repo: add the flag -z as an alias for --format=nul

Other Git commands that have nul-terminated output (e.g. git-config,
git-status, git-ls-files) have a flag `-z` for using the null character
as the record separator.

Add the `-z` flag to git-repo-info as an alias for `--format=nul`,
making it consistent with the behavior of the other commands.

Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Mentored-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: lucasoshiro

Documentation/git-repo.adoc

@@ -8,7 +8,7 @@ git-repo - Retrieve information about the repository
 SYNOPSIS
 --------
 [synopsis]
-git repo info [--format=(keyvalue|nul)] [<key>...]
+git repo info [--format=(keyvalue|nul)] [-z] [<key>...]
 
 DESCRIPTION
 -----------
@@ -18,7 +18,7 @@ THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOR MAY CHANGE.
 
 COMMANDS
 --------
-`info [--format=(keyvalue|nul)] [<key>...]`::
+`info [--format=(keyvalue|nul)] [-z] [<key>...]`::
 	Retrieve metadata-related information about the current repository. Only
 	the requested data will be returned based on their keys (see "INFO KEYS"
 	section below).
@@ -40,6 +40,8 @@ supported:
 	between the key and the value and using a NUL character after each value.
 	This format is better suited for being parsed by another applications than
 	`keyvalue`. Unlike in the `keyvalue` format, the values are never quoted.
++
+`-z` is an alias for `--format=nul`.
 
 INFO KEYS
 ---------

builtin/repo.c

@@ -9,7 +9,7 @@
 #include "shallow.h"
 
 static const char *const repo_usage[] = {
-	"git repo info [--format=(keyvalue|nul)] [<key>...]",
+	"git repo info [--format=(keyvalue|nul)] [-z] [<key>...]",
 	NULL
 };
 
@@ -112,26 +112,40 @@ static int print_fields(int argc, const char **argv,
 	return ret;
 }
 
+static int parse_format_cb(const struct option *opt,
+			   const char *arg, int unset UNUSED)
+{
+	enum output_format *format = opt->value;
+
+	if (opt->short_name == 'z')
+		*format = FORMAT_NUL_TERMINATED;
+	else if (!strcmp(arg, "nul"))
+		*format = FORMAT_NUL_TERMINATED;
+	else if (!strcmp(arg, "keyvalue"))
+		*format = FORMAT_KEYVALUE;
+	else
+		die(_("invalid format '%s'"), arg);
+
+	return 0;
+}
+
 static int repo_info(int argc, const char **argv, const char *prefix,
 		     struct repository *repo)
 {
-	const char *format_str = "keyvalue";
-	enum output_format format;
+	enum output_format format = FORMAT_KEYVALUE;
 	struct option options[] = {
-		OPT_STRING(0, "format", &format_str, N_("format"),
-			   N_("output format")),
+		OPT_CALLBACK_F(0, "format", &format, N_("format"),
+			       N_("output format"),
+			       PARSE_OPT_NONEG, parse_format_cb),
+		OPT_CALLBACK_F('z', NULL, &format, NULL,
+			       N_("synonym for --format=nul"),
+			       PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			       parse_format_cb),
 		OPT_END()
 	};
 
 	argc = parse_options(argc, argv, prefix, options, repo_usage, 0);
 
-	if (!strcmp(format_str, "keyvalue"))
-		format = FORMAT_KEYVALUE;
-	else if (!strcmp(format_str, "nul"))
-		format = FORMAT_NUL_TERMINATED;
-	else
-		die(_("invalid format '%s'"), format_str);
-
 	return print_fields(argc, argv, repo, format);
 }
 

t/t1900-repo.sh

@@ -92,4 +92,16 @@ test_expect_success 'git-repo-info aborts when requesting an invalid format' '
 	test_cmp expect actual
 '
 
+test_expect_success '-z uses nul-terminated format' '
+	printf "layout.bare\nfalse\0layout.shallow\nfalse\0" >expected &&
+	git repo info -z layout.bare layout.shallow >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'git repo info uses the last requested format' '
+	echo "layout.bare=false" >expected &&
+	git repo info --format=nul -z --format=keyvalue layout.bare >actual &&
+	test_cmp expected actual
+'
+
 test_done