Re: some apparent inaccuracies in "man git-worktree"

> On Tue, Nov 14, 2017 at 3:43 AM, Robert P. J. Day <rpjday@crashcourse.ca> wrote:
> > from "man git-worktree", there seem to be some inaccuracies in the
> > SYNOPSIS regarding the "add" subcommand:
> >
> >   git worktree add \
> >     [-f] [--detach] [--checkout] [--lock] [-b <new-branch>] <path> [<branch>]
> >
> >   first, there's no mention of "-B" in that SYNOPSIS, even though it's
> > explained further down the man page.
>
> Omission of "-B" from the synopsis was intentional. From cbdf60fa18
> (worktree: add -b/-B options, 2015-07-06):
>
>     worktree: add -b/-B options
>
>     One of git-worktree's roles is to populate the new worktree, much like
>     git-checkout, and thus, for convenience, ought to support several of the
>     same shortcuts. Toward this goal, add -b/-B options to create a new
>     branch and check it out in the new worktree.
>
>     (For brevity, only -b is mentioned in the synopsis; -B is omitted.)
>
> Whether or not the omission was actually a good decision is
> questionable. The thinking, at the time, may have been that users
> already familiar with "-b" in 'git checkout' would likewise be
> familiar with (and be able to infer) "-B", thus it wasn't important to
> state its existence explicitly in the synopsis, which was already
> getting lengthy. Of course, that decision does not assist newcomers,
> so adding "-B" to the synopsis would help the page better stand on its
> own.
>
> >   next, the SYNOPSIS seems misleading as it doesn't make clear that
> > the options -b, -B and --detach are mutually exclusive, which is made
> > clear in the worktree.c source:
> >
> >     if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
> >             die(_("-b, -B, and --detach are mutually exclusive"));
>
> Failure to update the synopsis to indicate mutual exclusion appears to
> be a simple oversight in ab0b2c53ed (worktree: make --detach mutually
> exclusive with -b/-B, 2015-07-17) in response to:
> https://public-inbox.org/git/55A8F4B1.9060304@drmicha.warpmail.net/
>
> >   finally (and maybe i'm just not reading carefully enough), it's not
> > clear what happens if you add a worktree at a given commit without
> > specifying *any* of -b, -B or --detach. the obvious result should be a
> > new worktree checked out at a detached HEAD and, interestingly, if i
> > do that, then from the main tree, i see:
> >
> >   $ git worktree list
> >   /home/rpjday/k/git   516fb7f2e73d [master]
> >   /home/rpjday/k/temp  c470abd4fde4 (detached HEAD)
> >   $
> >
> > but from within the worktree, if i ask for the status, i see only:
> >
> >   $ git status
> >   Not currently on any branch.
> >   nothing to commit, working tree clean
> >   $
> >
> > where i would normally have expected to see "detached HEAD", is there
> > a reason that's not displayed?
>
> Someone more familiar with this bit can correct me if I'm wrong, but I
> believe that the "HEAD detached at/from <branch>" you normally see
> with 'git status' is derived from the reflog, and if it can't find the
> information in the reflog, it instead shows the generic "Not currently
> on any branch" (which is the equivalent of the "(detached HEAD)" you
> see in "git worktree list").
>
> Each worktree has its own newly-created reflog, which does _not_
> contain enough information for 'git status' to present the more
> detailed "detached" message, thus it falls back to the generic one.
> Perhaps seeding the worktree's reflog with a bit more information at
> creation time would be a good #leftoverbits task.