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

From: Duy Nguyen <pclouds@gmail.com>
Date: Jul 2, 2015, 12:50 UTC
Message-ID: <CACsJy8CYtey9d6dFhf+bKCPe0aKzm1GNURDR0sJ4NNEmdZeLGQ@mail.gmail.com>
In-Reply-To: <CACsJy8Dce4ErwaRM7zTgLmRzcHxKOr4J8St46urettr5R4DbVg@mail.gmail.com>

On Thu, Jul 2, 2015 at 7:41 PM, Duy Nguyen <pclouds@gmail.com> wrote:

Show 17 quoted lines

>> merge_working_tree:
>>     tree = parse_tree_indirect(old->commit &&
>>         !opts->new_worktree_mode ?
>>             old->commit->object.sha1 :
>>             EMPTY_TREE_SHA1_BIN);
>
> I think it's to make sure empty sha-1 is used with --to. If
> old->commit->object.sha1 is used and it's something, a real two way
> merge may happen probably with not-so-fun consequences. If it's empty
> sha1, the effect is like "reset --hard", silent and reliable..
>
>> switch_branches:
>>     if (!opts->quiet && !old.path && old.commit &&
>>         new->commit != old.commit && !opts->new_worktree_mode)
>>             orphaned_commit_warning(old.commit, new->commit);
>
> to suppress misleading warning if old.commit happens to be something.

Actually you may be right about not reverting these. We prepare the new worktree with a valid HEAD, that would make "old" valid and may trigger things if "git checkout" is used to populate the worktree. To suppress those "things", we need new_worktree_mode or something similar.

Unless we want to borrow fancy checkout options for "git worktree add", we probably should just export checkout() function from clone.c and use it instead of "git checkout". Much more lightweight and simpler (it's one-way merge). Then we can revert checkout.c to the version before "--to".

-- 
Duy