Re: [PATCH v2] parse-opt: migrate builtin-checkout-index.

Miklos Vajna [off-list ref] writes:

+static int option_parse_z(const struct option *opt,
+			  const char *arg, int unset)
+{
+	line_termination = unset;
+	return 0;
+}
...
+		{ OPTION_CALLBACK, 'z', NULL, NULL, NULL,
+			"paths are separated with NUL character",
+			PARSE_OPT_NOARG, option_parse_z },

This adds a new feature to say --no-z from the command line, doesn't it?
And I suspect the feature is broken ;-).

+		OPT_BOOLEAN(0, "stdin", &read_from_stdin,
+			"read list of paths from the standard input"),
...
+	argc = parse_options(argc, argv, builtin_checkout_index_options,
+			builtin_checkout_index_usage, 0);
+	state.force = force;
+	state.quiet = quiet;
+	state.not_new = not_new;
+	if (argc && read_from_stdin)
+		die("--stdin must be at the end");

Is this comment still correct?  Do the original and your version act the
same way when the user says "checkout --stdin -f", for example?  I suspect
the original refused it and yours take it (and do much more sensible
thing), which would be an improvement, but then the error message should
be reworded perhaps?