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

> Even though parse-options doesn't support UTF-8 switches (which
> makes sense; non-ascii switches would be difficult to enter on
> some keyboard layouts), it can be useful to report incorrectly
> entered UTF-8 switches to make the output somewhat less ugly
> for those of us with keyboard layouts with UTF-8 characters on
> it.
> 
> Make the reporting code grok UTF-8 in the option sequence, and
> write a variable-width output sequence.
> 
> Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
> ---
> As being both clumsy and Norwegian, I some times to enter the
> Norwegian bizarro-letters ('æ', 'ø' and 'å') instead of the
> correct ones when entering command-line options.
> 
> 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.
> 
> The "real fix" would probably be to add proper multi-byte
> support to the short-option parser, but this serves little
> purpose in Git; we don't internationalize the command-line
> switches.
> 
> So perhaps this is a suitable band-aid instead?
> 
>  parse-options.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/parse-options.c b/parse-options.c
> index 67e98a6..20dc742 100644
> --- a/parse-options.c
> +++ b/parse-options.c
> @@ -3,6 +3,7 @@
>  #include "cache.h"
>  #include "commit.h"
>  #include "color.h"
> +#include "utf8.h"
>  
>  static int parse_options_usage(struct parse_opt_ctx_t *ctx,
>  			       const char * const *usagestr,
> @@ -462,7 +463,9 @@ int parse_options(int argc, const char **argv, const char *prefix,
>  		if (ctx.argv[0][1] == '-') {
>  			error("unknown option `%s'", ctx.argv[0] + 2);
>  		} else {
> -			error("unknown switch `%c'", *ctx.opt);
> +			const char *next = ctx.opt;
> +			utf8_width(&next, NULL);
> +			error("unknown switch `%.*s'", (int)(next - ctx.opt), ctx.opt);
>  		}
>  		usage_with_options(usagestr, options);
>  	}
>