merge: ensure '--abort' option takes no arguments

Like '--continue', the '--abort' option doesn't make any sense with
other options or arguments to 'git merge' so ensure that none are
present.
Signed-off-by: NChris Packham <judge.packham@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/merge.c

@@ -1163,6 +1163,10 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		int nargc = 2;
 		const char *nargv[] = {"reset", "--merge", NULL};
 
+		if (orig_argc != 2)
+			usage_msg_opt("--abort expects no arguments",
+			      builtin_merge_usage, builtin_merge_options);
+
 		if (!file_exists(git_path_merge_head()))
 			die(_("There is no merge to abort (MERGE_HEAD missing)."));
 

t/t7600-merge.sh

@@ -154,6 +154,8 @@ test_expect_success 'test option parsing' '
 	test_must_fail git merge -s foobar c1 &&
 	test_must_fail git merge -s=foobar c1 &&
 	test_must_fail git merge -m &&
+	test_must_fail git merge --abort foobar &&
+	test_must_fail git merge --abort --quiet &&
 	test_must_fail git merge --continue foobar &&
 	test_must_fail git merge --continue --quiet &&
 	test_must_fail git merge