Re: [PATCH] branch: add '-' to delete previous branch

[Taylor Blau <me@ttaylorr.com>]

Hi Ivan,

On Thu, Apr 30, 2020 at 10:52:21PM +0800, Ivan Tham wrote:
> On Wed, Apr 29, 2020 at 12:58:51PM -0600, Taylor Blau wrote:
> > On Wed, Apr 29, 2020 at 09:01:33PM +0800, Ivan Tham wrote:
> > > Add support to delete previous branch from git checkout/switch to have
> > > feature parity with git switch -.
> > >
> > > Signed-off-by: Ivan Tham <pickfire@riseup.net>
> > > ---
> > >  Documentation/git-branch.txt | 10 ++++++++++
> > >  builtin/branch.c             |  6 +++++-
> > >  t/t3200-branch.sh            |  7 +++++++
> > >  3 files changed, 22 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
> > > index 135206ff4a..37e7cbbc52 100644
> > > --- a/Documentation/git-branch.txt
> > > +++ b/Documentation/git-branch.txt
> > > @@ -265,6 +265,10 @@ start-point is either a local or remote-tracking branch.
> > >  	The new branch name must pass all checks defined by
> > >  	linkgit:git-check-ref-format[1].  Some of these checks
> > >  	may restrict the characters allowed in a branch name.
> > > ++
> > > +You can use the `@{-N}` syntax to refer to the N-th last branch checked out
> > > +using "git checkout" operation. You may also specify `-` which is synonymous to
> > > +`@{-1}`.
> >
> > Interesting; we're already using strbuf_branchname, so the first part of
> > this documentation was true even before this commit. Would you consider
> > splitting this into two patches?
> >
> > The first should include the first sentence of this documentation, an
> > additional test in t3200 exercising an explicit 'git branch -D @{-N}'
> > for some 'N', but no changes in builtin/branch.c. The second patch would
> > then make '-' a synonym for '@{-1}'.
>
> Is not this already true? Why do we need to split it? Currently using
> '@{-N}' to delete branch already works.

It is the case that 'git branch -D @{-N}' already works, which was
surprising to me. I am suggesting that you make documenting the existent
behavior a new first patch.

Of course, that might be the only patch that you end up sending in v2,
since it seems that consensus has formed around not supposing '-' as a
shorthand for '@{-1}' with 'git branch -D'.

Thanks,
Taylor