From: Michael Haggerty <mhagger@alum.mit.edu>
Date: Tue, 02 Apr 2013 16:32:58 GMT
Subject: Re: [PATCH 2/2] peel_onion(): teach $foo^{object} peeler
Message-ID: <515B083A.5050808@alum.mit.edu>
In-Reply-To: <7vfvz9gclo.fsf@alter.siamese.dyndns.org>

On 04/02/2013 05:45 PM, Junio C Hamano wrote:
> Michael Haggerty <mhagger@alum.mit.edu> writes:
> 
>> Off topic: Your patch reminds me of something else that surprised me:
>> there is no "$userstring^{tag}".  I suppose it would be a bit ambiguous,
>> given that tags can point at tags, and it would also be less useful than
>> the other suffixes.  But its absence irked the completionist in me :-)
> 
> Yes, unfortunately, foo^{type} means "start from foo, and until what
> you are looking at it is of type, repeatedly peel to see if you can
> get to an object of that type, or stop and report an error".  If a
> tag A points at another tag B, which in turn points at an object C,
> you will never see B by applying usual peeling operator.
> 
> Also, v1.8.2^{tag} would be give the tag itself, while master^{tag}
> would not report the commit "master" but would error out, which
> would be useless.  You are better off doing `git cat-file -t foo`
> and seeing if it is a tag object at that point.

All correct, of course.  But the user would never use "master^{tag}"
unless he wants a tag and nothing else, so erroring out would be exactly
the thing he wants in that case.  This is no different than the
"^{commit}" part of "master^{tree}^{commit}", which correctly errors out
because a commit cannot be inferred from a tree.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/