Re: master^ is not a local branch -- huh?!?

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 30, 2010, 03:06 UTC
Message-ID: <7vvdek70ma.fsf@alter.siamese.dyndns.org>
In-Reply-To: <b4087cc51001291633l68760880i340d12e865641077@mail.gmail.com>

Michael Witten <mfwitten@gmail.com> writes:

> Isn't the difference between 'checkout' and 'reset' almost essentially
> a matter of whether the branch reference (HEAD), index, and tree are
> modified? Couldn't these commands be merged into one command or make
> use of one command?

I don't think that reduces any confusion.

By exposing orthogonal options like --index, --head, etc., you are opening yourself to nonsensical combinations that were never possible with the existing command set, and I suspect it would make it even more confusing, not less.

What does "git update --detach $commit" _really_ mean, for example?

You can of course say "it detaches the HEAD at $commit, but otherwise does not change anything else", but such a mechanical description does not give an answer that helps end users. "What would I do after doing that?" and "What would I use this for?" are the questions they need an answer to.

What matters is "after doing this, next commit will record _this_, which is often what users want in _that_ situation, and that is why this combination of options makes sense." Do all (or majority) of option combinations to your "update" think have _meaning_ in that sense? I don't think so.

Flexibility and orthogonality is often good, but uncontrolled flexibility is not. And I suspect your "git update" is just an uncontrolled mess that would not help users [*1*].

[Footnote]

*1* It is a different matter to have something like that as an ingredient to build Porcelain scripts out of. Porcelain writers may appreciate the flexibility and they will choose to use only combinations that make sense for the situation they are trying to deal with.