Re: Updated Kernel Hacker's guide to git

["Francis Moreau" <francis.moro@gmail.com>]

On 12/22/06, Junio C Hamano <junkio@cox.net> wrote:
> "Francis Moreau" <francis.moro@gmail.com> writes:
>
> > I think this part is really confusing. For a new comer, saying that:
> >
> >       git diff a b == git diff a..b
> >
> > is really not intuitive. Maybe just because adding a new symbol ".."
> > in git diff command line means (for me) that we're doing a special
> > diff. I would never thought by my own that ".." means a simple "to".
>
> We did not originally have "A B"; you were supposed to always
> say "A..B".  But all other SCM had "A B" notation, so we added
> support for both because doing so was trivial and there is no
> risk of confusion (because diff is about two points while log is
> about a set).  These two notations are interchangeable for
> "diff".  If it confuses you, you can stick to the "git diff A B"
> notation.  Of if you are like Linus, stick to "A..B" notation.
> Either way, you can pretend that the other notation does not
> even exist and be happy ;-).
>

no, no, I think you miss my point here. What is confusing, and it
seems I'm not the only one to find it confusing,  is the fact that
"git diff A B == git diff A..B", not the "A..B" notation per se.

git diff A B, is really intuitive and easy to understand because we
all use to using the diff "A B" notation and it always has worked with
2 endpoints. So I would bet that all newbies who use for the first
time the git diff command will use "A B" notation, not "A..B" one.

> Yes, users often wondered why "git diff" accepts "A B", "git
> log" wants "A..B" and "git log A B" is a disaster.  But the root
> cause of the confusion was not about notation but about the
> conceptual difference (two points vs a set).
>
> I do not think changing the meaning of "diff A..B" to what "diff
> A...B" means is a good thing.  The notation "..." even _looks_
> like a magic, and in diff context, what it does _is_ magic (it
> is magic in log context, too).  You are giving two points, but

But ".." is magic too ! I would really expect something magic to
happen when using the "A..B" notation because I'm a new comer in git
and I never used the "A..B" notation before.

And since I already used this notation when using git log command, I
would expect "git diff A..B" to give the current result given by "git
diff A...B".

But yes, now I have understand that git diff works with end points
unlike git log, I can stick with two notations:

        git diff A B
        git diff A...B (3 dots)

and I'm happy ;)

thanks
-- 
Francis