Re: [PATCH 1/1] worktree refs: fix case sensitivity for 'head'

[Duy Nguyen <pclouds@gmail.com>]

On Fri, Dec 14, 2018 at 6:38 PM Duy Nguyen <pclouds@gmail.com> wrote:
>
> On Fri, Dec 14, 2018 at 6:22 PM Jacob Keller <jacob.keller@gmail.com> wrote:
> >
> > On Thu, Dec 13, 2018 at 11:38 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > > Even with a new ref storage, I'm pretty sure pseudo refs like HEAD,
> > > FETCH_HEAD... will forever be backed by filesystem. HEAD for example
> > > is part of the repository signature and must exist as a file. We could
> > > also lookup pseudo refs with readdir() instead of lstat(). On
> > > case-preserving-and-insensitive filesystems, we can reject "head" this
> > > way. But that comes with a high cost.
> > > --
> > > Duy
> >
> > Once other refs are backed by something that doesn't depend on
> > filesystem case sensitivity, you could enforce that we only accept
> > call-caps HEAD as a psuedo ref, and always look up other spellings in
> > the other refs backend, though, right?
>
> Hmm.. yes. I don't know off hand if we have any pseudo refs in
> lowercase. Unlikely so yes this should work.

One thing we could do _today_ without waiting for a new refs backend
is, avoid looking up pseudo refs if the given ref name is not
all-caps. So "head" (or hEAd) can match refs/head, refs/tags/head,
refs/heads/head but never $GIT_DIR/HEAD. And yes I checked the code,
pseudo refs must be all-caps.
-- 
Duy