Re: [BUG] branch renamed to 'HEAD'

[Jeff King <peff@peff.net>]

On Mon, Feb 27, 2017 at 11:43:46AM +0530, Karthik Nayak wrote:

> On Mon, Feb 27, 2017 at 10:22 AM, Luc Van Oostenryck
> <luc.vanoostenryck@gmail.com> wrote:
> > Hi,
> >
> > I just discover something which very much seems a bug to me
> > while making an error in renaming a branch.
> > The scenario is the following:
> > - I have a branch named 'orig'
> > - I want to make some experimental changes on it:
> >         $ git checkout -b temp orig
> >         $ ... edit some files ...
> >         $ ... make some tests & commits ...
> > - I'm happy with my changes, so I want to have my original
> >   branch to now points to the head of this temp branch
> >   but did it wrongly:
> >         $ git branch -m -f orig @
> 
> Here you are using the '-m' flag, which is to rename a branch. So what
> you're essentially
> doing is:
>     $ git branch -m -f orig HEAD
> Do note that this won't reset 'orig' to point to 'HEAD', rather this
> renames 'orig' to 'HEAD'.
> 
> What you actually want to do (to reset 'orig' to 'HEAD') is:
>     $ git branch -f orig @
> This would make orig point to the current HEAD.

Regardless of the original intent, I think it is wrong to convert "@" to
a branch named "HEAD". I think the bug is in strbuf_check_branch_ref(),
which blindly sticks "refs/heads/" in front of any value we get from
interpret_branch_name(), which clearly does not make sense for HEAD.

-Peff