Re: [PATCH v5 5/6] worktree: teach "add" to check out existing branches

> On Sun, Mar 25, 2018 at 9:49 AM, Thomas Gummerer <t.gummerer@gmail.com> wrote:
> > Currently 'git worktree add <path>' creates a new branch named after the
> > basename of the path by default.  If a branch with that name already
> > exists, the command refuses to do anything, unless the '--force' option
> > is given.
> >
> > However we can do a little better than that, and check the branch out if
> > it is not checked out anywhere else.  This will help users who just want
> > to check an existing branch out into a new worktree, and save a few
> > keystrokes.
> > [...]
> > Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
> > ---
> > diff --git a/builtin/worktree.c b/builtin/worktree.c
> > @@ -317,7 +318,10 @@ static int add_worktree(const char *path, const char *refname,
> > -       if (opts->new_branch)
> > +       if (opts->checkout_existing_branch)
> > +               fprintf_ln(stderr, _("checking out branch '%s'"),
> > +                          refname);
> 
> This fprintf_ln() can easily fit on one line; no need to wrap
> 'refname' to the next one.
> 
> Not worth a re-roll, though.
> 
> > +       else if (opts->new_branch)
> >                 fprintf_ln(stderr, _("creating branch '%s'"), opts->new_branch);
> > diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
> > @@ -198,13 +198,26 @@ test_expect_success '"add" with <branch> omitted' '
> > -test_expect_success '"add" auto-vivify does not clobber existing branch' '
> > +test_expect_success '"add" checks out existing branch of dwimd name' '
> >         test_commit c1 &&
> >         test_commit c2 &&
> >         git branch precious HEAD~1 &&
> > -       test_must_fail git worktree add precious &&
> > +       git worktree add precious &&
> >         test_cmp_rev HEAD~1 precious &&
> > -       test_path_is_missing precious
> > +       (
> > +               cd precious &&
> > +               test_cmp_rev precious HEAD
> > +       )
> > +'
> 
> Looking at this more closely, once it stops being a "don't clobber
> precious branch" test, it's doing more than it needs to do, thus is
> confusing for future readers. The setup -- creating two commits and
> making "precious" point one commit back -- was very intentional and
> allowed the test to verify not only that the worktree wasn't created
> but that "precious" didn't change to reference a different commit.
> However, _none_ of this matters once it becomes a dwim'ing test; the
> unnecessary code is confusing since it doesn't make sense in the
> context of dwim'ing. I _think_ the entire test can collapse to:
> 
>     git branch existing &&
>     git worktree add existing &&
>     (
>         cd existing &&
>         test_cmp_rev existing HEAD
>     )
> 
> In other words, this patch should drop the "precious" test altogether
> and just introduce a new dwim'ing test (and drop patch 6/6).
> 
> I do think that with the potential confusion to future readers, this
> does deserve a re-roll.

> > +test_expect_success '"add" auto-vivify fails with checked out branch' '
> > +       git checkout -b test-branch &&
> > +       test_must_fail git worktree add test-branch &&
> > +       test_path_is_missing test-branch
> > +'
> > +
> > +test_expect_success '"add --force" with existing dwimd name doesnt die' '
> > +       git worktree add --force test-branch
> >  '