Re: [RFC/PATCH] worktree: replace "checkout --to" with "worktree new"

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Jul 2, 2015, 18:45 UTC
Message-ID: <CAPig+cR2tn6G0N1sSsrkP_Lo_U_hjLYi08qEsMr+gcsjheaX7A@mail.gmail.com>
In-Reply-To: <CAPig+cT=U6LxpJuUMaCd-x=gQPvh89SDNUo12+2_3uYb_q3=Og@mail.gmail.com>

On Wed, Jul 1, 2015 at 10:52 PM, Eric Sunshine <sunshine@sunshineco.com> wrote:

Show 20 quoted lines

> However, there are still a few bits of
> code which want to know that the checkout is happening in a new
> worktree. I haven't examined them closely yet to diagnose if this
> specialized knowledge can be eliminated. Perhaps you can weight in. In
> particular:
>
> checkout_paths:
>     if (opts->new_worktree)
>         die(_("'%s' cannot be used with updating paths"), "--to");
>
> merge_working_tree:
>     tree = parse_tree_indirect(old->commit &&
>         !opts->new_worktree_mode ?
>             old->commit->object.sha1 :
>             EMPTY_TREE_SHA1_BIN);
>
> switch_branches:
>     if (!opts->quiet && !old.path && old.commit &&
>         new->commit != old.commit && !opts->new_worktree_mode)
>             orphaned_commit_warning(old.commit, new->commit);

There's another instance: 3473ad0 (checkout: don't require a work tree when checking out into a new one, 2014-11-30) added this:

    if (!new_worktree)
        setup_work_tree();

which the "worktree add" patch changed to:

    setup_work_tree();

which doesn't hurt (since setup_work_tree() protects itself against multiple invocations) but isn't semantically clean. If I understand correctly, I think a better approach would be to move the setup_work_tree() call to worktree.c just before it invokes git-checkout, and revert 3473ad0 entirely (including this bit):

    - { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
    +{ "checkout", cmd_checkout, RUN_SETUP },

so that git-checkout once again requires a worktree.