Re: [RFC] Using gitrevisions :/search style with other operators

[Yann Dirson <dirson@bertin.fr>]

On Tue, 09 Nov 2010 16:33:31 -0800
Kevin Ballard <kevin@sb.org> wrote:

> On Nov 9, 2010, at 4:18 PM, Junio C Hamano wrote:
> 
> > Yann Dirson <dirson@bertin.fr> writes:
> > 
> >>>> Syntax like origin/pu^{/Merge 'kb/blame-author-email'}2 would be
> >> ...
> >> Another idea: origin/pu^{:2/Merge 'kb/blame-author-email'}
> > 
> > What are these "2"s?
> > 
> > You need to question how you figured out the commit you want is the
> > second one reachable (in whatever traversal order) from something
> > in the first place.  Didn't you use "git log --oneline" or
> > something to find that out? At that point, you have the object name
> > already, so I doubt such a "counting" feature is of much practical
> > use.

I usually always have a gitk displaying history.  Whereas it shows the
commit summary, it does not show the sha1 for each commit - and even if
it did, my brain is still more comfortable dealing with words than
hashes (though that may arguably be an effect of aging ;)

> The particular case that prompted this for me was I knew I had
> created two commits called "WIP", scheduled for renaming later, and I
> wanted to quickly look at the contents of the first one. I would have
> loved to be able to type something like `git show :/WIP/2`. I suppose
> this situation may be rare enough not to bother supporting it in the
> new syntax. With the new syntax it will be possible to do something
> like `git show HEAD^{:/WIP}^^{:/WIP}`, but that looks awfully awkward.

Another use for counting would be for reflog, to lookup things like
"2nd to last of yesterday's commits" - that could be spelled like
"master^{:2:yesterday}" or similar.  Not sure it's worth it (I hardly
use the @{anything vague} syntax myself, especially because it is so
vague), but that looked similar enough to be mentionned here.

> Another thing to consider - the current :/foo syntax searches for the
> newest commit reachable from any ref. Using the ^{} syntax will
> require specifying a ref first. I'm not sure this is a problem
> though, as I'm not really sure why :/foo searches from all refs to
> begin with.

The syntax could be extended so that ^{whatever} starts looking at
current commit (ie. HEAD), somewhat like @{whatever} looks at reflog for
current branch.

-- 
Yann Dirson - Bertin Technologies