Re: New orphan worktree?

[Eric Sunshine <sunshine@sunshineco.com>]

On Wed, Feb 17, 2021 at 8:26 PM Ævar Arnfjörð Bjarmason
<avarab@gmail.com> wrote:
> On Wed, Jan 06 2021, Eric Sunshine wrote:
> > Yep, when/if --orphan is added to `git worktree add`, it should mimic
> > the behavior of --orphan in git-switch rather than git-checkout.
>
> How would a mode for "worktree add --orphan" that mimics checkout rather
> than switch even look like? The "checkout --orphan" special-case is
> because we retain the index, so you need to "git rm -rf .".
>
> But with worktrees we always get a new index, so AFAICT the only way to
> make it work like "checkout" would be to have it be the only mode that
> copies over the current worktree's index.

I hadn't actually put any thought into it aside from (1) `--orphan`
being a likely candidate for `git worktree add`, and (2) my uses of
orphan branches always involved `git checkout --orphan && git rm -rf
.`. I never got as far as thinking about the actual implementation.

> In any case I implemented a rough version of this today, and it uses the
> "switch" semantics. I only discovered this ML thread afterwards.
>
> It's surely full of bugs, and needs test work (see all the BUG(...)),
> but if someone's interested in taking it further all it should need is
> some more tests & dealing with the edge cases of incompatible options
> etc. It's Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>.

Thanks. This looks like a good start.

> +test_expect_success '"add" worktree orphan branch' '
> +       git worktree add --orphan -b orphan here-orphan &&

Rather than making --orphan a boolean flag, we'd probably want to
mirror the behavior of the other commands and have <branch> be an
argument consumed by --orphan:

    git worktree add --orphan <branch> <path>

That would make --orphan, -b, and -B mutually exclusive, much like
they are for git-checkout, and much like -c, -C, and --orphan are
mutually exclusive for git-switch.