Re: [PATCH 0/3] worktree: add --recurse-submodules support to git worktree add

[Junio C Hamano <gitster@pobox.com>]

Jimmy Aguilar Mena <kratsbinovish@gmail.com> writes:

> The approach follows Phillip Wood's and Junio's feedback: each linked
> worktree gets its own per-worktree submodule gitdir under
> $GIT_COMMON_DIR/worktrees/<id>/modules/<name>/, so HEAD, refs, and
> the index are independent per worktree while pack files and loose
> objects are shared via hardlinks.  The gitdir isolation is the same
> model git worktree already uses for the superproject.

I do not quite follow.  The point of git-native worktree support
(which improved a lot compared to its precursor, "git-new-workdir",
is that it can work well in a hardlink-challenged platforms.  You
shouldn't worry about "hardlinking" yourself at all.

After the superproject successfully did "submodule init", you can
move the submodule's repository with "absorbgitdirs" to
$GIT_DIR/modules/<submodule>/ of the superproject.  The primary
motivation behind this feature was that you can switch to a commit
in the superproject that does *not* have the submodule bound to it
at all (and obviously you do not want to lose the submodule
repository only because you tentatively switch to such a commit and
have to re-download when you switch back), but I think it gives the
single instance of submodule repository that you can share across
worktrees of the submodule.  Because the single directory created
with "absorbgitdirs" looks like a bare repository, you should be
able to create two worktrees off of that, with their own HEAD etc.