From: Stefan Sperling <stsp@stsp.name>
Subject: Re: regress: change how trim_obj_id works
To: Omar Polo <op@omarpolo.com>
Cc: gameoftrees@openbsd.org
Date: Sat, 13 Jul 2024 16:43:25 +0200

On Sat, Jul 13, 2024 at 04:09:24PM +0200, Omar Polo wrote:
> Omar Polo <op@omarpolo.com> wrote:
> > trim_obj_ids is a bit weird IMHO in that you have to specify how many
> > characters to drop *from the end* instead of how many to keep from the
> > beginning.  This comes in the way of enabling some parts of the regress
> > for sha256 since object IDs are longer, and a `trim_obj_id 38` will not
> > yield 2 characters, but 26!
> > 
> > Instead, what about using the numeric argument to mean the number of
> > characters to keep from the beginning?  Then `trim_obj_id 2` will always
> > return the first two characters, regardless of the length of the hash.
> > 
> > The diff boils down to
> > 
> > @@ -132,13 +132,7 @@ trim_obj_id()
> >         local trimcount=$1
> >         local id=$2
> > 
> > -       local pat=""
> > -       while [ "$trimcount" -gt 0 ]; do
> > -               pat="[0-9a-f]$pat"
> > -               trimcount=$((trimcount - 1))
> > -       done
> > -
> > -       echo ${id%$pat}
> > +       echo "$id" | sed -E "s/^([0-9a-f]{$trimcount}).*/\1/"
> >  }
> > 
> > plus a mechanical fix for all the places where it's used.  Regress of
> > course passes.  ok?
> 
> forgot to stage a few files, here's a diff that fixes tog/ and gotd/
> too.
> 

yes ok, i already got confused about this myself on occasion.