->len and relies on line->buf[]
to be NUL terminated, which means the first parameter should instead
be "const char *buf", and the caller would feed then line.buf to the
function.

And I highly suspect that this is a very suboptimal interface, if
the caller then has to compute up to which byte in the line.buf to
splice away to get to the "next word" again.

A better alternative with higher level of abstraction would instead
be to keep the two strbuf parameters as-is, but have this function
responsible for "moving" the first word of "line" strbuf into "word"
strbuf.  Then the caller can repeatedly call this function to get
each word in "word" strbuf until "line" becomes empty if it wants to
implement "a word at a time" operation.

If that higher level of abstraction is too limiting for the caller
(and also that would be just as inefficient as the patch under
discussion), another alternative would be to have the caller
maintain "the current byte position in the input" and
do something like:

	int pos = 0;

	while (pos < line.len) {
                strbuf_reset(&word);
                get_next_word(line.buf, pos, word);
                pos += word.len;
		do a thing on "word";
	}

to implement "a word at a time" operation.  For this to work,
get_next_word() would need to skip the leading blanks itself, of
course.

In any case, I won't comment on the body of the function too deeply;
it will probably become a lot cleaner if you employed the "retval +
goto finish:" pattern for error handling.  Use of dequote seems
correct from the cursory look, too.


```

## Pranit Bauva, 2016-08-27 09:14

Subject: Re: [PATCH v14 08/27] bisect--helper: `is_expected_rev` & `check_expected_revs` shell function in C
Message-ID: <CAFZEwPP2j-+C=J-hiWEiW4wa=Yso27-M-QUABCTyd4WYieeezw@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPP2j-%2BC%3DJ-hiWEiW4wa%3DYso27-M-QUABCTyd4WYieeezw%40mail.gmail.com
In-Reply-To: <xmqqlgzlolwa.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Thu, Aug 25, 2016 at 3:43 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +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) >= 0) {
>> +             strbuf_trim(&actual_hex);
>> +             res = !strcmp(actual_hex.buf, expected_hex);
>
> If it is known to have 40-hex:
>
>  (1) accepting ">= 0" seems way too lenient.  You only expect a
>      41-byte file (or 42 if somebody would write CRLF, but I do not
>      think anybody other than yourself is expected to write into
>      this file, and you do not write CRLF yourself);
>
>  (2) strbuf_trim() is overly loose.  You only want to trim the
>      terimnating LF and it is an error to have other trailing
>      whitespaces.
>
> I think the latter is not a new problem and it is OK to leave it
> as-is; limiting (1) to >= 40 may still be a good change, though,
> because it makes the intention of the code clearer.

I can do the first change. Since this wasn't present in the shell
code, I will also mention it in the commit message.

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-27 09:33

Subject: Re: [PATCH v14 09/27] bisect--helper: `bisect_write` shell function in C
Message-ID: <CAFZEwPMcUf-Tm_ijJbEG1Bh7F+7ML2fw6Vw2Gt94B9gyoGL1FQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPMcUf-Tm_ijJbEG1Bh7F%2B7ML2fw6Vw2Gt94B9gyoGL1FQ%40mail.gmail.com
In-Reply-To: <xmqqfuptol4h.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Thu, Aug 25, 2016 at 4:00 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +struct bisect_terms {
>> +     struct strbuf term_good;
>> +     struct strbuf term_bad;
>> +};
>
> I think "struct strbuf" is overrated.  For things like this, where
> these fields will never change once it is set (and setting it is
> done atomically, not incrementally), there is no good reason to use
> define the fields as strbuf.
>
> Only because you chose to use strbuf for these two fields, you have
> to make unnecessarily copies of argv[] in the command parser, and
> you have to remember to discard these copies later.
>
> I think you can just say "const char *" in this case.

Using struct strbuf is not really overrated but in fact required. But
yes, for this patch it might seem as overrated. In the shell code
initally TERM_GOOD is set to "good" while TERM_BAD is set to "bad".
Now there are a lot of instances (one of which is bisect_start()
function) where this can change. So if we keep it as "const char *",
it would be right to change the value of it after wards. And we cannot
keep it as "char []" because we don't know its size before hand.

>> +static int bisect_write(const char *state, const char *rev,
>> +                     const struct bisect_terms *terms, int nolog)
>> +{
>> +     struct strbuf tag = STRBUF_INIT;
>> +     struct strbuf commit_name = STRBUF_INIT;
>> +     struct object_id oid;
>> +     struct commit *commit;
>> +     struct pretty_print_context pp = {0};
>> +     FILE *fp;
>> +
>> +     if (!strcmp(state, terms->term_bad.buf))
>> +             strbuf_addf(&tag, "refs/bisect/%s", state);
>> +     else if (one_of(state, terms->term_good.buf, "skip", NULL))
>> +             strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
>> +     else
>> +             return error(_("Bad bisect_write argument: %s"), state);
>
> OK.
>
>> +     if (get_oid(rev, &oid)) {
>> +             strbuf_release(&tag);
>> +             return error(_("couldn't get the oid of the rev '%s'"), rev);
>> +     }
>> +
>> +     if (update_ref(NULL, tag.buf, oid.hash, NULL, 0,
>> +                    UPDATE_REFS_MSG_ON_ERR)) {
>> +             strbuf_release(&tag);
>> +             return -1;
>> +     }
>> +     strbuf_release(&tag);
>> +
>> +     fp = fopen(git_path_bisect_log(), "a");
>> +     if (!fp)
>> +             return error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
>> +
>> +     commit = lookup_commit_reference(oid.hash);
>> +     format_commit_message(commit, "%s", &commit_name, &pp);
>> +     fprintf(fp, "# %s: [%s] %s\n", state, sha1_to_hex(oid.hash),
>> +             commit_name.buf);
>> +     strbuf_release(&commit_name);
>> +
>> +     if (!nolog)
>> +             fprintf(fp, "git bisect %s %s\n", state, rev);
>> +
>> +     fclose(fp);
>> +     return 0;
>
> You seem to be _release()ing tag all over the place.
>
> Would it make sense to have a single clean-up label at the end of
> function, introduce a "int retval" variable and set it to -1 (or
> whatever) when an error is detected and "goto" to the label?  It may
> make it harder to make such a leak.  That is, to end the function
> more like:

I think I could use goto for this function.

>         finish:
>                 if (fp)
>                         fclose(fp);
>                 strbuf_release(&tag);
>                 strbuf_release(&commit_name);
>                 return retval;
>         }
>
> and have sites with potential errors do something like this:
>
>         if (update_ref(...)) {
>                 retval = -1;
>                 goto finish;
>         }
>
>> +     struct bisect_terms terms;
>> +     bisect_terms_init(&terms);
>
> With the type of "struct bisect_terms" members corrected, you do not
> even need the _init() function.

Discussed above.

>> @@ -182,24 +251,38 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
>>               usage_with_options(git_bisect_helper_usage, options);
>>
>>       switch (cmdmode) {
>> +     int nolog;
>>       case NEXT_ALL:
>>               return bisect_next_all(prefix, no_checkout);
>>       case WRITE_TERMS:
>>               if (argc != 2)
>>                       die(_("--write-terms requires two arguments"));
>> -             return write_terms(argv[0], argv[1]);
>> +             res = write_terms(argv[0], argv[1]);
>> +             break;
>>       case BISECT_CLEAN_STATE:
>>               if (argc != 0)
>>                       die(_("--bisect-clean-state requires no arguments"));
>> -             return bisect_clean_state();
>> +             res = bisect_clean_state();
>> +             break;
>>       case BISECT_RESET:
>>               if (argc > 1)
>>                       die(_("--bisect-reset requires either zero or one arguments"));
>> -             return bisect_reset(argc ? argv[0] : NULL);
>> +             res = bisect_reset(argc ? argv[0] : NULL);
>> +             break;
>>       case CHECK_EXPECTED_REVS:
>> -             return check_expected_revs(argv, argc);
>> +             res = check_expected_revs(argv, argc);
>> +             break;
>> +     case BISECT_WRITE:
>> +             if (argc != 4 && argc != 5)
>> +                     die(_("--bisect-write requires either 4 or 5 arguments"));
>> +             nolog = (argc == 5) && !strcmp(argv[4], "nolog");
>> +             strbuf_addstr(&terms.term_good, argv[2]);
>> +             strbuf_addstr(&terms.term_bad, argv[3]);
>
> Here,
>
>         terms.term_good = argv[2];
>         terms.term_bad = argv[3];
>
> and then you do not need bisect_terms_release() at all.

Discussed above.

>> +             res = bisect_write(argv[0], argv[1], &terms, nolog);
>> +             break;
>>       default:
>>               die("BUG: unknown subcommand '%d'", cmdmode);
>>       }
>> -     return 0;
>> +     bisect_terms_release(&terms);
>> +     return res;
>>  }

```

## Pranit Bauva, 2016-08-27 09:35

Subject: Re: [PATCH v14 11/27] bisect--helper: `bisect_next_check` & bisect_voc shell function in C
Message-ID: <CAFZEwPOf=UBo9iCAQ+DfFmZTjSJuQ+v8KayUKpb+G19bUC+pmQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPOf%3DUBo9iCAQ%2BDfFmZTjSJuQ%2Bv8KayUKpb%2BG19bUC%2BpmQ%40mail.gmail.com
In-Reply-To: <xmqqbn0hoko0.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Thu, Aug 25, 2016 at 4:10 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +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 char *bisect_voc(char *revision_type)
>> +{
>> +     if (!strcmp(revision_type, "bad"))
>> +             return "bad|new";
>> +     if (!strcmp(revision_type, "good"))
>> +             return "good|old";
>> +
>> +     return NULL;
>> +}
>> +
>> +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.buf);
>> +     char *good_glob = xstrfmt("%s-*", terms->term_good.buf);
>> +     char *bad_syn, *good_syn;
>> +
>> +     if (ref_exists(bad_ref))
>> +             missing_bad = 0;
>> +     free(bad_ref);
>> +
>> +     for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
>> +                          (void *) &missing_good);
>> +     free(good_glob);
>> +
>> +     if (!missing_good && !missing_bad)
>> +             return 0;
>> +
>> +     if (!current_term)
>> +             return -1;
>> +
>> +     if (missing_good && !missing_bad && current_term &&
>> +         !strcmp(current_term, terms->term_good.buf)) {
>> +             char *yesno;
>> +             /*
>> +              * have bad (or new) but not good (or old). We could bisect
>> +              * although this is less optimum.
>> +              */
>> +             fprintf(stderr, _("Warning: bisecting only with a %s commit\n"),
>> +                     terms->term_bad.buf);
>> +             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;
>> +     }
>> +     bad_syn = xstrdup(bisect_voc("bad"));
>> +     good_syn = xstrdup(bisect_voc("good"));
>> +     if (!is_empty_or_missing_file(git_path_bisect_start())) {
>> +             error(_("You need to give me at least one %s and "
>> +                     "%s revision. You can use \"git bisect %s\" "
>> +                     "and \"git bisect %s\" for that. \n"),
>> +                     bad_syn, good_syn, bad_syn, good_syn);
>> +             free(bad_syn);
>> +             free(good_syn);
>> +             return -1;
>> +     }
>> +     else {
>> +             error(_("You need to start by \"git bisect start\". You "
>> +                     "then need to give me at least one %s and %s "
>> +                     "revision. You can use \"git bisect %s\" and "
>> +                     "\"git bisect %s\" for that.\n"),
>> +                     good_syn, bad_syn, bad_syn, good_syn);
>> +             free(bad_syn);
>> +             free(good_syn);
>> +             return -1;
>> +     }
>> +     free(bad_syn);
>> +     free(good_syn);
>> +
>> +     return 0;
>
> This one looks OK, but I think the same "Wouldn't it become cleaner
> to have a 'finish:' label at the end and jump there?" comment
> applies to this implementation, too.

For this goto can simply things. Will do!

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-27 09:48

Subject: Re: [PATCH v14 12/27] bisect--helper: `get_terms` & `bisect_terms` shell function in C
Message-ID: <CAFZEwPNTkgbFz-tcnLiaW9qvRSUoHgeNMzjnCjx7EwMHG71Niw@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPNTkgbFz-tcnLiaW9qvRSUoHgeNMzjnCjx7EwMHG71Niw%40mail.gmail.com
In-Reply-To: <xmqqmvk0n2pl.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Thu, Aug 25, 2016 at 11:35 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
>> +{
>> +     int i;
>> +
>> +     if (get_terms(terms)) {
>> +             fprintf(stderr, _("no terms defined\n"));
>> +             return -1;
>> +     }
>> +     if (argc == 0) {
>> +             printf(_("Your current terms are %s for the old state\nand "
>> +                    "%s for the new state.\n"), terms->term_good.buf,
>> +                    terms->term_bad.buf);
>> +             return 0;
>> +     }
>> +
>> +     for (i = 0; i < argc; i++) {
>> +             if (!strcmp(argv[i], "--term-good"))
>> +                     printf("%s\n", terms->term_good.buf);
>> +             else if (!strcmp(argv[i], "--term-bad"))
>> +                     printf("%s\n", terms->term_bad.buf);
>> +             else
>> +                     printf(_("invalid argument %s for 'git bisect "
>> +                               "terms'.\nSupported options are: "
>> +                               "--term-good|--term-old and "
>> +                               "--term-bad|--term-new."), argv[i]);
>> +     }
>
> The original took only one and gave one answer (and errored out when
> the user asked for more), but this one loops.  I can see either way
> is OK and do not think of a good reason to favor one over the other;
> unless there is a strong reason why you need this extended behaviour
> that allows users to ask multiple questions, I'd say we should keep
> the original behaviour.

True! I can just use return error() instead of printf. Also I noticed
that this is printing to stdout while the original printed it to
stderr. Thanks!

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-27 10:52

Subject: Re: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <CAFZEwPMBy0Ovcq-pUJkhoLiVF+uvm5fC0PD0RGPKobZ83Ciy3A@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPMBy0Ovcq-pUJkhoLiVF%2Buvm5fC0PD0RGPKobZ83Ciy3A%40mail.gmail.com
In-Reply-To: <xmqqshtrijdn.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Fri, Aug 26, 2016 at 9:59 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>>> Also this version fails to catch "bisect reset a b c" as an error, I
>>> suspect.
>>
>> It didn't when I tried it right now. Could you please elaborate on why
>> you think it can fail? There might be a thing which I haven't tested.
>
> My bad.  I just compared your bisect_reset() implementation that had
>
>     if (no specific commit) {
>         reset to the branch
>     } else {
>         reset to the commit
>     }
>
> with the original
>
>     case $# in
>     0)  reset to the branch ;;
>     1)  reset to the commit ;;
>     *)  give usage and die ;;
>     esac
>
> and took the difference and reacted "ah, excess parameters are not
> diagnosed in this function".
>
> Your caller does complain about excess parameters without giving
> usage, and that is what I missed.
>
> I am not sure if you intended to change the behaviour in this case
> to avoid giving the usage string; I tend to think it is a good
> change, but I didn't see it mentioned in the proposed commit log,
> which also contributed to my not noticing the test in the caller.

I could include this in the commit message. Its not really something
which we would want to test in the function because to the function,
we are not passing the raw arguments. Since we are removing that check
from the function but including it in cmd_bisect__helper(), I will
talk about it in the commit message.

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-27 19:47

Subject: Re: [PATCH v14 13/27] bisect--helper: `bisect_start` shell function partially in C
Message-ID: <CAFZEwPMotQ1k0EZN-buEt9MhJUKhXLS8eB5zV5A3Qr-j=DEwfQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPMotQ1k0EZN-buEt9MhJUKhXLS8eB5zV5A3Qr-j%3DDEwfQ%40mail.gmail.com
In-Reply-To: <xmqqd1kwn035.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Fri, Aug 26, 2016 at 12:32 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +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;
>> +     struct string_list revs = STRING_LIST_INIT_DUP;
>> +     struct string_list states = STRING_LIST_INIT_DUP;
>
> The original has a single state, not states.  Let's see if there is
> a reason behind the name change....
>
>> +     unsigned char sha1[20];
>> +     struct object_id oid;
>
> More on these below...
>
>> + ...
>> +     for (i = 0; i < argc; i++) {
>> +             const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
>> +             if (!strcmp(argv[i], "--")) {
>> +                     has_double_dash = 1;
>> +                     break;
>> +             } else if (!strcmp(argv[i], "--no-checkout"))
>> +                     no_checkout = 1;
>> +             else if (!strcmp(argv[i], "--term-good") ||
>> + ...
>> +             } else if (starts_with(argv[i], "--") &&
>> +                      !one_of(argv[i], "--term-good", "--term-bad", NULL)) {
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     die(_("unrecognised option: '%s'"), argv[i]);
>> +             } else if (get_oid(commit_id, &oid) && has_double_dash) {
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     die(_("'%s' does not appear to be a valid revision"), argv[i]);
>> +             } else {
>> +                     string_list_append(&revs, oid_to_hex(&oid));
>> +             }
>> +     }
>
> What I do not understand is clearing the string list "states" inside
> this loop.  It may have been INIT_DUPed, but nothing in this loop
> adds anything to it.  Because "revs" does get extended in the loop,
> it is understandable if you wanted to clear it before dying, but "if
> you are dying anyway why bother clearing?" is also a valid stance to
> take.

I think I should probably use return here instead of die().

> The same "perhaps want to use the 'retval' with goto 'finish:' pattern?"
> comment applies here, too.

Okay sure could do that.

>> +     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.
>> +      */
>> +     must_write_terms |= !!revs.nr;
>> +     for (i = 0; i < revs.nr; i++) {
>> +             if (bad_seen)
>> +                     string_list_append(&states, terms->term_good.buf);
>> +             else {
>> +                     bad_seen = 1;
>> +                     string_list_append(&states, terms->term_bad.buf);
>> +             }
>> +     }
>
> This is certainly different from the original.  We used to do one
> "bisect_write" per element in revs in the loop; we no longer do that
> and instead collect them in states list.  Each element in these two
> lists, i.e. revs.item[i] and states.item[i], corresponds to each
> other.
>
> That explains why the variable is renamed to states.  We haven't
> seen enough to say if this behaviour change is a good idea or not.
>
>> +     /*
>> +      * Verify HEAD
>> +      */
>> +     head = resolve_ref_unsafe("HEAD", 0, sha1, &flags);
>> +     if (!head) {
>> +             if (get_sha1("HEAD", sha1)) {
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     die(_("Bad HEAD - I need a HEAD"));
>> +             }
>> +     }
>> +     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)) {
>> +                             error(_("checking out '%s' failed. Try 'git "
>> +                                     "bisect start <valid-branch>'."),
>> +                                   start_head.buf);
>> +                             strbuf_release(&start_head);
>> +                             string_list_clear(&revs, 0);
>> +                             string_list_clear(&states, 0);
>> +                             return -1;
>
> The original died here, but you expect the caller to respond to a
> negative return.  I haven't read enough to judge if that is a good
> idea, but doesn't it make sense to do the same throughout the
> function consistently?  I saw a few die()'s already in the command
> line parsing loop--shouldn't they also return -1?

Yes they should use return rather than die().

> The original has called bisect_write already when we attempt this
> checkout and the user will see the states in the filesystem.  This
> rewrite does not.  What effect does this behaviour change have to
> the end-user experience?  The error message tells the end user to
> run another "git bisect start" with a valid commit, and when that
> happens, hopefully she will give us something we can check out, and
> then we will hit the bisect_clean_state() call we see below before
> starting to do anything meaningful, so I am guessing it won't, but
> I just want to make sure that you thought about the ramifications
> of the change above to delay calls to bisect_write.
>
>> +                     }
>> +             }
>> +     } else {
>> +             if (starts_with(head, "refs/heads/") ||
>> +                 !get_oid_hex(head, &oid) || ref_exists(head)) {
>
> This ref_exists() check is new, and I think it should not be there.
> In the original, if .git/HEAD pointed at refs/tags/v1.0, we would
> have diagnosed it as a strange symbolic ref.  This no longer does.
>
> If you wanted to make sure that the branch exists, it should have
> been
>
>         if ((starts_with(head, "refs/heads/") && ref_exists(head)) ||
>             !get_oid_hex(head, &oid)) {
>
> anyway.

I forgot to consider about tags. Thanks for reminding.

> Also, why do you use get_oid_hex() here?  You used get_sha1("HEAD",
> sha1) in the early part of "Verify HEAD" above, which seems to be
> perfectly adequate.  That sha1 taken from get_sha1() is what you end
> up using in the code below anyway.  If you can stick to one or the
> other, please do so.

I should use get_sha1().

>> +                     /*
>> +                      * 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())) {
>> +                             strbuf_release(&start_head);
>> +                             string_list_clear(&revs, 0);
>> +                             string_list_clear(&states, 0);
>> +                             die(_("won't bisect on cg-seek'ed tree"));
>> +                     }
>
> Not to be done as part of this series, but it probably is safe to
> retire this part by now.  Cogito has been dead for how many years?

Been around 10 years. Last update seemed around 2006. Here is the link[1].

>> +                     if (starts_with(head, "refs/heads/")) {
>> +                             strbuf_reset(&start_head);
>> +                             strbuf_addstr(&start_head, head + 11);
>
> skip_prefix?

Ya sure! That's a better way to go.

>> +                     }
>> +                     else {
>> +                             strbuf_reset(&start_head);
>> +                             strbuf_addstr(&start_head, sha1_to_hex(sha1));
>> +                     }
>> +             } else {
>> +                     strbuf_release(&start_head);
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     die(_("Bad HEAD - strange symbolic ref"));
>> +             }
>> +     }
>
> I wonder the whole thing above is better restructured to avoid
> repeated checks of the same thing.
>
>         if (is it 40-hex, i.e. detached?) {
>                 stuff it to start_head;
>         } else if (skip_prefix(head, "refs/heads/", &branchname)) {
>                 do the "cogito" check;
>                 stuff it to start_head;
>         } else {
>                 that's a strange symbolic ref HEAD you have there;
>         }

I guess it changes the behaviour. Its a strange symbolic ref if it
does not start with "refs/heads".

>> +     /*
>> +      * Get rid of any old bisect state.
>> +      */
>> +     if (bisect_clean_state()) {
>> +             return -1;
>> +     }
>
> If we are going to get a lot more code inside {} in later patches,
> then this single "return -1" enclosed inside a {} pair is
> justifiable (but in that case we'd prefer an empty line after it to
> separate it from the next comment block).  Otherwise lose the {}.

I had thought initially that I would need to keep something after
bisect_next() conversion. But it turns out that I actually don't.

>> +     /*
>> +      * 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".
>> +      */
>
> That explains the "trap" statements in the original.  Does it apply
> to this code here?
>
>> +     /*
>> +      * Write new start state
>> +      */
>> +     write_file(git_path_bisect_start(), "%s\n", start_head.buf);
>> +
>> +     if (no_checkout) {
>> +             get_oid(start_head.buf, &oid);
>> +             if (update_ref(NULL, "BISECT_HEAD", oid.hash, NULL, 0,
>> +                            UPDATE_REFS_MSG_ON_ERR)) {
>> +                     strbuf_release(&start_head);
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     return -1;
>> +             }
>> +     }
>> +     strbuf_release(&start_head);
>> +
>> +     if (pathspec_pos < argc - 1)
>> +             sq_quote_argv(&bisect_names, argv + pathspec_pos, 0);
>> +     write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
>> +     strbuf_release(&bisect_names);
>> +
>> +     for (i = 0; i < states.nr; i++) {
>> +             if (bisect_write(states.items[i].string,
>> +                               revs.items[i].string, terms, 1)) {
>> +                     string_list_clear(&revs, 0);
>> +                     string_list_clear(&states, 0);
>> +                     return -1;
>> +             }
>> +     }
>
> Hmph.  I do not particuarly see why doing this in a separate loop
> here, instead of doing it just like in the original, i.e. inside the
> loop we already saw, is an improvement.  It seems to me that the
> only effect of this change is to make the code more complex by
> forcing you to maintain (and clear) another string list "states" and
> have a separate loop here.
>
> Unless there is a reason why delaying calls to bisect_write() is a
> good thing and I am not seeing it, that is.
>
>> diff --git a/git-bisect.sh b/git-bisect.sh
>> index d6c8b5a..f0896b3 100755
>> --- a/git-bisect.sh
>> +++ b/git-bisect.sh
>> @@ -71,122 +71,7 @@ bisect_autostart() {
>>  }
>>
>>  bisect_start() {
>> -...
>> +     git bisect--helper --bisect-start $@ || exit
>>  ...
>> +     get_terms
>
> Understandable.  As the handling of the terms is done in the helper,
> you need to read the terms it left in the filesystem.  OK.
>
>>       bisect_auto_next


Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-27 20:16

Subject: Re: [PATCH v14 21/27] bisect--helper: `bisect_log` shell function in C
Message-ID: <CAFZEwPMWjyEzV7WsMynTOBhkgAT14eyoHdEmauAU8npq8mu0gg@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPMWjyEzV7WsMynTOBhkgAT14eyoHdEmauAU8npq8mu0gg%40mail.gmail.com
In-Reply-To: <xmqqbn0fdt9e.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Sat, Aug 27, 2016 at 4:37 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> +static int bisect_log(void)
>> +{
>> +     struct strbuf buf = STRBUF_INIT;
>> +
>> +     if (strbuf_read_file(&buf, git_path_bisect_log(), 256) < 0) {
>> +             strbuf_release(&buf);
>> +             return error(_("We are not bisecting.\n"));
>> +     }
>> +
>> +     printf("%s", buf.buf);
>> +     strbuf_release(&buf);
>> +
>> +     return 0;
>> +}
>
> Hmph, is it really necessary to slurp everything in a strbuf before
> sending it out to the standard output?  Wouldn't it be sufficient to
> open a file descriptor for reading on the log file and then hand it
> over to copy.c::copy_fd()?

That is actually much better. Thanks!

Regards,
Pranit Bauva

```

## Junio C Hamano, 2016-08-27 20:53

Subject: Re: [PATCH v14 13/27] bisect--helper: `bisect_start` shell function partially in C
Message-ID: <xmqqzinyc4s6.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqzinyc4s6.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPMotQ1k0EZN-buEt9MhJUKhXLS8eB5zV5A3Qr-j=DEwfQ@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

>> I wonder the whole thing above is better restructured to avoid
>> repeated checks of the same thing.
>>
>>         if (is it 40-hex, i.e. detached?) {
>>                 stuff it to start_head;
>>         } else if (skip_prefix(head, "refs/heads/", &branchname)) {
>>                 do the "cogito" check;
>>                 stuff it to start_head;
>>         } else {
>>                 that's a strange symbolic ref HEAD you have there;
>>         }
>
> I guess it changes the behaviour. Its a strange symbolic ref if it
> does not start with "refs/heads".

I did not think my suggestion would change the behaviour at all.  It
would change the code structure a bit to make it more readable, though.

```

## Junio C Hamano, 2016-08-27 21:22

Subject: Re: [PATCH v14 09/27] bisect--helper: `bisect_write` shell function in C
Message-ID: <xmqqtwe5di02.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqtwe5di02.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPMcUf-Tm_ijJbEG1Bh7F+7ML2fw6Vw2Gt94B9gyoGL1FQ@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

>>> +struct bisect_terms {
>>> +     struct strbuf term_good;
>>> +     struct strbuf term_bad;
>>> +};
>>
>> I think "struct strbuf" is overrated.  ...
>> I think you can just say "const char *" in this case.
>
> Using struct strbuf is not really overrated but in fact required. But

Nothing is required.

I can make your life easier by requiring you to never use struct
strbuf as a structure field type, though.  You will almost never
need it unless you are building something exotic anyway.

Step back and think what "strbuf" is good for.  It holds a pointer
to a piece of memory the field owns, over-allocates and knows the
size of allocation and usage.  That is good if you need to

 (1) frequently find out the length of the string; without a
     separate .len member you would have to run strlen().

 (2) incrementally add to the string in-place; as it overallocates,
     appending to the string would not have to involve realloc()
     every time and the cost of it is amortized.

 (3) make complex operations like splicing another string in,
     trimming substring out, etc.

You need to do none of the above to these fields.  term.term_good is
either taken from an argv[] element, or you read from a line from a
file and set it.  You may do some trivial computation and set it to
the result, like "the other field uses 'old', so this one need to be
set to 'new'".  The user of the field either has the string and sets
it there, or reads the field's value as a whole string.  No string
manipulation in the field in-place is needed.

> yes, for this patch it might seem as overrated. In the shell code
> initally TERM_GOOD is set to "good" while TERM_BAD is set to "bad".
> Now there are a lot of instances (one of which is bisect_start()
> function) where this can change. So if we keep it as "const char *",
> it would be right to change the value of it after wards. And we cannot
> keep it as "char []" because we don't know its size before hand.

You are not making sense.  Nobody would suggest to use a fixed-size
char array in this structure.  That wouldn't even work in the case
where you are stuffing what comes in an argv[] element in there,
e.g.

    terms.term_good = argv[3];

And you can of course support changing the value of the field
without using strbuf.  Just update the pointer to point at the piece
of memory that holds the new value.

In short, I do not see any good reason why the term_good field has
to be anything other than "char *term_good" or "const char *term_good".

Now, what you need to consider choosing between the two depends on
where these strings can come from.  If they are known to be always
unchanging between the time you set it til the end of the program
(e.g. using an element in argv[]), you can just assign without
making any copy and you can use "const char *term_good".  All other
cases, the structure needs to take the ownership, and you would need
to make a copy if you don't have the ownership, e.g.

	terms.term_good = xstrdup(argv[3]);

You may be reading from a file, a line at a time and you may have a
line's content in a strbuf.  You do not (yet) own the buffer after
reading it, e.g.

	strbuf_getline(&buf, fp);
	terms.term_good = strbuf_detach(&buf, NULL);

Of course, if you need to take ownership of the memory, you would
need to free(3) it as needed, which means the pattern to set the
field would become

	free(terms.term_good);
        terms.term_good = ... some new value ...;

Using strbuf as a local variable is good.  It gives a higher level
of abstraction when you are actually performing string operations.
In most applications, however, a field in a struct is where the
result of a step of computation is kept, not a scratch-pad to
perform steps of computation in.  When you are ready to update the
value of a field, you _have_ a completed string, and you can just
use "char *" field to point at it.  There is no need for strbuf in
the field.

Don't look at the data structure used in trailer.[ch] as a model; it
is an example of a terribly bad implementation taste, a pattern that
should not be followed.  Print it, not read it and burn it as a good
symbolic gesture.



```

## Junio C Hamano, 2016-08-29 17:06

Subject: Re: [PATCH v14 07/27] bisect--helper: `bisect_reset` shell function in C
Message-ID: <xmqqpoorcxnd.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqpoorcxnd.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPMBy0Ovcq-pUJkhoLiVF+uvm5fC0PD0RGPKobZ83Ciy3A@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

>> with the original
>>
>>     case $# in
>>     0)  reset to the branch ;;
>>     1)  reset to the commit ;;
>>     *)  give usage and die ;;
>>     esac
>>
>> and took the difference and reacted "ah, excess parameters are not
>> diagnosed in this function".
>>
>> Your caller does complain about excess parameters without giving
>> usage, and that is what I missed.
>>
>> I am not sure if you intended to change the behaviour in this case
>> to avoid giving the usage string; I tend to think it is a good
>> change, but I didn't see it mentioned in the proposed commit log,
>> which also contributed to my not noticing the test in the caller.
>
> I could include this in the commit message.

Nah, it was something anybody could notice with 2 more minutes of
reading and pondering from the patch text alone.  Not worth spending
more time on the log message on this one.

Thanks.

```

## Junio C Hamano, 2016-08-29 17:15

Subject: Re: [PATCH v14 12/27] bisect--helper: `get_terms` & `bisect_terms` shell function in C
Message-ID: <xmqqk2ezcx96.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqk2ezcx96.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPNTkgbFz-tcnLiaW9qvRSUoHgeNMzjnCjx7EwMHG71Niw@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

>>> +static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
>>> +{
>>> +     int i;
>>> +
>>> +     if (get_terms(terms)) {
>>> +             fprintf(stderr, _("no terms defined\n"));
>>> +             return -1;
>>> +     }
>>> +     if (argc == 0) {
>>> +             printf(_("Your current terms are %s for the old state\nand "
>>> +                    "%s for the new state.\n"), terms->term_good.buf,
>>> +                    terms->term_bad.buf);
>>> +             return 0;
>>> +     }
>>> +
>>> +     for (i = 0; i < argc; i++) {
>>> +             if (!strcmp(argv[i], "--term-good"))
>>> +                     printf("%s\n", terms->term_good.buf);
>>> +             else if (!strcmp(argv[i], "--term-bad"))
>>> +                     printf("%s\n", terms->term_bad.buf);
>>> +             else
>>> +                     printf(_("invalid argument %s for 'git bisect "
>>> +                               "terms'.\nSupported options are: "
>>> +                               "--term-good|--term-old and "
>>> +                               "--term-bad|--term-new."), argv[i]);
>>> +     }
>>
>> The original took only one and gave one answer (and errored out when
>> the user asked for more), but this one loops.  I can see either way
>> is OK and do not think of a good reason to favor one over the other;
>> unless there is a strong reason why you need this extended behaviour
>> that allows users to ask multiple questions, I'd say we should keep
>> the original behaviour.
>
> True! I can just use return error() instead of printf. Also I noticed
> that this is printing to stdout while the original printed it to
> stderr. Thanks!

The original you removed because the above can take it over is this
in your patch.

-bisect_terms () {
-	get_terms
-	if ! test -s "$GIT_DIR/BISECT_TERMS"
-	then
-		die "$(gettext "no terms defined")"
-	fi
-	case "$#" in
-	0)
-		gettextln "Your current terms are $TERM_GOOD for the old state
-and $TERM_BAD for the new state."
-		;;
-	1)
-		arg=$1
-		case "$arg" in
-			--term-good|--term-old)
-				printf '%s\n' "$TERM_GOOD"
-				;;
-			--term-bad|--term-new)
-				printf '%s\n' "$TERM_BAD"
-				;;
-			*)
-				die "$(eval_gettext "invalid argument \$arg for 'git bisect terms'.
-Supported options are: --term-good|--term-old and --term-bad|--term-new.")"
-				;;
-		esac
-		;;
-	*)
-		usage ;;
-	esac
-}
-

The fprintf() that says "no terms defined" can be made error().  The
"invalid argument" message used to be die in the original, and
should be sent to the standard error stream as you noticed.

But a bigger difference is that the original made sure that the
caller asked one question at a time.  "terms --term-good --term-bad"
was responded with a "usage".  That is no longer true in the
rewrite.


```

## Junio C Hamano, 2016-08-29 17:17

Subject: Re: [PATCH v14 08/27] bisect--helper: `is_expected_rev` & `check_expected_revs` shell function in C
Message-ID: <xmqqfupncx5s.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqfupncx5s.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPP2j-+C=J-hiWEiW4wa=Yso27-M-QUABCTyd4WYieeezw@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> Hey Junio,
>
> On Thu, Aug 25, 2016 at 3:43 AM, Junio C Hamano <gitster@pobox.com> wrote:
>> Pranit Bauva <pranit.bauva@gmail.com> writes:
>>
>>> +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) >= 0) {
>>> +             strbuf_trim(&actual_hex);
>>> +             res = !strcmp(actual_hex.buf, expected_hex);
>>
>> If it is known to have 40-hex:
>>
>>  (1) accepting ">= 0" seems way too lenient.  You only expect a
>>      41-byte file (or 42 if somebody would write CRLF, but I do not
>>      think anybody other than yourself is expected to write into
>>      this file, and you do not write CRLF yourself);
>>
>>  (2) strbuf_trim() is overly loose.  You only want to trim the
>>      terimnating LF and it is an error to have other trailing
>>      whitespaces.
>>
>> I think the latter is not a new problem and it is OK to leave it
>> as-is; limiting (1) to >= 40 may still be a good change, though,
>> because it makes the intention of the code clearer.
>
> I can do the first change. Since this wasn't present in the shell
> code, I will also mention it in the commit message.

There is no need for that, as that was present in the original.  The
original compared the string with something that is known to be
40-hex, so anything shorter than 40 wouldn't have matched.

It is merely a trivial and obvious optimization to do that in C
rewrite.

```

## Pranit Bauva, 2016-08-30 06:42

Subject: Re: [PATCH v14 09/27] bisect--helper: `bisect_write` shell function in C
Message-ID: <CAFZEwPMz4n35x-g3cxM4KaADRJNmYmZBnwsDZD1wiiFPHJebew@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPMz4n35x-g3cxM4KaADRJNmYmZBnwsDZD1wiiFPHJebew%40mail.gmail.com
In-Reply-To: <xmqqtwe5di02.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Sun, Aug 28, 2016 at 2:52 AM, Junio C Hamano <gitster@pobox.com> wrote:
>
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
> >>> +struct bisect_terms {
> >>> +     struct strbuf term_good;
> >>> +     struct strbuf term_bad;
> >>> +};
> >>
> >> I think "struct strbuf" is overrated.  ...
> >> I think you can just say "const char *" in this case.
> >
> > Using struct strbuf is not really overrated but in fact required. But
>
> Nothing is required.
>
> I can make your life easier by requiring you to never use struct
> strbuf as a structure field type, though.  You will almost never
> need it unless you are building something exotic anyway.
>
> Step back and think what "strbuf" is good for.  It holds a pointer
> to a piece of memory the field owns, over-allocates and knows the
> size of allocation and usage.  That is good if you need to
>
>  (1) frequently find out the length of the string; without a
>      separate .len member you would have to run strlen().
>
>  (2) incrementally add to the string in-place; as it overallocates,
>      appending to the string would not have to involve realloc()
>      every time and the cost of it is amortized.
>
>  (3) make complex operations like splicing another string in,
>      trimming substring out, etc.
>
> You need to do none of the above to these fields.  term.term_good is
> either taken from an argv[] element, or you read from a line from a
> file and set it.  You may do some trivial computation and set it to
> the result, like "the other field uses 'old', so this one need to be
> set to 'new'".  The user of the field either has the string and sets
> it there, or reads the field's value as a whole string.  No string
> manipulation in the field in-place is needed.
>
> > yes, for this patch it might seem as overrated. In the shell code
> > initally TERM_GOOD is set to "good" while TERM_BAD is set to "bad".
> > Now there are a lot of instances (one of which is bisect_start()
> > function) where this can change. So if we keep it as "const char *",
> > it would be right to change the value of it after wards. And we cannot
> > keep it as "char []" because we don't know its size before hand.
>
> You are not making sense.  Nobody would suggest to use a fixed-size
> char array in this structure.  That wouldn't even work in the case
> where you are stuffing what comes in an argv[] element in there,
> e.g.
>
>     terms.term_good = argv[3];
>
> And you can of course support changing the value of the field
> without using strbuf.  Just update the pointer to point at the piece
> of memory that holds the new value.
>
> In short, I do not see any good reason why the term_good field has
> to be anything other than "char *term_good" or "const char *term_good".
>
> Now, what you need to consider choosing between the two depends on
> where these strings can come from.  If they are known to be always
> unchanging between the time you set it til the end of the program
> (e.g. using an element in argv[]), you can just assign without
> making any copy and you can use "const char *term_good".  All other
> cases, the structure needs to take the ownership, and you would need
> to make a copy if you don't have the ownership, e.g.
>
>         terms.term_good = xstrdup(argv[3]);
>
> You may be reading from a file, a line at a time and you may have a
> line's content in a strbuf.  You do not (yet) own the buffer after
> reading it, e.g.
>
>         strbuf_getline(&buf, fp);
>         terms.term_good = strbuf_detach(&buf, NULL);
>
> Of course, if you need to take ownership of the memory, you would
> need to free(3) it as needed, which means the pattern to set the
> field would become
>
>         free(terms.term_good);
>         terms.term_good = ... some new value ...;
>
> Using strbuf as a local variable is good.  It gives a higher level
> of abstraction when you are actually performing string operations.
> In most applications, however, a field in a struct is where the
> result of a step of computation is kept, not a scratch-pad to
> perform steps of computation in.  When you are ready to update the
> value of a field, you _have_ a completed string, and you can just
> use "char *" field to point at it.  There is no need for strbuf in
> the field.
>
> Don't look at the data structure used in trailer.[ch] as a model; it
> is an example of a terribly bad implementation taste, a pattern that
> should not be followed.  Print it, not read it and burn it as a good
> symbolic gesture.

Thanks for explaining when to use strbuf. I am convinced that the
thing I am aiming for can be done with the help of "const char *".
Though I will have to use strbuf in get_terms() and detach the string
buffer from there as you have mentioned previously.

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-30 18:25

Subject: Re: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <CAFZEwPP-c00aNvDKoQFiCf_-tqrP3tAwwU6KAnswfMkjyoP3QQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPP-c00aNvDKoQFiCf_-tqrP3tAwwU6KAnswfMkjyoP3QQ%40mail.gmail.com
In-Reply-To: <xmqq37lsmw15.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

Sorry for a late replay.

On Fri, Aug 26, 2016 at 2:00 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> A lot of parts of bisect.c uses exit() and these signals are then
>> trapped in the `bisect_start` function. Since the shell script ceases
>> its existence it would be necessary to convert those exit() calls to
>> return statements so that errors can be reported efficiently in C code.
>
> Is efficiency really an issue?  I think the real reason is that it
> would make it impossible for the callers to handle errors, if you do
> not convert and let the error codepaths exit().

I think I put the word "efficiently" wrongly over here. Will omit it.

>> @@ -729,7 +735,7 @@ static struct commit **get_bad_and_good_commits(int *rev_nr)
>>       return rev;
>>  }
>>
>> -static void handle_bad_merge_base(void)
>> +static int handle_bad_merge_base(void)
>>  {
>>       if (is_expected_rev(current_bad_oid)) {
>>               char *bad_hex = oid_to_hex(current_bad_oid);
>> @@ -750,17 +756,18 @@ static void handle_bad_merge_base(void)
>>                               "between %s and [%s].\n"),
>>                               bad_hex, term_bad, term_good, bad_hex, good_hex);
>>               }
>> -             exit(3);
>> +             return 3;
>>       }
>>
>>       fprintf(stderr, _("Some %s revs are not ancestor of the %s rev.\n"
>>               "git bisect cannot work properly in this case.\n"
>>               "Maybe you mistook %s and %s revs?\n"),
>>               term_good, term_bad, term_good, term_bad);
>> -     exit(1);
>> +     bisect_clean_state();
>> +     return 1;
>
> What is the logic behind this function sometimes clean the state,
> and some other times do not, when it makes an error-return?  We see
> above that "return 3" codepath leaves the state behind.
>
> Either you forgot a necessary clean_state in "return 3" codepath,
> or you forgot to document why the distinction exists in the in-code
> comment for the function.  I cannot tell which, but I am leaning
> towards guessing that it is the former.

This is a very tricky one. I have purposely not included this after a
lot of testing. I have hand tested with the original git and with this
branch. The reason why anyone wouldn't be able to catch this is
because its not covered in the test suite. I am including a patch with
this as an attachment (because I am behind a proxy right now but don't
worry I will include this as a commit in the next series). The
original behaviour of git does not clean the bisect state when this
situation occurs. On another note which you might have missed that
bisect_clean_state() is purposely put before return 1 which is covered
by the test suite. You can try removing it and see that there is a
broken tes. tI was thinking of including the tests after the whole
conversion but now I think including this before will make the
conversion more easier for review.

>> -static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
>> +static int check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
>>  {
>>       char *filename = git_pathdup("BISECT_ANCESTORS_OK");
>>       struct stat st;
>> -     int fd;
>> +     int fd, res = 0;
>>
>>       if (!current_bad_oid)
>>               die(_("a %s revision is needed"), term_bad);
>
> Can you let it die yere?

Not really. I should change it to return error().

>> @@ -873,8 +890,11 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
>>                             filename);
>>       else
>>               close(fd);
>> +
>> +     return 0;
>>   done:
>>       free(filename);
>> +     return 0;
>>  }
>
> Who owns "filename"?  The first "return 0" leaves it unfreed, and
> when "goto done" is done, it is freed.
>
> The above two may indicate that "perhaps 'retval + goto finish'
> pattern?" is a really relevant suggestion for the earlier steps in
> this series.

Yes.

>>       if (!all) {
>>               fprintf(stderr, _("No testable commit found.\n"
>>                       "Maybe you started with bad path parameters?\n"));
>> -             exit(4);
>> +             return 4;
>>       }
>>
>>       bisect_rev = revs.commits->item->object.oid.hash;
>>
>>       if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
>> -             exit_if_skipped_commits(tried, current_bad_oid);
>> +             res = exit_if_skipped_commits(tried, current_bad_oid);
>> +             if (res)
>> +                     return res;
>> +
>>               printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),
>>                       term_bad);
>>               show_diff_tree(prefix, revs.commits->item);
>>               /* This means the bisection process succeeded. */
>> -             exit(10);
>> +             return 10;
>>       }
>>
>>       nr = all - reaches - 1;
>> @@ -1005,7 +1033,11 @@ int bisect_next_all(const char *prefix, int no_checkout)
>>                 "Bisecting: %d revisions left to test after this %s\n",
>>                 nr), nr, steps_msg);
>>
>> -     return bisect_checkout(bisect_rev, no_checkout);
>> +     res = bisect_checkout(bisect_rev, no_checkout);
>> +     if (res)
>> +             bisect_clean_state();
>> +
>> +     return res;
>>  }
>
> There were tons of "exit_if" that was converted to "if (res) return
> res" above, instead of jumping here to cause clean_state to be
> called.  I cannot tell if this new call to clean_state() is wrong,
> or all the earlier "return res" should come here.  I am guessing the
> latter.

No I don't think its wrong. It is advised in the comment
    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".

to clean the bisection state *iff checkout fails* otherwise not.
Luckily this is already covered by the test suite. I think what you
meant is that bisect_clean_state() might be covered elsewhere too then
why perform cleanup here, right? bisect_clean_state() have been
carefully put where ever required only.

>> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
>> index c64996a..ef7b3a1 100644
>> --- a/builtin/bisect--helper.c
>> +++ b/builtin/bisect--helper.c
>> @@ -8,6 +8,7 @@
>>  #include "run-command.h"
>>  #include "prompt.h"
>>  #include "quote.h"
>> +#include "revision.h"
>>
>>  static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
>>  static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
>> @@ -29,6 +30,8 @@ static const char * const git_bisect_helper_usage[] = {
>>       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>...]"),
>> +     N_("git bisect--helper --bisect-next"),
>> +     N_("git bisect--helper --bisect-auto-next"),
>>       NULL
>>  };
>>
>> @@ -396,6 +399,129 @@ static int bisect_terms(struct bisect_terms *terms, const char **argv, int argc)
>>       return 0;
>>  }
>>
>> +static int register_good_ref(const char *refname,
>> +                          const struct object_id *oid, int flags,
>> +                          void *cb_data)
>> +{
>> +     struct string_list *good_refs = cb_data;
>> +     string_list_append(good_refs, oid_to_hex(oid));
>> +     return 0;
>> +}
>> +
>> +static int bisect_next(struct bisect_terms *terms, const char *prefix)
>> +{
>> +     int res, no_checkout;
>> +
>> +     /* In case of mistaken revs or checkout error, or signals received,
>
> That's an unbalanced comment.  You end the block with "*/" on its
> own line, so you should start the block with "/*" on its own line.
> There seems to be at least one more such comment in this patch but I
> won't repeat.

I shall change this.

>> +      * "bisect_auto_next" below may exit or misbehave.
>> +      * We have to trap this to be able to clean up using
>> +      * "bisect_clean_state".
>> +      */
>
> "exit" meaning "call exit() to terminate the process", or something
> else?  If the latter, don't say "exit", but say "return error".

Yes I think its necessary to change "exit" in comments to "return".
There are other places too in which I will have to change.

>> +     if (bisect_next_check(terms, terms->term_good.buf))
>> +             return -1;
>
> Mental note.  The "autostart" in the original is gone.  Perhaps it
> is done by next_check in this code, but we haven't seen that yet.

This will be added back again in a coming patch[1].

>> +     no_checkout = !is_empty_or_missing_file(git_path_bisect_head());
>> +
>> +     /* Perform all bisection computation, display and checkout */
>> +     res = bisect_next_all(prefix , no_checkout);
>> +
>> +     if (res == 10) {
>> +             FILE *fp;
>> +             unsigned char sha1[20];
>> +             struct commit *commit;
>> +             struct pretty_print_context pp = {0};
>> +             struct strbuf commit_name = STRBUF_INIT;
>> +             char *bad_ref = xstrfmt("refs/bisect/%s",
>> +                                           terms->term_bad.buf);
>> +             read_ref(bad_ref, sha1);
>> +             commit = lookup_commit_reference(sha1);
>> +             format_commit_message(commit, "%s", &commit_name, &pp);
>> +             fp = fopen(git_path_bisect_log(), "a");
>> +             if (!fp) {
>> +                     free(bad_ref);
>> +                     strbuf_release(&commit_name);
>> +                     return -1;
>> +             }
>> +             if (fprintf(fp, "# first %s commit: [%s] %s\n",
>> +                         terms->term_bad.buf, sha1_to_hex(sha1),
>> +                         commit_name.buf) < 1){
>> +                     free(bad_ref);
>> +                     strbuf_release(&commit_name);
>> +                     fclose(fp);
>> +                     return -1;
>> +             }
>> +             free(bad_ref);
>> +             strbuf_release(&commit_name);
>> +             fclose(fp);
>> +             return 0;
>
> Doesn't it bother you that you have to write free(bad_ref)...fclose(fp)
> repeatedly?

My mind was more involved in the actual conversion and that was the
main part bothering me. I did all the "clean up" stuff after I did the
actual conversion. And since I was extremely happy after the porting
happened, the "cleanup stuff" didn't bother me much.

>> +     }
>> +     else if (res == 2) {
>> +             FILE *fp;
>> +             struct rev_info revs;
>> +             struct argv_array rev_argv = ARGV_ARRAY_INIT;
>> +             struct string_list good_revs = STRING_LIST_INIT_DUP;
>> +             struct pretty_print_context pp = {0};
>> +             struct commit *commit;
>> +             char *term_good = xstrfmt("%s-*", terms->term_good.buf);
>> +             int i;
>> +
>> +             fp = fopen(git_path_bisect_log(), "a");
>> +             if (!fp) {
>> +                     free(term_good);
>> +                     return -1;
>> +             }
>> +             if (fprintf(fp, "# only skipped commits left to test\n") < 1) {
>> +                     free(term_good);
>> +                     fclose(fp);
>> +                     return -1;
>> +             }
>> +             for_each_glob_ref_in(register_good_ref, term_good,
>> +                                  "refs/bisect/", (void *) &good_revs);
>> +
>> +             free(term_good);
>
> Doesn't it bother you that you have to write free(term_good) repeatedly?
>
>> +             argv_array_pushl(&rev_argv, "skipped_commits", "refs/bisect/bad", "--not", NULL);
>> +             for (i = 0; i < good_revs.nr; i++)
>> +                     argv_array_push(&rev_argv, good_revs.items[i].string);
>> +
>> +             /* It is important to reset the flags used by revision walks
>> +              * as the previous call to bisect_next_all() in turn
>> +              * setups a revision walk.
>> +              */
>> +             reset_revision_walk();
>> +             init_revisions(&revs, NULL);
>> +             rev_argv.argc = setup_revisions(rev_argv.argc, rev_argv.argv, &revs, NULL);
>> +             argv_array_clear(&rev_argv);
>> +             string_list_clear(&good_revs, 0);
>
> Are you sure that the revision walking machinery is prepared to see
> the argv[] and elements in it you have given to setup_revisions()
> gets cleared before it starts doing the real work in
> prepare_revision_walk()?  I am reasonably sure that the machinery
> borrows strings like pathspec elements from the caller and expects
> them to stay during revision traversal.

I have extremely little understanding of revision walking. All what I
know about revision walking is what's covered in
Documentation/technical/api-revision-walking.txt . There it is
mentioned that for multiple revision walking its necessary to reset.
What's happening is that there are multiple calls for revision
walking. Now bisect_next() in itself calls for revision walking two
times (the first one being with bisect_next_all and the next one
conditionally with skip).  This is also the reason why I included a
reset_revision_walk() in bisect.c too in this patch. Before what used
to happen is that when git plumbing commands were called there was no
previous need for resetting the revision walk.  Now that only a C code
exists after bisect_replay() conversion (I faced a problem in a
futuristic patch and thought it would be better to cover it up here),
there would be multiple calls to bisect_next(). Previously it wasn't a
problem because bisect_next_all() was a subcommand called from shell
script and for "skip" it was git-rev-list which did revision walking
as a separate thing. I didn't do reset previously and because of this
I used to get a NULL value in the revs.commits . It would be really
helpful if you could look more into it.

> You seem to have acquired a habit of freeing and clearing things
> early, which is bad.  Instead, make it a habit of free/clear at the
> end, and make sure all error paths go through that central freeing
> site.  That tends to future-proof your code better from leaking even
> when later other people change it.

Sure!

>> +             if (prepare_revision_walk(&revs)) {
>> +                     die(_("revision walk setup failed\n"));
>> +             }
>
> This one is still allowed to die, without clean_state?

I couldn't really test this part of code because I don't know how to
make this call fail. And this isn't covered by the test suite either.
BTW, here also it should be return error().

>> +             while ((commit = get_revision(&revs)) != NULL) {
>> +                     struct strbuf commit_name = STRBUF_INIT;
>> +                     format_commit_message(commit, "%s",
>> +                                           &commit_name, &pp);
>> +                     fprintf(fp, "# possible first %s commit: "
>> +                                 "[%s] %s\n", terms->term_bad.buf,
>> +                                 oid_to_hex(&commit->object.oid),
>> +                                 commit_name.buf);
>> +                     strbuf_release(&commit_name);
>> +             }
>> +
>> +             fclose(fp);
>> +             return res;
>> +     }
>> +
>> +     return res;
>> +}
>
>> @@ -415,47 +541,67 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
>>               no_checkout = 1;
>>
>>       for (i = 0; i < argc; i++) {
>> -             if (!strcmp(argv[i], "--")) {
>> +             const char *arg;
>> +             if (starts_with(argv[i], "'"))
>> +                     arg = sq_dequote(xstrdup(argv[i]));
>> +             else
>> +                     arg = argv[i];
>> +             if (!strcmp(arg, "--")) {
>>                       has_double_dash = 1;
>>                       break;
>>               }
>>       }
>
> This is really bad; you are blindly assuming that anything that
> begins with " ' " begins with " ' " because "git-bisect.sh" sq-quoted
> and it never directly came from the command line that _wanted_ to
> give you something that begins with a " ' ".
>
> I suspect that you should be able to dequote on the calling script
> side.  Then all these ugliness would disappear.

I had an unsuccessful attempt at it. Though this ugliness is removed
in the patch[2]. This is specifically because of the line in
bisect_replay() shell function which calls bisect_start().

>>       for (i = 0; i < argc; i++) {
>> -             const char *commit_id = xstrfmt("%s^{commit}", argv[i]);
>> +             const char *arg, *commit_id;
>> +             if (starts_with(argv[i], "'"))
>> +                     arg = sq_dequote(xstrdup(argv[i]));
>> +             else
>> +                     arg = argv[i];
>
> Likewise.
>
>> +             commit_id = xstrfmt("%s^{commit}", arg);
>
> In any case, I think a separate "const char *arg" that is an alias
> to argv[i] in the loop is a very good idea to do from the very
> beginning (i.e. should be done in a much much earlier patch in this
> series).

I will do it in the earlier patch.

[1]: http://public-inbox.org/git/01020156b73fe6d7-8b80c663-7c77-469e-811f-40200ec6dbb1-000000@eu-west-1.amazonses.com/
[2]: https://public-inbox.org/git/01020156b73fe6e4-d45cf1f7-03a3-4566-95d1-73788c5ab2f9-000000@eu-west-1.amazonses.com/

Regards,
Pranit Bauva

```

## Pranit Bauva, 2016-08-30 18:44

Subject: Re: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <CAFZEwPOt6aXA+URVzH8_=U+D=sMN=+Brp+15T=RWA=+D09fP9Q@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPOt6aXA%2BURVzH8_%3DU%2BD%3DsMN%3D%2BBrp%2B15T%3DRWA%3D%2BD09fP9Q%40mail.gmail.com
In-Reply-To: <CAFZEwPP-c00aNvDKoQFiCf_-tqrP3tAwwU6KAnswfMkjyoP3QQ@mail.gmail.com>

```
Hey Junio,

On Tue, Aug 30, 2016 at 11:55 PM, Pranit Bauva <pranit.bauva@gmail.com> wrote:
>
>>> @@ -729,7 +735,7 @@ static struct commit **get_bad_and_good_commits(int *rev_nr)
>>>       return rev;
>>>  }
>>>
>>> -static void handle_bad_merge_base(void)
>>> +static int handle_bad_merge_base(void)
>>>  {
>>>       if (is_expected_rev(current_bad_oid)) {
>>>               char *bad_hex = oid_to_hex(current_bad_oid);
>>> @@ -750,17 +756,18 @@ static void handle_bad_merge_base(void)
>>>                               "between %s and [%s].\n"),
>>>                               bad_hex, term_bad, term_good, bad_hex, good_hex);
>>>               }
>>> -             exit(3);
>>> +             return 3;
>>>       }
>>>
>>>       fprintf(stderr, _("Some %s revs are not ancestor of the %s rev.\n"
>>>               "git bisect cannot work properly in this case.\n"
>>>               "Maybe you mistook %s and %s revs?\n"),
>>>               term_good, term_bad, term_good, term_bad);
>>> -     exit(1);
>>> +     bisect_clean_state();
>>> +     return 1;
>>
>> What is the logic behind this function sometimes clean the state,
>> and some other times do not, when it makes an error-return?  We see
>> above that "return 3" codepath leaves the state behind.
>>
>> Either you forgot a necessary clean_state in "return 3" codepath,
>> or you forgot to document why the distinction exists in the in-code
>> comment for the function.  I cannot tell which, but I am leaning
>> towards guessing that it is the former.
>
> This is a very tricky one. I have purposely not included this after a
> lot of testing. I have hand tested with the original git and with this
> branch. The reason why anyone wouldn't be able to catch this is
> because its not covered in the test suite. I am including a patch with
> this as an attachment (because I am behind a proxy right now but don't
> worry I will include this as a commit in the next series). The
> original behaviour of git does not clean the bisect state when this
> situation occurs. On another note which you might have missed that
> bisect_clean_state() is purposely put before return 1 which is covered
> by the test suite. You can try removing it and see that there is a
> broken tes. tI was thinking of including the tests after the whole
> conversion but now I think including this before will make the
> conversion more easier for review.

The patch which I included as an attachment before will fail for
different reasons if you apply it on master branch. To test it on
master branch use the current attachment. Again sorry I couldn't
include this in the email itself.

Regards,
Pranit Bauva

```

## Junio C Hamano, 2016-08-30 19:33

Subject: Re: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <xmqqvayi2grg.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqvayi2grg.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAFZEwPP-c00aNvDKoQFiCf_-tqrP3tAwwU6KAnswfMkjyoP3QQ@mail.gmail.com>

```
Pranit Bauva <pranit.bauva@gmail.com> writes:

> This is a very tricky one. I have purposely not included this after a
> lot of testing. I have hand tested with the original git and with this
> branch. The reason why anyone wouldn't be able to catch this is
> because its not covered in the test suite. I am including a patch with
> this as an attachment (because I am behind a proxy right now but don't
> worry I will include this as a commit in the next series). The
> original behaviour of git does not clean the bisect state when this
> situation occurs.

"We sometimes clean and we sometimes don't and this follows the
original" may be a valid justification but it is not a very useful
explanation.  The real issue is if not cleaning is intended (and if
so why; otherwise, if it is clear that it is simply forgotten, we
can just fix it in the series as a follow-up step).

If not cleaning in some cases (but not others) is the right thing,
at least there needs an in-code comment to warn others against
"fixing" the lack of cleanups (e.g. "don't clean state here, because
the caller still wants to see what state we were for this and that
reason").

>>> +     if (bisect_next_check(terms, terms->term_good.buf))
>>> +             return -1;
>>
>> Mental note.  The "autostart" in the original is gone.  Perhaps it
>> is done by next_check in this code, but we haven't seen that yet.
>
> This will be added back again in a coming patch[1].

In other words, this series is broken at this step and the breakage
stay with the codebase until a later step?

I do not know if reordering the patches in the series is enough to
fix that, or if it is even worth to avoid such a temporary breakage.
It depends on how serious the circularity is, but I would understand
if it is too hard and not worth the effort (I think in a very early
review round some people advised against the bottom-up rewrite
because they anticipated this exact reason).  At least the omission
(and later resurrection) needs to be mentioned in the log so that
people understand what is going on when they later need to bisect.

Thanks.

```

## Pranit Bauva, 2016-08-30 20:17

Subject: Re: [PATCH v14 14/27] bisect--helper: `bisect_next` and `bisect_auto_next` shell function in C
Message-ID: <CAFZEwPOb2HhULRyPqdnZd-_ADgnSeZsdikgG4odvD_svWMJgCQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAFZEwPOb2HhULRyPqdnZd-_ADgnSeZsdikgG4odvD_svWMJgCQ%40mail.gmail.com
In-Reply-To: <xmqqvayi2grg.fsf@gitster.mtv.corp.google.com>

```
Hey Junio,

On Wed, Aug 31, 2016 at 1:03 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> This is a very tricky one. I have purposely not included this after a
>> lot of testing. I have hand tested with the original git and with this
>> branch. The reason why anyone wouldn't be able to catch this is
>> because its not covered in the test suite. I am including a patch with
>> this as an attachment (because I am behind a proxy right now but don't
>> worry I will include this as a commit in the next series). The
>> original behaviour of git does not clean the bisect state when this
>> situation occurs.
>
> "We sometimes clean and we sometimes don't and this follows the
> original" may be a valid justification but it is not a very useful
> explanation.  The real issue is if not cleaning is intended (and if
> so why; otherwise, if it is clear that it is simply forgotten, we
> can just fix it in the series as a follow-up step).

I think we do want to recover from this "bad merge base" state and for
that not cleaning up is essential. The original behaviour of git seems
natural to me.

> If not cleaning in some cases (but not others) is the right thing,
> at least there needs an in-code comment to warn others against
> "fixing" the lack of cleanups (e.g. "don't clean state here, because
> the caller still wants to see what state we were for this and that
> reason").

I will mention it in the comments.

>>>> +     if (bisect_next_check(terms, terms->term_good.buf))
>>>> +             return -1;
>>>
>>> Mental note.  The "autostart" in the original is gone.  Perhaps it
>>> is done by next_check in this code, but we haven't seen that yet.
>>
>> This will be added back again in a coming patch[1].
>
> In other words, this series is broken at this step and the breakage
> stay with the codebase until a later step?

Broken though it passes the test suite.

> I do not know if reordering the patches in the series is enough to
> fix that, or if it is even worth to avoid such a temporary breakage.
> It depends on how serious the circularity is, but I would understand
> if it is too hard and not worth the effort (I think in a very early
> review round some people advised against the bottom-up rewrite
> because they anticipated this exact reason).  At least the omission
> (and later resurrection) needs to be mentioned in the log so that
> people understand what is going on when they later need to bisect.

bisect_autostart() call from bisect_next() was introduced in the
earliest version of git-bisect in the commit 8cc6a0831 but it isn't
really a very big deal and I think it would be OK to skip it for a
very little while as any which ways the series in the end would fix
it. It is important to mention this in the commit message and I will
do it.

Regards,
Pranit Bauva

```