Re: [PATCH 0/4] Fix prune/gc problem with multiple worktrees

[Jeff King <peff@peff.net>]

On Wed, Jun 01, 2016 at 05:45:15PM +0700, Nguyễn Thái Ngọc Duy wrote:

> This series makes sure that objects referenced by all worktrees are
> marked reachable so that we don't accidentally delete objects that are
> being used. Previously per-worktree references in index, detached HEAD
> or per-worktree reflogs come from current worktree only, not all
> worktrees.
> 
> The series deals with git-prune and git-gc specifically. I left out
> "git rev-list". It shares the same problem because it will only
> consider current worktree's HEAD, index and per-worktree reflogs. The
> problem is I am not sure if we simply just change, say
> --indexed-objects, to cover all indexes, or should we only do that
> with "--all-worktrees --indexed-objects". I guess this is up for
> discussion.

I don't think touching reachable.c is enough. You also need to make sure
that calling "git pack-objects --indexed-objects" will get them, too
(otherwise they will be either ejected loose or dropped completely
when --unpack-unreachable=2.weeks.ago or similar is used).

That code path uses rev-list internally. So I think you need something
like "--all-worktrees --indexed-objects", and you need to pass the new
option in from git-repack to pack-objects (or you need to simply make
"--indexed-objects" cover all worktrees by default).

-Peff