repo: add -z as an alias for --format=nul to git-repo-structure

Other Git commands that have nul-terminated output, such as git-config,
git-status, git-ls-files, and git-repo-info have a flag `-z` for using
the null character as the record separator.

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

Signed-off-by: Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-repo.adoc

@@ -9,7 +9,7 @@ SYNOPSIS
 --------
 [synopsis]
 git repo info [--format=(keyvalue|nul) | -z] [--all | <key>...]
-git repo structure [--format=(table|keyvalue|nul)]
+git repo structure [--format=(table|keyvalue|nul) | -z]
 
 DESCRIPTION
 -----------
@@ -44,7 +44,7 @@ supported:
 +
 `-z` is an alias for `--format=nul`.
 
-`structure [--format=(table|keyvalue|nul)]`::
+`structure [--format=(table|keyvalue|nul) | -z]`::
 	Retrieve statistics about the current repository structure. The
 	following kinds of information are reported:
 +
@@ -71,6 +71,8 @@ supported:
 	the delimiter between the key and value instead of '='. Unlike the
 	`keyvalue` format, values containing "unusual" characters are never
 	quoted.
++
+`-z` is an alias for `--format=nul`.
 
 INFO KEYS
 ---------

builtin/repo.c

@@ -16,7 +16,7 @@
 
 static const char *const repo_usage[] = {
 	"git repo info [--format=(keyvalue|nul) | -z] [--all | <key>...]",
-	"git repo structure [--format=(table|keyvalue|nul)]",
+	"git repo structure [--format=(table|keyvalue|nul) | -z]",
 	NULL
 };
 
@@ -529,6 +529,10 @@ static int cmd_repo_structure(int argc, const char **argv, const char *prefix,
 		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_BOOL(0, "progress", &show_progress, N_("show progress")),
 		OPT_END()
 	};

t/t1901-repo-structure.sh

@@ -101,6 +101,13 @@ test_expect_success 'keyvalue and nul format' '
 		tr "\n=" "\0\n" <expect >expect_nul &&
 		git repo structure --format=nul >out 2>err &&
 
+		test_cmp expect_nul out &&
+		test_line_count = 0 err &&
+
+		# "-z", as a synonym to "--format=nul", participates in the
+		# usual "last one wins" rule.
+		git repo structure --format=table -z >out 2>err &&
+
 		test_cmp expect_nul out &&
 		test_line_count = 0 err
 	)