Detached HEADs in new worktrees considered harmful

Before someone loses their HEAD I should put this series out (again).

1/6 is a tiny documentation fix.

2/6 demonstrates that "git prune" in the main worktree loses HEADs in other worktrees, and vice versa.

In fact, one should rethink the meaning of "git rev-list --all" in the context of per-worktree refs such as HEAD.

3/6 is a possible fix (making "--all" mean "all refs in all worktrees") but may be too intrusive.

4/6, 5/6, 6/6 are some WIP patches about making 3/6 less intrusive and fixing some cases where do_head_ref_worktrees() has problems that do_head_ref() doesn't have.

Michael J Gruber (6):
Documentation/git-worktree: spell --detach correctly
t6014: test prune with detached HEADs in separate worktrees
rev-list: list all heads with --all
WIP: mess only with mark_reachable
fix unborn branch case
revisions: list all worktree HEADs with --all

 Documentation/git-worktree.txt     |  2 +-
 Documentation/rev-list-options.txt |  2 +-
 reachable.c                        |  2 +-
 refs.h                             |  1 +
 refs/files-backend.c               | 34 +++++++++++++++++++++++++++++++++-
 t/t6014-rev-list-all.sh            | 25 +++++++++++++++++++++++++
 6 files changed, 62 insertions(+), 4 deletions(-)

2.7.2.618.g7a61b68