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

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.

Nguyễn Thái Ngọc Duy (4):
  revision.c: move read_cache() out of add_index_objects_to_pending()
  reachable.c: mark reachable objects in index from all worktrees
  reachable.c: mark reachable detached HEAD from all worktrees
  reachable.c: make reachable reflogs for all per-worktree reflogs

 reachable.c      | 47 +++++++++++++++++++++++++++++++++++++++++------
 revision.c       | 34 +++++++++++++++++++++++++++-------
 revision.h       |  7 ++++++-
 t/t5304-prune.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 114 insertions(+), 14 deletions(-)