commit/status -h: show usage even with broken configuration

"git status" and "git commit" read .git/config and .gitmodules before
parsing options, but there is no reason to access a repository at all
when the caller just wanted to know what arguments are accepted.

[jn: rewrote the log message and added test]
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/commit.c

@@ -1070,6 +1070,9 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 		OPT_END(),
 	};
 
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(builtin_status_usage, builtin_status_options);
+
 	if (null_termination && status_format == STATUS_FORMAT_LONG)
 		status_format = STATUS_FORMAT_PORCELAIN;
 
@@ -1255,6 +1258,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	int allow_fast_forward = 1;
 	struct wt_status s;
 
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(builtin_commit_usage, builtin_commit_options);
+
 	wt_status_prepare(&s);
 	git_config(git_commit_config, &s);
 	in_merge = file_exists(git_path("MERGE_HEAD"));

t/t7508-status.sh

@@ -7,6 +7,30 @@ test_description='git status'
 
 . ./test-lib.sh
 
+test_expect_success 'status -h in broken repository' '
+	mkdir broken &&
+	test_when_finished "rm -fr broken" &&
+	(
+		cd broken &&
+		git init &&
+		echo "[status] showuntrackedfiles = CORRUPT" >>.git/config &&
+		test_expect_code 129 git status -h >usage 2>&1
+	) &&
+	grep "[Uu]sage" broken/usage
+'
+
+test_expect_success 'commit -h in broken repository' '
+	mkdir broken &&
+	test_when_finished "rm -fr broken" &&
+	(
+		cd broken &&
+		git init &&
+		echo "[status] showuntrackedfiles = CORRUPT" >>.git/config &&
+		test_expect_code 129 git commit -h >usage 2>&1
+	) &&
+	grep "[Uu]sage" broken/usage
+'
+
 test_expect_success 'setup' '
 	: >tracked &&
 	: >modified &&