Re: [BUG] credential wildcard does not match hostnames containing an underscore

> That may be so for hostnames in general, but URLs seem to allow it. RFC
> 3986 says:
> 
>       host        = IP-literal / IPv4address / reg-name
>       reg-name    = *( unreserved / pct-encoded / sub-delims )
>       unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"
> 
> So underscore is definitely allowed in the host portion. Our code
> complains during url_normalize(), in this code:
> 
>           if (allow_globs)
>                   spanned = strspn(url, URL_HOST_CHARS "*");
>           else
>                   spanned = strspn(url, URL_HOST_CHARS);
>   
>           if (spanned < colon_ptr - url) {
>                   /* Host name has invalid characters */
>                   if (out_info) {
>                           out_info->url = NULL;
>                           out_info->err = _("invalid characters in host name");
>                   }
>                   strbuf_release(&norm);
>                   return NULL;
>           }
> 
> because earlier we define URL_HOST_CHARS without underscore:
> 
>   #define URL_HOST_CHARS URL_ALPHADIGIT ".-[:]" /* IPv6 literals need [:] */
> 
> I'm not sure why, given that this otherwise seems to match according to
> the rfc. This code comes from 3402a8dc48 (config: add helper to
> normalize and match URLs, 2013-07-31), but there's no mention of
> underscore there. Possibly it came from earlier rules (rfc1738, for
> example, has a stricter grammar that allows only alphabit and dashes).