bisect--helper: is_expected_rev & check_expected_revs shell function in C

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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pranitbauva1997

builtin/bisect--helper.c

@@ -5,6 +5,8 @@
 #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 const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --next-all [--no-checkout]"),
@@ -80,12 +82,37 @@ static int write_terms(const char *bad, const char *good)
 	return (res < 0) ? -1 : 0;
 }
 
+static int is_expected_rev(const char *expected_hex)
+{
+	struct strbuf actual_hex = STRBUF_INIT;
+	int res = 0;
+	if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
+		strbuf_trim(&actual_hex);
+		res = !strcmp(actual_hex.buf, expected_hex);
+	}
+	strbuf_release(&actual_hex);
+	return res;
+}
+
+static void check_expected_revs(const char **revs, int rev_nr)
+{
+	int i;
+
+	for (i = 0; i < rev_nr; i++) {
+		if (!is_expected_rev(revs[i])) {
+			unlink_or_warn(git_path_bisect_ancestors_ok());
+			unlink_or_warn(git_path_bisect_expected_rev());
+		}
+	}
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
 		NEXT_ALL = 1,
 		WRITE_TERMS,
-		BISECT_CLEAN_STATE
+		BISECT_CLEAN_STATE,
+		CHECK_EXPECTED_REVS
 	} cmdmode = 0;
 	int no_checkout = 0;
 	struct option options[] = {
@@ -95,6 +122,8 @@ 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, "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()
@@ -117,6 +146,9 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		if (argc != 0)
 			return error(_("--bisect-clean-state requires no arguments"));
 		return bisect_clean_state();
+	case CHECK_EXPECTED_REVS:
+		check_expected_revs(argv, argc);
+		return 0;
 	default:
 		return error("BUG: unknown subcommand '%d'", cmdmode);
 	}

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.")" ;;
 	*)