Re: [PATH/RFC] parse-options: report invalid UTF-8 switches

From: Jeff King <peff@peff.net>
Date: Feb 11, 2013, 17:19 UTC
Message-ID: <20130211171957.GG16402@sigill.intra.peff.net>
In-Reply-To: <7v7gmeok2e.fsf@alter.siamese.dyndns.org>

On Mon, Feb 11, 2013 at 09:07:53AM -0800, Junio C Hamano wrote:

Show 8 quoted lines

> Erik Faye-Lund <kusmabite@gmail.com> writes:
> 
> > However, since git only looks at one byte at the time for
> > short-options, it ends up reporting a partial UTF-8 sequence
> > in such cases, leading to corruption of the output.
> 
> Isn't it a workable, easier and more robust alternative to punt and
> use the entire ctx.argv[0] as unrecognized?

Yes, but it regresses the usability:

  [before]
  $ git foobar -qrxs
  unknown switch: x

  [after]
  $ git foobar -qrxs
  unknown switch: -qrxs

One is much more informative than the other, and you are punishing the common ascii case for the extremely uncommon case of utf-8. Maybe:

  if (isascii(*ctx.opt))
          error("unknown option `%c'", *ctx.opt);
  else
          error("unknown multi-byte short option in string: `%s'", ctx.argv[0]);

which only kicks in in the uncommon case (and extends the error message to make it more clear why we are showing the whole string).

-Peff