notes: check number of parameters to "git notes copy"

Otherwise we may segfault with too few parameters.
Signed-off-by: NJeff King <peff@peff.net>
Tested-by: NBert Wesarg <Bert.Wesarg@googlemail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/notes.c

@@ -614,6 +614,10 @@ static int copy(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (argc < 2) {
+		error("too few parameters");
+		usage_with_options(git_notes_copy_usage, options);
+	}
 	if (2 < argc) {
 		error("too many parameters");
 		usage_with_options(git_notes_copy_usage, options);

t/t3301-notes.sh

@@ -1044,4 +1044,10 @@ test_expect_success 'GIT_NOTES_REWRITE_REF overrides config' '
 	git log -1 > output &&
 	test_cmp expect output
 '
+
+test_expect_success 'git notes copy diagnoses too many or too few parameters' '
+	test_must_fail git notes copy &&
+	test_must_fail git notes copy one two three
+'
+
 test_done