[PATCH v2 GSoC RFC] diff: allow "-" as a short-hand for "last branch"

Hey, I have already worked on this, and I made the change inside
sha1_name.c.

The final version of my patch is here[1].

Handling the dash in sha1_name:get_sha1_basic is not an issue but
git
was designed with the dash in mind for options not for this weird
short-hand so as long as there's no decision made that git should
actually have this short-hand everywhere it does not seem like a
good
idea to change anything in there because it would probably have
unwanted side-effects.

Actually, this was discussed even when I was working on this patch.

I said [2]

Making a change in sha1_name.c will touch a lot of commands
(setup_revisions is called from everywhere in the codebase), so, I
am
still trying to figure out how to do this such that the rest of the
codepath remains unchanged.

Matthieu replied to this [3]

I don't have strong opinion on this: I tend to favor consistency and
supporting "-" everywhere goes in this direction, but I think the
downsides should be considered too. A large part of the exercice
here
is to write a good commit message!

From the discussion over the different versions of my patch, I get
the feeling that enabling this shorthand for all the commands is the
direction that git wants to move in.

Sorry about the time you spent on this patch.

[1]: http://public-inbox.org/git/1488007487-12965-1-git-send-email-kannan.siddharth12@gmail.com/
[2]: https://public-inbox.org/git/20170207191450.GA5569@ubuntu-512mb-blr1-01.localdomain/
[3]: https://public-inbox.org/git/vpqh944eof7.fsf@anie.imag.fr/

Thanks,
Siddharth.

P.S. This message was sent _before_ 1cmCXH-0000ND-9K@crossperf.com but
I didn't CC The mailing list in that message. I am sending it with the
mailing list cc-ed to ensure that the conversation makes sense.