Re: [PATCH v8 3/4] worktree add: add --orphan flag

[Jacob Abel <jacobabel@nullpo.dev>]

On 23/01/16 10:47AM, Phillip Wood wrote:
> Hi Jacob
>
> On 14/01/2023 22:47, Jacob Abel wrote:
> > On 23/01/13 10:20AM, Phillip Wood wrote:
> >> Hi Jacob
> >>
> > [...]
> >
> > I'll reply to this message with the one-off patch to get feedback. Since this is
> > essentially a discrete change on top of v8, I can either keep it as a separate
> > patch or reroll depending on how much needs to be changed (and what would be
> > easier for everyone).
> >
> >> 	git worktree add --orphan -b topic main
> >> 	git worktree add --orphan -B topic main
> >
> > I am hesitant to add these as they break away from the syntax used in
> > `git switch` and `git checkout`.
>
> When I wrote my original email I wrongly though that --orphan did not
> take an argument for "git checkout". While I think it is a mistake for
> checkout and switch to have --orphan take an argument they do at least
> always need a branch name with that option. "git worktree" add already
> has the branch name in the form of the worktree directory in the common
> case.

Understood.

I'm not entirely opposed to making this change to OPT_BOOL but I have to wonder
how often `--orphan` will actually be used by a given user and whether the
slightly shorter invocation will be used regularly.

With the base `git worktree add $path`, the shorthand/DWYM makes sense as it's
used regularly but I don't see users working with `--orphan` outside of trying
to create the first branch in a repository.

And I'd like that operation of creating the first branch in a repo to eventually
"just work" with the base command, i.e. `git worktree add main/`. The reason I
hadn't yet added that is because I've yet to figure out how to get it to work
without accidentally introducing potentially confusing situations and I didn't
want to hold up introducing the core functionality itself.

Once that main use-case "just works", I don't see users utilising `--orphan`
except in very rare circumstances. Doubly so since the average user likely
shouldn't be using `--orphan` in most cases.

Hence the question of whether this change would be worth it vs the existing
`--orphan $branchname $path` which is (for better or worse) consistent with `-b`
and `-B`.

>
> > Also apologies for the tangent but while researching this path, I noticed that
> > --orphan behaves unexpectedly on both `git switch` and `git checkout` when mixed
> > with `-c` and `-b` respectively.
> >
> >      % git switch --orphan -c foobar
> >      fatal: invalid reference: foobar
> >
> >      % git switch -c --orphan foobar
> >      fatal: invalid reference: foobar
> >      % git checkout -b --orphan foobar
> >      fatal: 'foobar' is not a commit and a branch '--orphan' cannot be created from it
> >
> >      % git checkout --orphan -b foobar
> >      fatal: 'foobar' is not a commit and a branch '-b' cannot be created from it
>
> The messages for checkout look better than the switch ones to me as they
> show the branch name which makes it clearer that we're treating what
> looks like an option as an argument. What in particular is unexpected
> here - --orphan and -b take an argument so they'll hoover up the next
> thing on the commandline whatever it is.
>
> Best Wishes
>
> Phillip
>
> > [...]

Agreed. I wasn't sure if this would be something worth addressing in a patch but
at the very least I can work on putting together a small patch for `git switch`
since it doesn't seem to be hoovering the flags like `git checkout` does.