Re: [PATCH/RFC] Add [] as an alias for a reference to the empty tree

On Fri, May 07, 2010 at 10:24:57PM -0700, Junio C Hamano wrote:

Jeff King [off-list ref] writes:

quoted

Based on past discussions, I suspect other people would be interested
in:

  $ git diff [index] HEAD
  $ git diff HEAD [index]
  $ git diff [working-tree] [index]

etc. I don't think I would want to type those all the time,...

If you go that route, why not use INDEX and WORKTREE (all caps) to at
least avoid the brackets?  I am not personally interested in [] at all,
but as part of that repertoire of syntactic sugar tokens EMPTY might be
able to sneak in [*1*]

Yeah, I would be fine with that (and I think I even suggested it the
last time this came up). In theory we can be breaking somebody's repo by
stealing from the valid ref namespace, but it really is not all that
likely (and I suppose we could prefer user refs).

*1* Without that "[]" syntax, the feature is "Meh" for me, but with the
syntax, it becomes "Yuck".  The reason I am not interested in the feature
is because I don't see much value in running "git diff EMPTY <anything>".
Perhaps "git archive" might be what the user really wants to find.

Somehow it comes up for me every once in a while, and I go look up the
empty tree sha1 in the source and use it, think "it would be nice if
there was a handy syntax", and then realize that it is the sort of thing
that only comes up infrequently, and even then only when you are trying
to do something a little odd, so it probably isn't worth caring about. I
wish I could remember the reason for the last time I needed it, but I
can't.

-Peff