Re: Commit-ish shortcut for immediate parent range

On Sun, Oct 22, 2006 at 03:48:35PM +0100, Andy Parkins wrote:

Git's commit-ish is very powerful.  I was wondering however, if there was a 
shortcut for (for example)?

 git-diff 3435fdb4c^..3435fdb4c

That is - the short range of a particular commit's parent to that commit; like

 git-diff 3435fdb4c!

Or similar.

I think a more general (but possibly harder to implement and use!) form
would be a commit-ish token for "refer to previous commit-ish." This
would not increase expressiveness, but could save a lot of typing. So if
'!' meant "the last sha1/ref parsed", your example range would be:

  3435fdb4c^..!

but you could also do more exotic things like:
  3435fdb4c~25..!~20

Obviously you could think of more interesting ways to refer to previous
THINGS. But I think in most cases in which you have repeated refs, you
really are just repeating one ref twice as a basis for a range.

The '!' character is probably a bad choice, since it's generally an
interactive shell metacharacter. I'm not sure what would be a better
choice; we're running low on punctuation.

At any rate, I'm not convinced this is a worthwhile optimization. It's
annoying to have to re-specify a long sha1, but in 99% of cases, you
really are looking for sha1^..sha1. As others have pointed out, that's
already handled through git-show.

-Peff