shortlog: disallow left-over arguments outside repo

If we are outside a repo and have any arguments left after
option-parsing, `setup_revisions()` will try to do its job and
something like this will happen:

$ git shortlog v2.16.0..
BUG: environment.c:183: git environment hasn't been setup
Aborted (core dumped)

The usage is wrong, but we could obviously handle this better. Note that
commit abe549e179 (shortlog: do not require to run from inside a git
repository, 2008-03-14) explicitly enabled `git shortlog` to run from
outside a repo, since we do not need a repo for parsing data from stdin.

Disallow left-over arguments when run from outside a repo.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/shortlog.c

@@ -293,6 +293,11 @@ int cmd_shortlog(int argc, const char **argv, const char *prefix)
 parse_done:
 	argc = parse_options_end(&ctx);
 
+	if (nongit && argc > 1) {
+		error(_("too many arguments given outside repository"));
+		usage_with_options(shortlog_usage, options);
+	}
+
 	if (setup_revisions(argc, argv, &rev, NULL) != 1) {
 		error(_("unrecognized argument: %s"), argv[1]);
 		usage_with_options(shortlog_usage, options);

t/t4201-shortlog.sh

@@ -127,6 +127,11 @@ test_expect_success !MINGW 'shortlog can read --format=raw output' '
 	test_cmp expect out
 '
 
+test_expect_success 'shortlog from non-git directory refuses extra arguments' '
+	test_must_fail env GIT_DIR=non-existing git shortlog foo 2>out &&
+	test_i18ngrep "too many arguments" out
+'
+
 test_expect_success 'shortlog should add newline when input line matches wraplen' '
 	cat >expect <<\EOF &&
 A U Thor (2):