Re: [PATCH/RFC] git.c: support "!!" aliases that do not move cwd

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

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Hi Duy,

On Fri, 7 Oct 2016, Duy Nguyen wrote:

> On Fri, Oct 7, 2016 at 6:20 PM, Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
> >
> > On Thu, 6 Oct 2016, Junio C Hamano wrote:
> >
> >> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> >>
> >> > Throwing something at the mailing list to see if anybody is
> >> > interested.
> >> >
> >> > Current '!' aliases move cwd to $GIT_WORK_TREE first, which could make
> >> > handling path arguments hard because they are relative to the original
> >> > cwd. We set GIT_PREFIX to work around it, but I still think it's more
> >> > natural to keep cwd where it is.
> >> >
> >> > We have a way to do that now after 441981b (git: simplify environment
> >> > save/restore logic - 2016-01-26). It's just a matter of choosing the
> >> > right syntax. I'm going with '!!'. I'm not very happy with it. But I
> >> > do like this type of alias.
> >>
> >> I do not know why you are not happy with the syntax, but I
> >> personally think it brilliant, both the idea and the preliminary
> >> clean-up that made this possible with a simple patch like this.
> >
> > I guess he is not happy with it because "!!" is quite unintuitive a
> > construct. I know that *I* would have been puzzled by it, asking "What the
> > heck does this do?".
> 
> Yep. And I wouldn't want to set a tradition for the next alias type
> '!!!'. There's no good choice to represent a new alias type with a
> leading symbol. This just occurred to me, however, what do you think
> about a new config group for it? With can have something like
> externalAlias.* (or some other name) that lives in parallel with
> alias.*. Then we don't need '!' (or '!!') at all.

But what would the precedence be? externalAlias.xyz wins over alias.xyz?

And we still would need '!' support: tons of people (including myself)
rely on it.

Possibly a better idea would be to use *another* special symbol, one that
makes intuitive sense as a modifier, such as:

	[alias]
		# This works as before
		xyz = !pwd
		# As does this
		stat = -p status
		# This, however, is different:
		duy = (nocd)!pwd

This is backwards compatible as "(" is not a part of any Git command, nor
of a valid alias, nor is it commonly used as part of a git-*
executable/script.

It is also kind of a bit more intuitive, I'd wager, and it is also
extensible to future options we may want to introduce.

Ciao,
Dscho