Re: [RFC/PATCH]: reverse bisect v 2.0

From: Jeff King <peff@peff.net>
Date: Oct 4, 2011, 10:30 UTC
Message-ID: <20111004103056.GB11236@sigill.intra.peff.net>
In-Reply-To: <7vfwjaggd2.fsf@alter.siamese.dyndns.org>

On Mon, Oct 03, 2011 at 10:00:25AM -0700, Junio C Hamano wrote:

Show 9 quoted lines

> > I like this idea a lot. My "yes/no" thing was a "if I were designing
> > bisect from scratch today..." suggestion, but having something like
> > --used-to makes it a natural addition to the regular good/bad interface.
> > And I really like the prompt to help people remember what it is they're
> > declaring each time.
> 
> I forgot to clarify that "tested" was only to help users who wanted
> reminder; if the user is confident with the usual "yes/no", the
> interactivity is not required.

That makes sense to me. I think in either case, it would be nice to mention the --used-to text when we take each step. We're already outputting some status information there (like how many commits left).

Show 9 quoted lines

> > However, --used-to feels a bit backwards to me. I think of it as
> > "--has-property" or something similar.
> 
> I do not think --used-to='frotz says xyzzy' is a good phrasing at all; it
> is grammatically incorrect. But --has-property has one large downside.  At
> least --used-to makes it clear that the user is supposed to decribe the
> property of the tree in the past.
> 
> Let's step back a bit to understand why I think this is not optimal.

What you say makes sense, but isn't it just a problem of the name? IOW, a much better name than "--has-property" would be "--started-to". That would imply the exact same cutoff as --used-to, but negate only the yes/no bit.

So you could say:

  # find a bug:
  git bisect start --used-to='work with --foo=bar'

  # or if you are looking for a specific undesirable behavior, you might
  # write:
  git bisect start --used-to='not segfault with --foo=bar'

  # but now you have a negation in your condition. So it might be more
  # natural to write it as:
  git bisect start --started-to='segfault with --foo=bar'

  # Or we can find a feature
  git bisect start --used-to='not respect core.foo'

  # but again, we have a negation. Instead:
  git bisect start --started-to='respect core.foo'

And the --started-to would literally be implemented as flipping the meaning of "git bisect yes" and "git bisect no", and nothing more. IOW, it's just another way of spelling "git bisect --reverse".

I know you wanted to emphasize the "older tree has this property" of --used-to, but I think it is clear with --started-to that the older tree obviously obviously had the negation of the property.

-Peff