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From: Siddharth Kannan <>
To: Junio C Hamano <>
Subject: Re: [PATCH/RFC] WIP: log: allow "-" as a short-hand for "previous branch"
Date: Tue, 7 Feb 2017 19:14:50 +0000	[thread overview]
Message-ID: <20170207191450.GA5569@ubuntu-512mb-blr1-01.localdomain> (raw)
In-Reply-To: <>

On Mon, Feb 06, 2017 at 03:09:47PM -0800, Junio C Hamano wrote:
> The focus of GSoC being mentoring those who are new to the open
> source development, and hopefully retain them in the community after
> GSoC is over, we do expect microprojects to be suitable for those
> who are new to the codebase.

Okay, understood! Since I have spent time here anyway, I guess I will
continue on this instead of going over to a new micro project.

> > (c) -> Else look for "r1^-"
> > ...
> > Case (c) is a bit confusing. This could be something like "-^-", and
> > something like "^-" could mean "Not commits on previous branch" or it
> > could mean "All commits on this branch except for the parent of HEAD"
> Do you mean:
>     "git rev-parse ^-" does not mean "git rev-parse HEAD^-", but we
>     probably would want to, and if that is what is going to happen,
>     "^-" should mean "HEAD^-", and cannot be used for "^@{-1}"?
> It's friend "^!" does not mean "HEAD^!", and "^@" does not mean
> "HEAD^@", either (the latter is somewhat borked, though, and "^@"
> translates to "^HEAD" because confusingly "@" stands for "HEAD"
> sometimes).  

Yes, I meant that whether we should use ^- as ^@{-1} or HEAD^-.

Oh! So, that's why running `git log ^@` leads to an empty set!
> So my gut feeling is that it is probably OK to make "^-" mean
> "^@{-1}"; it may be prudent to at least initially keep "^-" an error
> like it currently is already, though.

I agree with your gut feeling, and would like to _not_ exclude only
this case. This way, across the code and implementation, there
wouldn't be any particular cases which would have to be excluded.

> > So, this patch reduces to the following 2 tasks:
> > 
> > 1. Teach setup_revisions that something starting with "-" can be
> > an
> > argument as well
> > 2. Teach get_sha1_basic that "-" means the tip of the previous
> > branch
> > perhaps by replacing it with "@{-1}" just before the reflog
> > parsing is
> > done

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.

I hope that you do not mind this side-effect, but rather, you intended
for this to happen, right? More commands will start supporting this
shorthand, suddenly.  (such as format-patch, whatchanged, diff to name
a very few).

Best Regards,


  reply	other threads:[~2017-02-07 19:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-05 12:57 Siddharth Kannan
2017-02-05 14:55 ` Pranit Bauva
2017-02-06  0:15 ` Junio C Hamano
2017-02-06  2:27   ` Siddharth Kannan
2017-02-06 18:10   ` Siddharth Kannan
2017-02-06 23:09     ` Junio C Hamano
2017-02-07 19:14       ` Siddharth Kannan [this message]
2017-02-08 14:40         ` Matthieu Moy
2017-02-08 17:23           ` Siddharth Kannan
2017-02-09 12:25             ` Matthieu Moy
2017-02-09 18:21               ` Siddharth Kannan

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