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

[Mike Rappazzo <rappazzo@gmail.com>]

On Thu, Dec 13, 2018 at 3:43 PM Duy Nguyen <pclouds@gmail.com> wrote:
>
> On Thu, Dec 13, 2018 at 9:34 PM Mike Rappazzo <rappazzo@gmail.com> wrote:
> >
> > On Thu, Dec 13, 2018 at 3:23 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > >
> > > On Thu, Dec 13, 2018 at 8:56 PM Michael Rappazzo via GitGitGadget
> > > <gitgitgadget@gmail.com> wrote:
> > > >
> > > > From: Michael Rappazzo <rappazzo@gmail.com>
> > > >
> > > > On a worktree which is not the primary, using the symbolic-ref 'head' was
> > > > incorrectly pointing to the main worktree's HEAD.  The same was true for
> > > > any other case of the word 'Head'.
> > > >
> > > > Signed-off-by: Michael Rappazzo <rappazzo@gmail.com>
> > > > ---
> > > >  refs.c                   | 8 ++++----
> > > >  t/t1415-worktree-refs.sh | 9 +++++++++
> > > >  2 files changed, 13 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/refs.c b/refs.c
> > > > index f9936355cd..963e786458 100644
> > > > --- a/refs.c
> > > > +++ b/refs.c
> > > > @@ -579,7 +579,7 @@ int expand_ref(const char *str, int len, struct object_id *oid, char **ref)
> > > >                                 *ref = xstrdup(r);
> > > >                         if (!warn_ambiguous_refs)
> > > >                                 break;
> > > > -               } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
> > > > +               } else if ((flag & REF_ISSYMREF) && strcasecmp(fullref.buf, "HEAD")) {
> > >
> > > This is not going to work. How about ~40 other "strcmp.*HEAD"
> > > instances? All refs are case-sensitive and this probably will not
> > > change even when we introduce new ref backends.
> >
> > The current situation is definitely a problem.  If I am in a worktree,
> > using "head" should be the same as "HEAD".
>
> No "head" is not the same as "HEAD". It does not matter if you're in a
> worktree or not.

I was not aware of a difference.  Is that spelled out in the docs
somewhere?  It seems like a bad idea to have a magical symbolic ref
that _sometimes_ gives you a different answer depending on casing.
What should "head" do in a worktree?  Is it supposed to mean the HEAD
of the primary worktree?

>
> > I am not sure if you mean that the fix is too narrow or too wide.
> > Maybe it is only necessary in 'is_per_worktree_ref'.  On the other
> > side of the coin, I could change every strcmp to strcasecmp where the
> > comparison is against "HEAD".
>
> If you make "head" work like "HEAD", then it should work for _all_
> commands, not just worktree, and "MASTER" should match
> "refs/heads/master" and so on. I don't think it's as simple as
> changing strcmp to strcasecmp. You would need to make ref management
> case-insensitive (and make sure if still is case-sensitive if
> configured so). I don't think anybody has managed that.

I am all for making "head" work in all cases, not just worktree.  I
don't think that this situation applies to non-magical refs
(branches/tags).

> --
> Duy