Re: [PATCH 2/3] credential: teach `credential_from_url()` a non-strict mode

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Junio,

On Thu, 23 Apr 2020, Junio C Hamano wrote:

> Junio C Hamano <gitster@pobox.com> writes:
>
> > Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> >
> >> Yes (modulo doing "greater than" comparison on pointers which is IIRC not
> >> permitted in C in general).
> >
> > Of course, people write a loop like this
> >
> > 	char *cp, *ep = strchr(string, '\n');
> >
> > 	for (cp = string; cp < ep; cp++)
> > 		...
> >
> > all the time, and forbidding pointer comparison would make the
> > language impossible to use ;-)
> >
> > I think you are confused with a different rule---what is not kosher
> > is to compare two pointers that do not point into elements of the
> > same array.  Whether the comparison is done in (ptr1 < ptr2) way, or
> > (ptr2 - ptr1 < 0) way, does not change the equation.

Yep, that's my confusion all right.

> Having said that, between
>
> 1.	if (strict || slash - url > 0)
> 2.	if (strict || slash > url)
>  		c->host = url_decode_mem(host, slash - host);
>
> I think the former is moderately easier to read.  It still has the
> same "Huh?" factor that a comparison between slash and URL guards
> the size of the region being decoded, which is slash - host, and
> makes the reader wonder how these two variables, URL and host,
> relate to each other at this point in the code, though, either way
> the comparison is spelled.

I fully agree! That's why I use `strict || slash - host > 0` in my next
iteration (actually, I decided to rename `strict`, but that's beside the
point).

Ciao,
Dscho