bisect--helper: `get_terms` & `bisect_terms` shell function in C

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.

Also use error() to report "no terms defined" and accordingly change the
test in t6030.

We need to use PARSE_OPT_KEEP_UNKNOWN here to allow for parameters that
look like options (e.g --term-good) but should not be parsed by
cmd_bisect__helper(). This change is safe because all other cmdmodes have
strict argc checks already.

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

1 files changed, 60 insertions, 2 deletions

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 38ae825b9ad..d61edd3c911 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 [--no-log] <state> <revision> <good_term> <bad_term>"),
 	N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
 	N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
+	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
 	NULL
 };
 
@@ -339,6 +340,55 @@ finish:
 	return retval;
 }
 
+static int get_terms(struct bisect_terms *terms)
+{
+	struct strbuf str = STRBUF_INIT;
+	FILE *fp = NULL;
+	int res = 0;
+
+	fp = fopen(git_path_bisect_terms(), "r");
+	if (!fp) {
+		res = -1;
+		goto finish;
+	}
+
+	free_terms(terms);
+	strbuf_getline_lf(&str, fp);
+	terms->term_bad = strbuf_detach(&str, NULL);
+	strbuf_getline_lf(&str, fp);
+	terms->term_good = strbuf_detach(&str, NULL);
+
+finish:
+	if (fp)
+		fclose(fp);
+	strbuf_release(&str);
+	return res;
+}
+
+static int bisect_terms(struct bisect_terms *terms, const char *option)
+{
+	if (get_terms(terms))
+		return error(_("no terms defined"));
+
+	if (option == NULL) {
+		printf(_("Your current terms are %s for the old state\n"
+			 "and %s for the new state.\n"),
+		       terms->term_good, terms->term_bad);
+		return 0;
+	}
+	if (one_of(option, "--term-good", "--term-old", NULL))
+		printf("%s\n", terms->term_good);
+	else if (one_of(option, "--term-bad", "--term-new", NULL))
+		printf("%s\n", terms->term_bad);
+	else
+		return error(_("invalid argument %s for 'git bisect terms'.\n"
+			       "Supported options are: "
+			       "--term-good|--term-old and "
+			       "--term-bad|--term-new."), option);
+
+	return 0;
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -349,7 +399,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_RESET,
 		BISECT_WRITE,
 		CHECK_AND_SET_TERMS,
-		BISECT_NEXT_CHECK
+		BISECT_NEXT_CHECK,
+		BISECT_TERMS
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0, nolog = 0;
 	struct option options[] = {
@@ -369,6 +420,8 @@ 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_BOOL(0, "no-log", &nolog,
@@ -378,7 +431,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 
 	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);
@@ -419,6 +472,11 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		set_terms(&terms, argv[1], argv[0]);
 		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 		break;
+	case BISECT_TERMS:
+		if (argc > 1)
+			return error(_("--bisect-terms requires 0 or 1 argument"));
+		res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
+		break;
 	default:
 		return error("BUG: unknown subcommand '%d'", cmdmode);
 	}